SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Björkman Burtscher Isabella) "

Sökning: WFRF:(Björkman Burtscher Isabella)

  • Resultat 1-50 av 98
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Horsch, S., et al. (författare)
  • Randomized Control Trial of Postnatal rhIGF-1/rhIGFBP-3 Replacement in Preterm Infants: Post-hoc Analysis of Its Effect on Brain Injury
  • 2020
  • Ingår i: Frontiers in Pediatrics. - : Frontiers Media SA. - 2296-2360. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Postnatal insulin-like growth factor-1 (IGF-1) replacement with recombinant human (rh)IGF-1 and IGF binding protein-3 (rhIGF-1/rhIGFBP-3) is being studied as a potential treatment to reduce comorbidities of prematurity. We have recently reported on a phase II, multicenter, randomized, controlled trial comparing postnatal rhIGF-1/rhIGFBP-3 replacement with standard of care (SOC) in extremely preterm infants (NCT01096784). Maximum severity of retinopathy of prematurity was the primary endpoint of the trial and presence of GMH-IVH/PHI one of the pre-specified secondary endpoints. Infants therefore received serial cranial ultrasound scans (CUS) between birth and term age. In this post-hoc analysis we present a detailed analysis of the CUS data of this trial and evaluate the effect of postnatal rhIGF-1/rhIGFBP-3 replacement on the incidence of different kinds of brain injury in extremely preterm infants. Methods: This report is an exploratory post-hoc analysis of a phase II trial in which infants <28 weeks gestational age were randomly allocated to rhIGF-1/rhIGFBP-3 or SOC. Serial cranial ultrasounds were performed between birth and term-equivalent age. Presence of germinal matrix hemorrhage and intraventricular hemorrhage (GMH-IVH), periventricular hemorrhagic infarction (PHI), post-hemorrhagic ventricular dilatation, and white matter injury (WMI) were scored by two independent masked readers. Results: The analysis included 117 infants; 58 received rhIGF-1/rhIGFBP-3 and 59 received SOC. A trend toward less grade II-III GMH-IVH and PHI was observed in treated infants vs. SOC. A subanalysis of infants without evidence of GMH-IVH at study entry (n = 104) showed reduced progression to GMH-IVH in treated infants (25.0% [13/52] vs. 40.4% [21/52]; not significant). No effects of rhIGF-1/rhIGFBP-3 on WMI were observed. Conclusion: The potential protective effect of rhIGF-1/rhIGFBP-3 on the occurrence of GMH-IVH/PHI appeared most pronounced in infants with no evidence of GMH-IVH at treatment start.
  •  
2.
  • Björkman, Anders, et al. (författare)
  • Factor V leiden and prothrombin gene mutation: risk factors for osteonecrosis of the femoral head in adults.
  • 2004
  • Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X. ; :425, s. 168-172
  • Tidskriftsartikel (refereegranskat)abstract
    • The purpose of the current study was to determine whether factor V Leiden and the prothrombin 20210A gene mutation are risk factors for osteonecrosis of the femoral head in different etiologic groups of osteonecrosis in adults and whether patients with idiopathic osteonecrosis of the femoral head have a higher frequency of thromboembolic events compared with the general population. We investigated 63 adult patients with nontraumatic osteonecrosis of the femoral head for etiologic factors, such as corticosteroid medication and alcohol abuse, and the occurrence of factor V Leiden and the prothrombin 20210A gene mutation. In 35 patients, the disease was considered idiopathic and 10 of these patients (29%) had factor V Leiden or the prothrombin 20210A gene mutation or both. Mutations in factor V or the prothrombin 20210A gene were significantly more frequent in patients with idiopathic osteonecrosis than in a population of healthy control subjects (odds ratio, 2.7; 95% confidence interval range, 1.2-5.8) and in patients with osteonecrosis caused by corticosteroid medication or alcohol abuse (odds ratio, 10.8; 95% confidence interval range, 1.4-84). 36% of patients with a gene mutation had had a thromboembolic event compared with 8% of patients without a gene mutation. Thromboembolic events were more common among patients with idiopathic osteonecrosis (17%) compared with the general population (4%) and with patients with osteonecrosis caused by corticosteroid medication or alcohol abuse (7%).
  •  
3.
  •  
4.
  •  
5.
  • Björkman, Anders, et al. (författare)
  • Phantom digit somatotopy: a functional magnetic resonance imaging study in forearm amputees.
  • 2012
  • Ingår i: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 36:1, s. 2098-2106
  • Tidskriftsartikel (refereegranskat)abstract
    • Forearm amputees often experience non-painful sensations in their phantom when the amputation stump is touched. Cutaneous stimulation of specific stump areas may be perceived as stimulation of specific phantom fingers (stump hand map). The neuronal basis of referred phantom limb sensations is unknown. We used functional magnetic resonance imaging to demonstrate a somatotopic map of the phantom fingers in the hand region of the primary somatosensory cortex after tactile stump stimulation. The location and extent of phantom finger activation in the primary somatosensory cortex corresponded well to the location of normal fingers in a reference population. Stimulation of the stump hand map resulted in an increased bilateral activation of the primary somatosensory cortex compared with stimulation of forearm regions outside the stump hand map. Increased activation was also seen in contralateral posterior parietal cortex and premotor cortex. Ipsilateral primary somatosensory cortex activation might represent a compensatory mechanism and activation of the non-primary fronto-parietal areas might correspond to awareness of the phantom limb, which is enhanced when experiencing the referred sensations. It is concluded that phantom sensation elicited by stimulation of stump hand map areas is associated with activation of finger-specific somatotopical representations in the primary somatosensory cortex. This suggests that the primary somatosensory cortex could be a neural substrate of non-painful phantom sensations. The stump hand map phenomenon might be useful in the development of prosthetic hand devices.
  •  
6.
  • Björkman, Anders, et al. (författare)
  • Sensory qualities of the phantom hand map in the residual forearm of amputees
  • 2016
  • Ingår i: Journal of Rehabilitation Medicine. - : Medical Journals Sweden AB. - 1651-2081 .- 1650-1977. ; 48:4, s. 70-365
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: Most amputees experience referred sensations, known as a phantom hand map, on the residual forearm, where touch on specific areas is perceived as touch on the amputated hand. The aim of this study was to evaluate the sensory qualities of the phantom hand map.METHODS: In 10 traumatic forearm-amputees touch thres-holds and discriminative touch of the phantom hand map were assessed and compared with corresponding areas on the contralateral forearm. The study assessed the localization of touch on the phantom hand map, and how distinct and similar to normal touch the referred feeling was.RESULTS: Similar touch thresholds were seen in the phantom hand map and the control site. Tactile discrimination, requiring both detection of stimulus and interpretation, was significantly better in the phantom hand map.CONCLUSION: This explorative study suggests that the phantom hand map and the superior tactile discrimination seen in the phantom hand map are based on adaptations within the brain. Further studies investigating the neural basis for the phantom hand map are needed.
  •  
7.
  • Götestrand, Simon, et al. (författare)
  • Visualization of wrist anatomy - a comparison between 7T and 3T MRI
  • 2022
  • Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 32:2, s. 1362-1370
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective Injuries to the wrist are, due to its small size and complex anatomical structures, difficult to assess by MR, and surgical interventions such as diagnostic arthroscopy are often necessary. Therefore, improved visualization using non-invasive methods could be of clinical value. As a first step of improvement, the purpose of this study was to evaluate visualization of anatomical structures at 7T compared with 3T MR. Methods Eighteen healthy volunteers (three males and three females from each age decade between 20 and 49 years) were examined with 7T and 3T MR. Four musculoskeletal radiologists graded 2D and 3D images on a five-level grading scale for visibility of ligaments, cartilage, nerves, trabecular bone, and tendons, as well as overall image quality (i.e., edge sharpness, perceived tissue contrast, and presence of artefacts). Statistical analysis was done using a visual grading characteristics (VGC) analysis. Results Visibility of cartilage, trabecular bone, tendons, nerves, and ligaments was graded significantly higher at 7T with an area under the curve (AUC(VGC)) of 0.62-0.88 (95% confidence interval [CI] 0.50-0.97, p = < 0.0001-0.03) using either 2D or 3D imaging. Imaging with 3T was not graded as superior to 7T for any structure. Image quality was also significantly superior at 7T, except for artefacts, where no significant differences were found. Conclusions Tendons, trabecular bone, nerves, and ligaments were all significantly better visualized at 7T compared to 3T.
  •  
8.
  • Götestrand, Simon, et al. (författare)
  • Visualization of wrist ligaments with 3D and 2D magnetic resonance imaging at 3 Tesla
  • 2022
  • Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 63:3, s. 368-375
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Wrist ligaments are challenging to visualize using magnetic resonance imaging (MRI). Injuries involving the scapholunate ligament (SLL), the lunotriquetral ligament (LTL), and the triangular fibrocartilage complex (TFCC) are common and difficult to diagnose, often requiring diagnostic arthroscopy. Purpose To compare the visualization of wrist ligaments on a three-dimensional (3D) sequence with two-dimensional (2D) sequences on 3-T MRI. Material and Methods Eighteen healthy volunteers were examined with a 3D SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) sequence and 2D coronal, axial, and sagittal proton density-weighted (PD) sequences. Four musculoskeletal radiologists graded the anatomical visibility of the SLL, LTL, TFCC, and the image quality, using five grades in a visual grading characteristics (VGC) evaluation. After Bonferroni correction, a P value <= 0.005 was considered statistically significant. Results The 3D images were graded significantly better than the 2D images in the visualization of the dorsal and palmar parts of the SLL and the LTL. Regarding the TFCC, the 3D images were graded significantly better for visualization of the foveal attachment. 2D imaging was not found significantly superior to 3D imaging in any aspect. Conclusion The 3D SPACE sequence was scored as superior to the 2D sequences at 3 T in the assessment of the SLL, the LTL, and the foveal attachment of the TFCC. Thus, 3D SPACE can replace 2D PD sequences when these ligaments need to be assessed.
  •  
9.
  • Jörgsholm, Peter, et al. (författare)
  • Extension block pinning of mallet fractures.
  • 2010
  • Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Medical Journals Sweden AB. - 1651-2073. ; 44:1, s. 54-58
  • Tidskriftsartikel (refereegranskat)abstract
    • The operative treatment of mallet fractures of more than one third of the articular surface is controversial. The purpose of this study was to evaluate the complications and functional outcome of extension block pinning technique. Thirty-six consecutive patients with mallet fractures that involved more than one third of the joint surface were treated by extension block pinning a median of 3 days after injury (range 0-35, mean 7). Clinical outcome was graded according to Crawford's criteria. At a median follow-up of 16.5 months (range 2.5-52, mean 20) 23 patients had an excellent or good result, 11 patients had a fair, and 2 patients a poor, clinical outcome according to Crawford's criteria. None of the patients complained of pain. The median extension loss was 0 degrees (range 0-20, mean 4) and the median flexion was 70 degrees (range 30-95, mean 68). Eight patients had operative or direct postoperative complications including superficial infection (n = 6), loss of Kirschner wire (K-wire) fixation (n = 1), and K-wire mal position (n = 1). The extension block pinning technique is a minimally invasive method of treating mallet fractures with low morbidity and a good functional outcome.
  •  
10.
  • Maripuu, Amanda, et al. (författare)
  • Reconstruction of sciatic nerve after traumatic injury in humans - factors influencing outcome as related to neurobiological knowledge from animal research
  • 2012
  • Ingår i: Journal of Brachial Plexus and Peripheral Nerve Injury. - : Georg Thieme Verlag KG. - 1749-7221. ; 7:1, s. 40-52
  • Forskningsöversikt (refereegranskat)abstract
    • Background: The aim was to evaluate what can be learned from rat models when treating patients suffering from a sciatic nerve injury.Methods: Two patients with traumatic sciatic nerve injury are presented with examination of motor and sensory function with a five-year follow-up. Reconstruction of the nerve injury was performed on the second and third day, respectively, after injury using sural nerve grafts taken from the injured leg. The patients were examined during follow-up by electromyography (EMG), MRI and functionalMRI (fMRI) to evaluate nerve reinnervation, cell death in dorsal root ganglia (DRG) and cortical activation; factors that were related to clinical history in the patients.Results: One patient regained good motor function of the lower leg and foot, confirmed by EMG showing good activation in the leg muscles and some reinnervation in the foot muscles, as well as some sensory function of the sole of the foot. The other patient regained no motor (confirmed by EMG) or sensory function in the leg or foot. Factors most influential on outcome in two cases were type of injury, nerve gap length and particularly type of reconstruction. A difference in follow-up and rehabilitation likely also influence outcome. MRI did not show any differences in DRG size of injured side compared to the uninjured side. fMRI showed normal activation in the primary somatosensory cortex as a response to cutaneous stimulation of the normal foot. However, none of the two patients showed any activation in the primary somatosensory cortex following cutaneous stimulation of the injured foot.Conclusions: In decision making of nerve repair and reconstruction data from animal experiments can be translated to clinical practice and to predict outcome in patients, although such data should be interpreted with caution and linked to clinical experience. Rat models may be useful to identify and study factors that influence outcome after peripheral nerve repair and reconstruction; procedures that should be done correctly and with a competent team. However, some factors, such as cognitive capacity and coping, known to influence outcome following nerve repair, are difficult to study in animal models. Future research has to find and develop new paths and techniques to study changes in the central nervous system after nerve injury and develop strategies to utilize brain plasticity during the rehabilitation.
  •  
11.
  • Agerskov, Simon, et al. (författare)
  • MRI diffusion and perfusion alterations in the mesencephalon and pons as markers of disease and symptom reversibility in idiopathic normal pressure hydrocephalus
  • 2020
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction Core symptomatology in idiopathic normal pressure hydrocephalus (iNPH) points at dysfunction in the mesencephalon and pons indicating pathological changes in these regions, but only a few studies have addressed the issue. The aim of this study was to investigate diffusion (ADC) and perfusion patterns pre- and postoperatively in these areas in iNPH. Methods Twenty iNPH patients and 15 healthy controls were included. Patients underwent a clinical examination and brain MRI pre- and 3-6 months postoperatively. The MRI-scan included diffusion and dynamic susceptibility contrast perfusion weighted sequences. Regions of interest in the mesencephalon and pons were drawn on a FLAIR sequence and co-registered to ADC maps and perfusion data. Results There were no significant differences in pre or postoperative ADC compared to the control group, however postoperative ADC increased by 10% (p = 0.026) in the mesencephalon and 6% (p = 0.016) in the pons in all patients and also in the subgroup of shunt responders by 11% (p = 0.021) and 4% (p = 0.020), respectively. Preoperative relative cerebral blood flow (rCBF) was similar in iNPH patients and controls. Postoperatively, rCBF increased in shunt responders by 6% (p = 0.02) in the mesencephalon and 11% (p = 0.004) in the pons. This increase correlated with the degree of clinical improvement (r(s)= 0.80, p = 0.031 and r(s)= 0.66, p = 0.021, respectively). Conclusion The postoperative increase in ADC and the correlation between postoperative increase in rCBF and clinical improvement in the mesencephalon and pons shown in this study point at an involvement of these areas in the core pathophysiology and its reversibility in iNPH.
  •  
12.
  • Andersen, Mads, et al. (författare)
  • Improvement in diagnostic quality of structural and angiographic MRI of the brain using motion correction with interleaved, volumetric navigators
  • 2019
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction Subject movements lead to severe artifacts in magnetic resonance (MR) brain imaging. In this study we evaluate the diagnostic image quality in T1-weighted, T2-weighted, and timeof-flight angiographic MR sequences when using a flexible, navigator-based prospective motion correction system (iMOCO). Methods Five healthy volunteers were scanned during different movement scenarios with and without (+/-) iMOCO activated. An experienced neuroradiologist graded images for image quality criteria (grey-white-matter discrimination, basal ganglia, and small structure and vessel delineation), and general image quality on a four-grade scale. Results In scans with deliberate motion, there was a significant improvement in the image quality with iMOCO compared to the scans without iMOCO in both general image impression (T1 p<0.01, T2 p<0.01, TOF p = 0.03) and in anatomical grading (T1 p<0.01, T2 p<0.01, TOF p = 0.01). Subjective image quality was considered non-diagnostic in 91% of the scans with motion -iMOCO, but only in 4% of the scans with motion +iMOCO. iMOCO performed best in the T1-weighted sequence and least well in the angiography sequence. iMOCO was not shown to have any negative effect on diagnostic image quality, as no significant difference in diagnostic quality was seen between scans -iMOCO and +iMOCO with no deliberate movement. Conclusion The evaluation showed that iMOCO enables substantial improvements in image quality in scans affected by subject movement, recovering important diagnostic information in an otherwise unusable scan.
  •  
13.
  • Andersson, Linnea, et al. (författare)
  • Independent component analysis of rsfMRI data in pedophilic disorder: A Swedish case control study
  • 2022
  • Ingår i: Annual Meeting ISMRM (International Society of Magnetic Resonance in Medicine).
  • Konferensbidrag (refereegranskat)abstract
    • Fifty percent of all child sexual abuse (CSA) perpetrators are individuals with pedophilic disorder. The neural underpinnings of pedophilic disorder are unknown. We conducted a case-control study aiming to investigate functional connectivity alterations using independent component analysis on resting state fMRI data in search of biomarkers that can be used for preventing CSA. The results suggest there are functional connectivity alterations in several resting state networks in individuals with pedophilic disorder.
  •  
14.
  • Bergquist, Magnus, 1960-, et al. (författare)
  • Trust and stakeholder perspectives on the implementation of AI tools in clinical radiology
  • 2024
  • Ingår i: European Radiology. - Heidelberg : Springer. - 0938-7994 .- 1432-1084. ; 34:1, s. 338-347
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: To define requirements that condition trust in artificial intelligence (AI) as clinical decision support in radiology from the perspective of various stakeholders and to explore ways to fulfil these requirements.Methods: Semi-structured interviews were conducted with twenty-five respondents—nineteen directly involved in the development, implementation, or use of AI applications in radiology and six working with AI in other areas of healthcare. We designed the questions to explore three themes: development and use of AI, professional decision-making, and management and organizational procedures connected to AI. The transcribed interviews were analysed in an iterative coding process from open coding to theoretically informed thematic coding.Results: We identified four aspects of trust that relate to reliability, transparency, quality verification, and inter-organizational compatibility. These aspects fall under the categories of substantial and procedural requirements.Conclusions: Development of appropriate levels of trust in AI in healthcare is complex and encompasses multiple dimensions of requirements. Various stakeholders will have to be involved in developing AI solutions for healthcare and radiology to fulfil these requirements. Clinical relevance statement: For AI to achieve advances in radiology, it must be given the opportunity to support, rather than replace, human expertise. Support requires trust. Identification of aspects and conditions for trust allows developing AI implementation strategies that facilitate advancing the field.Key Points:• Dimensions of procedural and substantial demands that need to be fulfilled to foster appropriate levels of trust in AI in healthcare are conditioned on aspects related to reliability, transparency, quality verification, and inter-organizational compatibility.  • Creating the conditions for trust to emerge requires the involvement of various stakeholders, who will have to compensate the problem’s inherent complexity by finding and promoting well-defined solutions. © 2023, The Author(s).
  •  
15.
  • Björkman-Burtscher, Isabella, et al. (författare)
  • Aneurysm clip MR artifacts. Titanium versus stainless steel and influence of imaging parameters
  • 1998
  • Ingår i: Acta Radiologica. - 1600-0455. ; 39:1, s. 70-76
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: The aim of this study was to evaluate the extent to which titanium aneurysm clips could improve the quality of MR imaging compared with stainless steel clips, and to determine whether the clip artifacts could be reduced by controlling certain MR imaging parameters in frequently used pulse sequences. MATERIAL AND METHODS: The metal artifacts induced by 3 aneurysm clips were compared in 3 pulse sequences. The clips were: a Yasargil titanium aneurysm clip FT 752 T; a Yasargil standard aneurysm clip FE 752 K; and, for comparison, a ferromagnetic Scoville aneurysm clip En-58J. The pulse sequences were: spin echo (SE); gradient echo (GE); and fast SE. An evaluation was made of 3 imaging parameters with regard to their influence on the size of the metal artifacts. The parameters were: bandwidth; echo time (TE); and echo-train length. RESULTS: The titanium clip showed artifacts that were about 60% smaller than those from the stainless steel clip. The only parameter that influenced artifact size to any major degree was bandwidth in the SE sequences but not in the GE sequences. GE sequences induced larger artifacts than SE sequences and showed larger artifacts with longer TE. CONCLUSION: Titanium aneurysm clips reduced MR artifacts by approximately 60% compared to stainless steel clips. Artifacts were further reduced by using SE-based sequences with a high bandwidth or, if necessary, GE sequences with a low TE.
  •  
16.
  • Björkman-Burtscher, Isabella, et al. (författare)
  • In vivo proton MR spectroscopy of untreated and treated brain abscesses
  • 1999
  • Ingår i: AJNR. - 1936-959X. ; 20:6, s. 1049-1053
  • Tidskriftsartikel (refereegranskat)abstract
    • MR spectroscopy was performed in three patients with brain abscesses. In two patients, MR spectroscopy revealed end-products of bacterial breakdown (acetate, succinate, amino acids, lactate) in the abscess cysts. In one of these, the spectrum was reversed to a single lactate peak after treatment. In the third patient, MR spectroscopy was performed only after treatment and showed a single nonspecific lactate peak. MR spectroscopy is a potential tool for noninvasive diagnosis of brain abscess and might be useful for evaluating changes after treatment.
  •  
17.
  • Björkman-Burtscher, Isabella M., et al. (författare)
  • Detailed anatomy at 7T
  • 2017
  • Ingår i: Neuroimaging : Anatomy Meets Function - Anatomy Meets Function. - Cham : Springer International Publishing. - 9783319574264 - 9783319574271 ; , s. 69-80
  • Bokkapitel (refereegranskat)
  •  
18.
  • Björkman-Burtscher, Isabella M., et al. (författare)
  • Detailed anatomy at 7T
  • 2017
  • Ingår i: Neuroimaging : Anatomy Meets Function - Anatomy Meets Function. - Cham : Springer International Publishing. - 9783319574264 - 9783319574271 ; , s. 145-151
  • Bokkapitel (refereegranskat)abstract
    • Selected high resolution axial images obtained from a 7T MRI scanner have been labeled to provide detailed information about the subtle structures found in the cerebellum and brainstem.
  •  
19.
  •  
20.
  • Björkman-Burtscher, Isabella, et al. (författare)
  • Proton (1H) MR spectroscopy for routine diagnostic evaluation of brain lesions
  • 1997
  • Ingår i: Acta Radiologica. - 1600-0455. ; 38:6, s. 953-960
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To describe the introduction and performance of proton MR spectroscopy (1H-MRS) in the daily routine of a modern standard MR unit. MATERIAL AND METHODS: Over an 8-month period, 52 patients with brain lesions were studied with 1H-MRS, using SE and STEAM sequences for chemical-shift imaging and single-volume spectroscopy. The quality of the spectra was graded from 1 (best) to 3, and the main factors influencing the quality of the spectra were evaluated. RESULTS: Of the measurements: 85% were graded as 1; 12% as 2; and 3% as 3. The main reasons for poor spectral quality were: the unfortunate positioning of the VOI; hemorrhage; and/or postoperative changes within the VOI. Of 40 patients with a final diagnosis: MRS provided an increased confidence in MR diagnosis in 18 cases; MRS contributed significantly to preoperative diagnosis in 3 cases; and the spectra were not specific (n = 10) or were difficult to evaluate (n = 9) owing to reduced quality (grade 2 or 3) in 19 cases. CONCLUSION: MRS of the brain can provide a high percentage of interpretable spectra and frequently can increase confidence in the MR diagnosis of brain lesions in clinical routine.
  •  
21.
  • Björkman-Burtscher, Isabella (författare)
  • Proton Magnetic Resonance Spectroscopy in Brain Tumors - Clinical Applications
  • 1999
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Aims: · to present a test phantom and test method for evaluation of proton magnetic resonance spectroscopy (1H-MRS) single volume localization techniques regarding signal contamination; · to describe the introduction of 1H-MRS in the daily routine of a standard MR-unit; · to evaluate the possibilities offered by 1H-MRS to improve preoperative diagnostic accuracy in patients scheduled for stereotactic biopsy of intracranial mass lesions; · to evaluate the possibilities offered by 1H-MRS to improve diagnostics and therapy control in patients with brain abscesses; · to test the hypothesis that 1H-MRS might be useful for differentiation of brain tumors, based on metabolic changes in tissue across brain lesions or surrounding tissue. Results and conclusions: · The test phantom and test method allow quality assessment with good reproducibility. Contamination values for the tested sequence types and sizes of volume of interest (VOI) differed between 0.7% and 13.8% in one dimension and between 7% and 19.1% in three dimensions. · Of the first 102 MRS measurements performed 85% were of high spectral quality. Main reasons for poor quality were mal-positioning of the VOI, susceptibility problems due to hemorrhage, and post operative changes. · Metabolite ratios of normal tissue differed from those representing stereotactic target points. No significant difference between metabolite ratios representing different histopathologic tumor types could be seen. MRS could improve diagnostic accuracy in differentiation between infiltrating and circumscribed brain lesions based on different spatial distribution of pathologic spectra across the lesion. · MR spectra from abscesses showed resonances, not found in other intracranial pathologies and vanishing under antibiotic treatment, and can therefore be used to differentiate abscesses from other ring-enhancing lesions and might be used for therapy control. · Metabolite ratios representing different components of brain lesions or adjacent tissue differed significantly for the following differential diagnoses: a) high-grade glioma versus metastasis: NAA/Cho and Cr/Cho in contrast-enhancing tissue, and NAA/Cho in tissue adjacent to and at one voxel distance to the lesion; b) meningeoma versus low-grade glioma and metastasis: NAA/Cho in contrast-enhancing tissue; c) low-grade glioma versus metastasis: NAA/Cr in tissue adjacent to the lesion. Our data support the hypothesis that proton MRS can be useful for the reliable differentiation between brain tumors, tending to infiltrate adjacent tissue, and circumscribed, non-infiltrating brain lesions.
  •  
22.
  • Björkman-Burtscher, Isabella, et al. (författare)
  • Proton MR spectroscopy and preoperative diagnostic accuracy: an evaluation of intracranial mass lesions characterized by stereotactic biopsy findings
  • 2000
  • Ingår i: AJNR. - 1936-959X. ; 21:1, s. 84-93
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND AND PURPOSE: MR imaging has made it easier to distinguish among the different types of intracranial mass lesions. Nevertheless, it is sometimes impossible to base a diagnosis solely on clinical and neuroradiologic findings, and, in these cases, biopsy must be performed. The purpose of this study was to evaluate the hypothesis that proton MR spectroscopy is able to improve preoperative diagnostic accuracy in cases of intracranial tumors and may therefore obviate stereotactic biopsy. METHODS: Twenty-six patients with intracranial tumors underwent MR imaging, proton MR spectroscopy, and stereotactic biopsy. MR spectroscopic findings were evaluated for the distribution pattern of pathologic spectra (NAA/Cho ratio < 1) across the lesion and neighboring tissue, for signal ratios in different tumor types, and for their potential to improve preoperative diagnostic accuracy. RESULTS: Gliomas and lymphomas showed pathologic spectra outside the area of contrast enhancement while four nonastrocytic circumscribed tumors (meningioma, pineocytoma, metastasis, and germinoma) showed no pathologic spectra outside the region of enhancement. No significant correlation was found between different tumor types and signal ratios. MR spectroscopy improved diagnostic accuracy by differentiating infiltrative from circumscribed tumors; however, diagnostic accuracy was not improved in terms of differentiating the types of infiltrative or circumscribed lesions. CONCLUSION: MR spectroscopy can improve diagnostic accuracy by differentiating circumscribed brain lesions from histologically infiltrating processes, which may be difficult or impossible solely on the basis of clinical or neuroradiologic findings.
  •  
23.
  • Björkman-Burtscher, Isabella, et al. (författare)
  • Quality assessment of localization technique performance in small volume in vivo 1H MR spectroscopy
  • 1999
  • Ingår i: Magnetic Resonance Imaging. - 1873-5894. ; 17:10, s. 1511-1519
  • Tidskriftsartikel (refereegranskat)abstract
    • A new phantom and evaluation method for experimental evaluation of 1H-magnetic resonance spectroscopy single volume localization techniques regarding signal contamination (C), defined as the part of the signal originating outside the volume of interest, is presented. The quality assessment method is based on a spherical phantom with an oil/water interface in order to reduce susceptibility effects, and applied for stimulated-echo acquisition method (STEAM) and spin-echo (SE) sequences, echo times of 270, 135, and 10 ms, and cubic volumes of interest (VOI) of 1(3), 1.5(3), 2(3), 2.5(3), and 3(3) cm3. To be able to mimic measurements of the contamination in three dimensions the physical gradients representing the three orthogonal directions for slice selection were shifted in the pulse sequences. Contamination values in one dimension differed between 6.5% and 8.4% in SE sequences, and between 0.7% and 13.8% in STEAM sequences. In STEAM sequences a decrease of C with increasing VOI size was observed while SE sequences showed comparable C values for the different VOI sizes tested. The total contamination in three dimensions were 19% and 18% in SE and STEAM sequences with a TE of 270 ms, and 7% in a STEAM sequence with a TE of 10 ms, respectively. The presented evaluation method is easily applied to the new phantom and showed high reproducibility.
  •  
24.
  • Bozovic, Gracijela, et al. (författare)
  • Circulation stabilizing therapy and pulmonary high-resolution computed tomography in a porcine brain-dead model.
  • 2016
  • Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172. ; 60:1, s. 93-102
  • Tidskriftsartikel (refereegranskat)abstract
    • Currently 80% of donor lungs are not accepted for transplantation, often due to fluid overload. Our aim was to investigate if forced fluid infusion may be replaced by a new pharmacological therapy to stabilize circulation after brain death in an animal model, and to assess therapy effects on lung function and morphology trough blood gas parameters and state-of-the-art High-resolution CT (HRCT).
  •  
25.
  • Bozovic, Gracijela, et al. (författare)
  • Imaging of the Lungs in Organ Donors and its Clinical Relevance : A Retrospective Analysis
  • 2017
  • Ingår i: Journal of thoracic imaging. - Philadelphia, USA : Lippincott Williams & Wilkins. - 0883-5993 .- 1536-0237. ; 32:2, s. 107-114
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: The aim of the study was to retrospectively evaluate the diagnostic imaging that potential lung donors undergo, the reader variability of image interpretation and its relevance for donation, and the potential information gained from imaging studies not primarily intended for lung evaluation but partially including them.Materials and methods: Bedside chest radiography and computed tomography (CT), completely or incompletely including the lungs, of 110 brain-dead potential organ donors in a single institution during 2007 to 2014 were reviewed from a donation perspective. Two chest radiologists in consensus analyzed catheters and cardiovascular, parenchymal, and pleural findings. Clinical reports and study review were compared for substantial differences in findings that could have led to a treatment change, triggered additional examinations such as bronchoscopy, or were considered important for donation.Results: Among 136 bedside chest radiographs, no differences between clinical reports and study reviews were found in 37 (27%), minor differences were found in 28 (21%), and substantial differences were found in 71 (52%) examinations (P<0.0001). In 31 of 42 (74%) complete or incomplete CT examinations, 50 of 74 findings with relevance for lung donation were not primarily reported (P<0.0001).Conclusions: The majority of donor patients undergo only chest radiography. A targeted imaging review of abnormalities affecting the decision to use donor lungs may be useful in the preoperative stage. With a targeted list, substantial changes were made from initial clinical interpretations. CT can provide valuable information on donor lung pathology, even if the lungs are only partially imaged.
  •  
26.
  • Bozovic, Gracijela, et al. (författare)
  • Impact of donor chest radiography on clinical outcome after lung transplantation
  • 2018
  • Ingår i: Acta Radiologica Open. - : SAGE Publications. - 2058-4601. ; 7:6
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundOrgan donation guidelines recommend a “clear” conventional bedside chest radiograph before lung transplantation despite only moderate accuracy for cardiopulmonary abnormalities.PurposeTo evaluate the influence of donor image interpretation on lung transplantation outcome in recipients by following early and late complications, one-year survival, and to correlate imaging findings and blood gas analysis with lung transplantation outcome in recipients.Material and MethodsIn 35 lung donors from a single institution clinical reports and study reviews of imaging findings of the mandatory bedside chest radiographs and blood gas analyses were compared with clinical outcome in 38 recipients. Hospitalization time, peri- and postoperative complications, early complications (primary graft dysfunction, infection), 30-day and one-year survival, and forced expiratory volume in 1 s percentage of predicted normal value (FEV1%) at one-year follow-up were analyzed.ResultsFindings in clinical reports and study reviews differed substantially, e.g. regarding reported decompensation, edema, infection, and atelectasis. No correlation was shown between imaging findings in clinical report or study review and blood gas analyses in the lung donors compared to postoperative outcome in recipients.ConclusionThe interpretation of the mandatory chest radiograph in its present form does not influence one-year outcome in lung transplantation. Larger imaging studies or a change in clinical routine including computed tomography may provide evidence for future guidelines.
  •  
27.
  • Brännmark, Cecilia, et al. (författare)
  • FIND Stroke Recovery Study (FIND): rationale and protocol for a longitudinal observational cohort study of trajectories of recovery and biomarkers poststroke
  • 2023
  • Ingår i: Bmj Open. - 2044-6055. ; 13:5
  • Tidskriftsartikel (refereegranskat)abstract
    • ntroduction Comprehensive studies mapping domain-specific trajectories of recovery after stroke and biomarkers reflecting these processes are scarce. We, therefore, initiated an exploratory prospective observational study of stroke cases with repeated evaluation, the FIND Stroke Recovery Study. We aim to capture trajectories of recovery from different impairments, including cognition, in combination with broad profiling of blood and imaging biomarkers of the recovery. Methods and analysis We recruit individuals with first-ever stroke at the stroke unit at the Sahlgrenska University Hospital, Sweden, to FIND. The inclusion started early 2018 and we aim to enrol minimum 500 patients. Neurological and cognitive impairments across multiple domains are assessed using validated clinical assessment methods, advanced neuroimaging is performed and blood samples for biomarker measuring (protein, RNA and DNA) at inclusion and follow-up visits at 3 months, 6 months, 1 year, 2 years and 5 years poststroke. At baseline and at each follow-up visit, we also register clinical variables known to influence outcomes such as prestroke functioning, stroke severity, acute interventions, rehabilitation, other treatments, socioeconomic status, infections (including COVID-19) and other comorbidities. Recurrent stroke and other major vascular events are identified continuously in national registers. Ethics and dissemination FIND composes a unique stroke cohort with detailed phenotyping, repetitive assessments of outcomes across multiple neurological and cognitive domains and patient-reported outcomes as well as blood and imaging biomarker profiling. Ethical approval for the FIND study has been obtained from the Regional Ethics Review Board in Gothenburg and the Swedish Ethics Review Board. The results of this exploratory study will provide novel data on the time course of recovery and biomarkers after stroke. The description of this protocol will inform the stroke research community of our ongoing study and facilitate comparisons with other data sets.
  •  
28.
  • Corell, Alba, et al. (författare)
  • Spinal cord compression in relation to clinical symptoms in patients with spinal meningiomas.
  • 2021
  • Ingår i: Clinical neurology and neurosurgery. - : Elsevier BV. - 1872-6968 .- 0303-8467. ; 211
  • Tidskriftsartikel (refereegranskat)abstract
    • Spinal meningiomas are common primary tumors of the spinal canal and the resulting spinal cord compression (SCC) is intrinsically related to symptoms and outcome, but literature concerning this association is limited. We aimed to present data on both degree of SCC and tumor occupancy percentage in relation to neurological symptoms and outcome.Patients ≥18 years with a histological diagnosis of spinal canal meningioma treated between 2000 and 2017 were retrospectively evaluated for symptoms and neurological outcome in relation to SCC (i.e. compression of spinal cord at maximal tumor compression compared to maximum area above/below compression) and tumor occupancy percentage (percentage of dural sac area occupied by tumor at maximal tumor compression). Area segmentation of spinal cord, tumor and dural sac (as marker of spinal canal) was performed manually on magnetic resonance imaging (MRI) scans. The neurological deficit was assessed pre- and postoperatively according to the McCormick score. A logistic regression was made with a training set to identify the cut-off level for motor deficit.The cohort included 111 patients with a mean age of 62.5 years and 77.5% were female. The dominating symptoms preoperatively were sensory disturbance (91.0%), motor deficit (80.2%) and gait disturbance (67.6%). Postoperatively 53.2% of patients, also in some of those with severe deficit and high tumor occupancy, improved their neurological deficit and 43.2% were unchanged. Patients with intradural meningioma and assessable MRI scans were included to evaluate SCC (n=83). The mean extent of SCC was 50.6%. Exploration of tumor occupancy percentage identified a cut-off at 65% tumor occupancy to best discriminate between patients with or without motor deficit.Patients with an intradural tumor occupancy percentage of >65% are more likely to have a preoperative symptom and deficit, validating previous findings. Therefore, we suggest that even in asymptomatic, otherwise fit, patients with tumor occupancy approaching 65% should be considered for surgery since there is a high risk of developing deficit with even minimal growth. Concerning recovery, patients with tumor both high tumor occupancy and significantly impaired function tended to improve their functional level postoperatively.
  •  
29.
  • Corell, Alba, et al. (författare)
  • The clinical significance of the T2-FLAIR mismatch sign in grade II and III gliomas: a population-based study.
  • 2020
  • Ingår i: BMC cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 20:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The T2-FLAIR mismatch sign is an imaging finding highly suggestive of isocitrate dehydrogenase mutated (IDH-mut) 1p19q non-codeleted (non-codel) gliomas (astrocytomas). In previous studies, it has shown excellent specificity but limited sensitivity for IDH-mut astrocytomas. Whether the mismatch sign is a marker of a clinically relevant subtype of IDH-mut astrocytomas is unknown.We included histopathologically verified supratentorial lower-grade gliomas (LGG) WHO grade II-III retrospectively during the period 2010-2016. In the period 2017-2018, patients with suspected LGG radiologically were prospectively included, and in this cohort other diagnoses than glioma could occur. Clinical, radiological and molecular data were collected. For clinical evaluation we included all patients with IDH-mut astrocytomas. In the 2010-2016 cohort DNA methylation analysis with Infinium MethylationEPIC BeadChip (Illumina) was performed for patients withan IDH-mut astrocytomawith available tissue. We aimed to examine the association of the T2-FLAIRmismatch sign with clinical factors and outcomes. Additionally, we evaluated the diagnostic reliability of the mismatch sign and its relation to methylation profiles.Out of 215 patients with LGG, 135 had known IDH-mutation and 1p19q codeletion status. Fifty patients hadan IDH-mut astrocytoma and 12 of these (24.0%) showed a mismatch sign. The sensitivity and specificity of the mismatch sign for IDH-mut detection were 26.4 and 97.6%, respectively. There were no differences between patients withan IDH-mut astrocytoma with or without mismatch sign when grouped according to T2-FLAIR mismatch sign with respect to baseline characteristics, clinical outcomes and methylation profiles. The overall interrater agreement between neuroradiologist and clinical neurosurgeons for the T2-FLAIR mismatch sign was significant when all 215 MRI examination assessed (κ=0.77, p<0.001, N=215).The T2-FLAIR mismatch sign in patients withan IDH-mut astrocytoma is not associated with clinical presentation or outcome. It seems unlikely that the IDH-mut astrocytomas with mismatch sign represent a specific subentity. Finally, we have validated that the T2-FLAIR mismatch sign is a reliable and specific marker of IDH-mut astrocytomas.
  •  
30.
  • de Dios, Eddie, 1987, et al. (författare)
  • Comparison of the patient-derived modified Japanese Orthopaedic Association scale and the European myelopathy score
  • 2024
  • Ingår i: European Spine Journal. - : SPRINGER. - 0940-6719 .- 1432-0932. ; 33:3, s. 1205-1212
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To compare the patient-derived modified Japanese Orthopaedic Association (P-mJOA) scale with the European myelopathy score (EMS) for the assessment of patients with degenerative cervical myelopathy (DCM). Methods: In this register-based cohort study with prospectively collected data, included patients were surgically treated for DCM and had reported both P-mJOA and EMS scores at baseline, 1-year follow-up, and/or 2-year follow-up to the Swedish Spine Register. P-mJOA and EMS scores were defined as severe (P-mJOA 0–11 and EMS 5–8), moderate (P-mJOA 12–14 and EMS 9–12), or mild (P-mJOA 15–18 and EMS 13–18). P-mJOA and EMS mean scores were compared, and agreement was evaluated with Spearman’s rank correlation coefficient (ρ), the intraclass correlation coefficient (ICC), and kappa (κ) statistics. Results: Included patients (n = 714, mean age 63.2years, 42.2% female) completed 937 pairs of the P-mJOA and the EMS. The mean P-mJOA and EMS scores were 13.9 ± 3.0 and 14.5 ± 2.7, respectively (mean difference –0.61 [95% CI –0.72 to –0.51; p < 0.001]). Spearman’s ρ was 0.84 (p < 0.001), and intra-rater agreement measured with ICC was 0.83 (p < 0.001). Agreement of severity level measured with unweighted and weighted κ was fair (κ = 0.22 [p < 0.001]; κ = 0.34 [p < 0.001], respectively). Severity levels were significantly higher using the P-mJOA (p < 0.001). Conclusion: The P-mJOA and the EMS had similar mean scores, and intra-rater agreement was high, whereas severity levels only demonstrated fair agreement. The EMS has a lower sensitivity for detecting severe myelopathy but shows an increasing agreement with the P-mJOA for milder disease severity. A larger interval to define severe myelopathy with the EMS is recommended.
  •  
31.
  • de Dios, Eddie, 1987, et al. (författare)
  • Improvement rates, adverse events and predictors of clinical outcome following surgery for degenerative cervical myelopathy
  • 2022
  • Ingår i: European Spine Journal. - : Springer Science and Business Media LLC. - 0940-6719 .- 1432-0932. ; 31:12, s. 3433-3442
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To investigate improvement rates, adverse events and predictors of clinical outcome after laminectomy alone (LAM) or laminectomy with instrumented fusion (LAM + F) for degenerative cervical myelopathy (DCM). Methods: This is a post hoc analysis of a previously published DCM cohort. Improvement rates for European myelopathy score (EMS) and Neck Disability Index (NDI) at 2- and 5-year follow-ups and adverse events are presented descriptively for available cases. Predictor endpoints were EMS and NDI scores at follow-ups, surgeon- and patient-reported complications, and reoperation-free interval. For predictors, univariate and multivariable models were fitted to imputed data. Results: Mean age of patients (LAM n = 412; LAM + F n = 305) was 68years, and 37.4% were women. LAM + F patients had more severe spondylolisthesis and less severe kyphosis at baseline, more surgeon-reported complications, more patient-reported complications, and more reoperations (p ≤ 0.05). After imputation, the overall EMS improvement rate was 43.8% at 2years and 36.3% at 5years. At follow-ups, worse EMS scores were independent predictors of worse EMS outcomes and older age and worse NDI scores were independent predictors of worse NDI outcomes. LAM + F was associated with more surgeon-reported complications (ratio 1.81; 95% CI 1.17–2.80; p = 0.008). More operated levels were associated with more patient-reported complications (ratio 1.12; 95% CI 1.02–1.22; p = 0.012) and a shorter reoperation-free interval (hazard ratio 1.30; 95% CI 1.08–1.58; p = 0.046). Conclusions: These findings suggest that surgical intervention at an earlier myelopathy stage might be beneficial and that less invasive procedures are preferable in this patient population.
  •  
32.
  • de Dios, Eddie, 1987, et al. (författare)
  • MRI-based measurements of spondylolisthesis and kyphosis in degenerative cervical myelopathy.
  • 2023
  • Ingår i: BMC medical imaging. - : BioMed Central (BMC). - 1471-2342. ; 23:1
  • Tidskriftsartikel (refereegranskat)abstract
    • To provide normative data and to determine accuracy and reliability of preoperative measurements of spondylolisthesis and kyphosis on supine static magnetic resonance imaging (MRI) of patients with degenerative cervical myelopathy.T2-weighted midsagittal images of the cervical spine were in 100 cases reviewed twice by one junior observer, with an interval of 3 months, and once by a senior observer. The spondylolisthesis slip (SSlip, mm) and the modified K-line interval (mK-line INT, mm) were assessed for accuracy with the standard error of measurement (SEm) and the minimum detectable change (MDC). Intraobserver and interobserver reliability levels were determined using the intraclass correlation coefficient (ICC).The SEm was 0.5mm (95% CI 0.4-0.6) for spondylolisthesis and 0.6mm (95% CI 0.5-0.7) for kyphosis. The MDC, i.e., the smallest difference between two examinations that can be detected with statistical certainty, was 1.5mm (95% CI 1.2-1.8) for spondylolisthesis and 1.6mm (95% CI 1.3-1.8) for kyphosis. The highest reliability levels were seen between the second observation of the junior examiner and the senior observer (ICC=0.80 [95% CI 0.70-0.87] and ICC=0.96 [95% CI 0.94-0.98] for SSlip and mK-line INT, respectively).This study provides normative values of alignment measurements of spondylolisthesis and kyphosis in DCM patients. It further shows the importance of taking measurement errors into account when defining cut-off values for cervical deformity parameters and their potential clinical application in surgical decision-making.
  •  
33.
  • Durmo, Faris, et al. (författare)
  • Brain Tumor Characterization Using Multibiometric Evaluation of MRI
  • 2018
  • Ingår i: Tomography : a journal for imaging research. - : MDPI AG. - 2379-1381. ; 4:1, s. 14-25
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim was to evaluate volume, diffusion, and perfusion metrics for better presurgical differentiation between high-grade gliomas (HGG), low-grade gliomas (LGG), and metastases (MET). For this retrospective study, 43 patients with histologically verified intracranial HGG (n = 18), LGG (n = 10), and MET (n = 15) were chosen. Preoperative magnetic resonance data included pre- and post-gadolinium contrast-enhanced T1-weighted fluid-attenuated inversion recover, cerebral blood flow (CBF), cerebral blood volume (CBV), fractional anisotropy, and apparent diffusion coefficient maps used for quantification of magnetic resonance biometrics by manual delineation of regions of interest. A binary logistic regression model was applied for multiparametric analysis and receiver operating characteristic (ROC) analysis. Statistically significant differences were found for normalized-ADC-tumor (nADC-T), normalized-CBF-tumor (nCBF-T), normalized-CBV-tumor (nCBV-T), and normalized-CBF-edema (nCBF-E) between LGG and HGG, and when these metrics were combined, HGG could be distinguished from LGG with a sensitivity and specificity of 100%. The only metric to distinguish HGG from MET was the normalized-ADC-E with a sensitivity of 68.8% and a specificity of 80%. LGG can be distinguished from MET by combining edema volume (Vol-E), Vol-E/tumor volume (Vol-T), nADC-T, nCBF-T, nCBV-T, and nADC-E with a sensitivity of 93.3% and a specificity of 100%. The present study confirms the usability of a multibiometric approach including volume, perfusion, and diffusion metrics in differentially diagnosing brain tumors in preoperative patients and adds to the growing body of evidence in the clinical field in need of validation and standardization.
  •  
34.
  • Durmo, Faris, et al. (författare)
  • Multivoxel 1H-MR Spectroscopy Biometrics for Preoprerative Differentiation Between Brain Tumors
  • 2018
  • Ingår i: Tomography : a journal for imaging research. - : MDPI AG. - 2379-1381. ; 4:4, s. 172-181
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigated multivoxel proton magnetic resonance spectroscopy (1H-MRS) biometrics for preoperative differentiation and prognosis of patients with brain metastases (MET), low-grade glioma (LGG) and high-grade glioma (HGG). In total, 33 patients (HGG, 14; LGG, 9; and 10 MET) were included. 1H-MRS imaging (MRSI) data were assessed and neurochemical profiles for metabolites N-acetyl aspartate (NAA) + NAAG(NAA), Cr + PCr(total creatine, tCr), Glu + Gln(Glx), lactate (Lac), myo-inositol(Ins), GPC + PCho(total choline, tCho), and total lipids, and macromolecule (tMM) signals were estimated. Metabolites were reported as absolute concentrations or ratios to tCho or tCr levels. Voxels of interest in an MRSI matrix were labeled according to tissue. Logistic regression, receiver operating characteristic, and Kaplan-Meier survival analysis was performed. Across HGG, LGG, and MET, average Ins/tCho was shown to be prognostic for overall survival (OS): low values (≤1.29) in affected hemisphere predicting worse OS than high values (>1.29), (log rank < 0.007). Lip/tCho and Ins/tCho combined showed 100% sensitivity and specificity for both HGG/LGG (P < .001) and LGG/MET (P < .001) measured in nonenhancing/contrast-enhancing lesional tissue. Combining tCr/tCho in perilesional edema with tCho/tCr and NAA/tCho from ipsilateral normal- appearing tissue yielded 100% sensitivity and 81.8% specificity (P < .002) for HGG/MET. Best single biomarker: Ins/tCho for HGG/LGG and total lipid/tCho for LGG/MET showed 100% sensitivity and 75% and 100% specificity, respectively. HGG/MET; NAA/tCho showed 75% sensitivity and 84.6% specificity. Multivoxel 1H-MRSI provides prognostic information for OS for HGG/LGG/MET and a multibiometric approach for differentiation may equal or outperform single biometrics.
  •  
35.
  • Düzel, E., et al. (författare)
  • European Ultrahigh-Field Imaging Network for Neurodegenerative Diseases (EUFIND)
  • 2019
  • Ingår i: Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. - : Wiley. - 2352-8729. ; 11, s. 538-549
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: The goal of European Ultrahigh-Field Imaging Network in Neurodegenerative Diseases (EUFIND) is to identify opportunities and challenges of 7 Tesla (7T) MRI for clinical and research applications in neurodegeneration. EUFIND comprises 22 European and one US site, including over 50 MRI and dementia experts as well as neuroscientists. Methods: EUFIND combined consensus workshops and data sharing for multisite analysis, focusing on 7 core topics: clinical applications/clinical research, highest resolution anatomy, functional imaging, vascular systems/vascular pathology, iron mapping and neuropathology detection, spectroscopy, and quality assurance. Across these topics, EUFIND considered standard operating procedures, safety, and multivendor harmonization. Results: The clinical and research opportunities and challenges of 7T MRI in each subtopic are set out as a roadmap. Specific MRI sequences for each subtopic were implemented in a pilot study presented in this report. Results show that a large multisite 7T imaging network with highly advanced and harmonized imaging sequences is feasible and may enable future multicentre ultrahigh-field MRI studies and clinical trials. Discussion: The EUFIND network can be a major driver for advancing clinical neuroimaging research using 7T and for identifying use-cases for clinical applications in neurodegeneration. © 2018 The Authors
  •  
36.
  • Enström, Inger, et al. (författare)
  • Organ damage in treated middle-aged hypertensives compared to normotensives: results from a cross-sectional study in general practice
  • 2000
  • Ingår i: Blood Pressure. - : Informa UK Limited. - 0803-7051 .- 1651-1999. ; 9:1, s. 28-33
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: High blood pressure contributes to organ damage. However, during the past two decades there have been great advances in the medical treatment of hypertension. Technical progress has also made it easier to visualize organ damage. Hence we found it of interest to examine heart, brain and retina in a group of middle-aged treated hypertensives, comparing the results with those from a group of middle-aged normotensives. METHODS: The subjects were 40 (20 men) treated hypertensives and 40 (20 men) normotensives, who had previously taken part in a study in which ambulatory blood pressure monitoring had been performed. The heart was examined by echocardiography, the retina by photography and the brain by magnetic resonance imaging. RESULTS: Office blood pressure and 24-h systolic/diastolic blood pressure (S/D) were 141/86 (13/7) mmHg and 128/81 (11/6) mmHg in the hypertensives and 125/78 (10/8) mmHg and 118/74 (8/5) mmHg in the normotensives, respectively. Left ventricular mass was 101 (27) g/m2 in the hypertensives and 85 (18) g/m2 in the normotensives (p = 0.0025). The corresponding figures for the left atrium were 21.1 (3.1) mm/m2 in the hypertensives and 19.5 (2.2) mm/m2 in the normotensives (p < 0.001). E/A wave quotient was 1.09 (0.26) in the hypertensives and 1.26 (0.26) in the normotensives (p = 0.0045), while left ventricular systolic function did not differ between the groups. Ten hypertensives and one normotensive subject had left ventricular mass above normal range. Narrow retinal arteries were found in 22 hypertensives and 8 normotensives (p < 0.001). Brain magnetic resonance changes (deep white matter and/or periventricular) were found in 19 hypertensives and 9 normotensives (p = 0.0431). CONCLUSIONS: The hypertensives differed significantly from the normotensives concerning left ventricular mass, left atrium, left ventricular diastolic function and retinal vessel changes. Deep white matter and periventricular changes in the brain were also significantly different in the two groups. We can only speculate as to whether earlier antihypertensive treatment or further blood pressure reduction could have affected these differences.
  •  
37.
  • Fagan, A. J., et al. (författare)
  • 7T MR Safety
  • 2021
  • Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807 .- 1522-2586. ; 53:2333-346, s. 333-346
  • Tidskriftsartikel (refereegranskat)abstract
    • Magnetic resonance imaging and spectroscopy (MRI/MRS) at 7T represents an exciting advance in MR technology, with intriguing possibilities to enhance image spatial, spectral, and contrast resolution. To ensure the safe use of this technology while still harnessing its potential, clinical staff and researchers need to be cognizant of some safety concerns arising from the increased magnetic field strength and higher Larmor frequency. The higher static magnetic fields give rise to enhanced transient bioeffects and an increased risk of adverse incidents related to electrically conductive implants. Many technical challenges remain and the continuing rapid pace of development of 7T MRI/MRS is likely to present further challenges to ensuring safety of this technology in the years ahead. The recent regulatory clearance for clinical diagnostic imaging at 7T will likely increase the installed base of 7T systems, particularly in hospital environments with little prior ultrahigh-field MR experience. Informed risk/benefit analyses will be required, particularly where implant manufacturer-published 7T safety guidelines for implants are unavailable. On behalf of the International Society for Magnetic Resonance in Medicine, the aim of this article is to provide a reference document to assist institutions developing local institutional policies and procedures that are specific to the safe operation of 7T MRI/MRS. Details of current 7T technology and the physics underpinning its functionality are reviewed, with the aim of supporting efforts to expand the use of 7T MRI/MRS in both research and clinical environments. Current gaps in knowledge are also identified, where additional research and development are required. Level of Evidence 5 Technical Efficacy 2
  •  
38.
  • Finnsson, Johannes, 1979- (författare)
  • Radiological studies of LMNB1-related autosomal dominant leukodystrophy and Marinesco-Sjögren syndrome
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • There are approximately 6000 to 8000 rare diseases, each with a prevalence of less than 1 / 10 000, but in aggregate affecting 6 to 8% of the population. It is important to evaluate disease development and progression to know the natural course of any disease. This information can be utilized in diagnostics and in assessing effects of therapeutic interventions as they become available. This thesis describes the natural clinical history and evolution of imaging findings of two rare diseases over approximately two decades.Papers I, II and III present clinical, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS) and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) findings in LMNB1-related autosomal dominant leukodystrophy (ADLD). MRI was found to be very sensitive in finding pathology in patients with LMNB1-related ADLD, even before the onset of clinical symptoms. However, even patients with widespread MRI changes can have a relatively mild symptomatology and present only slight disturbances in metabolic examinations such as MRS and FDG-PET. This is compatible with relatively intact axons, even as myelin impairment is widespread.Paper IV presents clinical and MRI findings in the brain and musculature in SIL1-positive Marinesco-Sjögren syndrome (MSS), and describes a new, mild phenotype of the disease with no intellectual disabilities and only slight motor disabilities. With a 19-year-long radiological follow-up, a slow progressive atrophic process in the cerebellum and brainstem could be demonstrated. MRI of the musculature shows early involvement of the quadriceps and gastrocnemii but not the tibialis anterior, progressing to widespread atrophy in the back and upper and lower limbs at the age of 20 years. In the mildest phenotype, the most severely affected muscles were the m gluteus maximus, m sartorius, m peroneus longus, and the lateral head of the m gastrocnemius.
  •  
39.
  • Follin, Cecilia, et al. (författare)
  • Associations between Metabolic Risk Factors and the Hypothalamic Volume in Childhood Leukemia Survivors Treated with Cranial Radiotherapy.
  • 2016
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Metabolic complications are prevalent in individuals treated with cranial radiotherapy (CRT) for childhood acute lymphoblastic leukemia (ALL). The hypothalamus is a master regulator of endocrine and metabolic control. The aim of this study was to investigate whether the hypothalamic volume would be associated to metabolic parameters in ALL survivors. Thirty-eight (21 women) survivors participated in this study 34 years after diagnosis and with a median age of 38 (27-46) years. All were treated with a median CRT dose of 24 Gy and 11 years (3-13) of complete hormone supplementation. Comparisons were made to 31 matched controls. We performed analyses of fat mass, fat free mass, plasma (p)-glucose, p-insulin, Homa-Index (a measure of insulin resistance), serum (s)-leptin, s-ghrelin and of the hypothalamic volume in scans obtained by magnetic resonance imaging (MRI) at 3 Tesla. Serum leptin/kg fat mass (r = -0.4, P = 0.04) and fat mass (r = -0.4, P = 0.01) were negatively correlated with the HT volume among ALL survivors, but not among controls. We also detected significantly higher BMI, waist, fat mass, p-insulin, Homa-Index, leptin/kg fat mass and s-ghrelin and significantly lower fat free mass specifically among female ALL survivors (all P<0.01). Interestingly, s-ghrelin levels increased with time since diagnosis and with low age at diagnosis for childhood ALL. Our results showed that leptin/kg fat mass and fat mass were associated with a reduced HT volume 34 years after ALL diagnosis and that women treated with CRT after ALL are at high risk of metabolic abnormalities. Taken together our data suggest that the hypothalamus is involved in the metabolic consequences after CRT in ALL survivors.
  •  
40.
  • Follin, Cecilia, et al. (författare)
  • Impaired brain metabolism and neurocognitive function in childhood leukemia survivors despite complete hormone supplementation in adulthood
  • 2016
  • Ingår i: Psychoneuroendocrinology. - : Elsevier BV. - 0306-4530 .- 1873-3360. ; 73, s. 157-165
  • Tidskriftsartikel (refereegranskat)abstract
    • Cranial radiotherapy is a known risk factor for neurocognitive impairment in survivors of childhood acute lymphoblastic leukemia (ALL). Understanding the nature of cognitive dysfunction during adulthood in ALL survivors is important as it has an impact on major life situations. Thirty-eight (21 women) ALL survivors were investigated 34 years after diagnosis. Median-age was 38 (27–46) years. All were treated with a CRT dose of 24 Gy and 11 years (3–13) of complete hormone supplementation. Comparisons were made to 29 matched controls. Assessments of magnetic resonance spectroscopy (white and grey matter metabolic alterations), brain volume and neuropsychological tests were performed. ALL survivors demonstrate a generally lower performance in neuropsychological tests. ALL survivors scored lower than controls in vocabulary (p < 0.001), memory (p < 0.001), learning capacity (p < 0.001), spatial ability (p < 0.001), executive functions and attention (p < 0.001) 34 years after ALL treatment. Compared to controls ALL survivors had reduced white matter (WM) (492 vs 536 cm3, p < 0.001) and grey matter (GM) volumes (525 vs 555 cm3, p = 0.001). ALL survivors had lower levels of WM N-acetyl aspartate/creatin (NAA/Cr) (1.48 vs 1.63, p = 0.004), WM NAA + NAAG (N-acetylaspartylglutamate)/Cr (1.61 vs 1.85, p < 0.001) and lower levels of GM NAA/Cr (1.18 vs 1.30, p = 0.001) and GM NAA + NAAG/Cr (1.28 vs 1.34, p = 0.01) compared to controls. ALL survivors had higher levels in WM MI (Myoinositol)/NAA (0.65 vs 0.56, p = 0.01) concentrations compared to controls. There was a significantly negative correlation of years since ALL diagnosis to WM NAA + NAAG/Cr (r = −0.4, p = 0.04) in ALL survivors. The present study shows impaired brain metabolism detected by MRS, reduced brain volumes and neurocognitive impairment in childhood ALL survivors treated with cranial radiotherapy and chemotherapy, despite complete hormone substitution. We also report an impairment of metabolites correlated to time since treatment and a progressive impairment in sustained attention, suggesting an accelerated aging in the irradiated brain. Following these survivors many decades, or throughout life, after treatment with cranial radiotherapy and chemotherapy is highly warranted for a broader understanding of long-term outcome in this patient group.
  •  
41.
  • Follin, Cecilia, et al. (författare)
  • Microstructural white matter alterations associated to neurocognitive deficits in childhood leukemia survivors treated with cranial radiotherapy–a diffusional kurtosis study
  • 2019
  • Ingår i: Acta Oncologica. - 0284-186X. ; 58:7, s. 1021-1028
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Cranial radiotherapy (CRT) is a known risk factor for neurocognitive impairment in survivors of childhood acute lymphoblastic leukemia (ALL). Diffusion tensor imaging (DTI) and diffusional kurtosis imaging (DKI) are MRI techniques that quantify microstructural changes in brain white matter (WM) and DKI is regarded as the more sensitive of them. Our aim was to more thoroughly understand the nature of cognitive deficits after cranial radiotherapy (CRT) in adulthood after childhood ALL. Material and methods: Thirty-eight (21 women) ALL survivors, median age 38 (27–46) years, were investigated at median 34 years after diagnosis. All had been treated with a CRT dose of 24 Gy and with 11 years of complete hormone supplementation. DTI and DKI parameters were determined and neurocognitive tests were performed in ALL survivors and 29 matched controls. Results: ALL survivors scored lower than controls in neurocognitive tests of vocabulary, memory, learning capacity, spatial ability, executive functions, and attention (p <.001). The survivors had altered DTI parameters in the fornix, uncinate fasciculus, and ventral cingulum (all p <.05) and altered DKI parameters in the fornix, uncinate fasciculus, and dorsal and ventral cingulum (p <.05). Altered DTI parameters in the fornix were associated with impaired episodic verbal memory (r = −0.40, p <.04). The left and right uncinate fasciculus (r = 0.6, p <.001), (r = −0.5, p <.02) as well as the right ventral cingulum (r = 0.5, p <.007) were associated with impaired episodic visual memory. Altered DKI parameters in the fornix, right uncinate fasciculus (r = 0.3, r = 0.05, p =.02), and ventral cingulum (r = 0.3, p =.02) were associated with impaired results of episodic visual memory. Conclusion: ALL survivors with cognitive deficits demonstrated microstructural damage in several WM tracts that were more extensive with DKI as compared to DTI; this might be a marker of radiation and chemotherapy neurotoxicity underlying cognitive dysfunction.
  •  
42.
  •  
43.
  • Fällmar, David, et al. (författare)
  • [Conditions for performing CT and MRI scans in pregnant and lactating patients]. : Att tänka på vid neuroradiologisk diagnostik av gravida och ammande.
  • 2023
  • Ingår i: Lakartidningen. - 1652-7518. ; 120
  • Tidskriftsartikel (refereegranskat)abstract
    • Many women are pregnant during several percent of their lives. Occasionally, there is a need for neuroradiological examinations during pregnancy or lactation. In our clinical work, we regularly see that female patients are being withheld relevant diagnostic scans during pregnancy, due to insufficient knowledge or an unbalanced comparison between benefits and risks. This article describes the current knowledge regarding conditions for performing CT and MRI scans in pregnant and lactating patients, including the use of contrast media. PET scans and reactions to contrast media are briefly mentioned, but interventional radiology is not discussed.
  •  
44.
  • Gard, Anna, et al. (författare)
  • Post-Concussive Vestibular Dysfunction Is Related to Injury to the Inferior Vestibular Nerve
  • 2022
  • Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 39:11-12
  • Tidskriftsartikel (refereegranskat)abstract
    • Symptoms of vestibular dysfunction such as dizziness and vertigo are common after sports-related concussions (SRC) and associated with a worse outcome and a prolonged recovery. Vestibular dysfunction after SRC can be because of an impairment of the peripheral or central neural parts of the vestibular system. The aim of the present study was to establish the cause of vestibular impairment in athletes with SRC who have persisting post-concussive symptoms (PPCS). We recruited 42 participants-21 athletes with previous SRCs and PPCS >= 6 months and 21 healthy athletic age- and sex-matched controls-who underwent symptom rating, a detailed test battery of vestibular function and 7T magnetic resonance imaging with diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) of cerebellar white matter tracts, and T1-weighted imaging for cerebellar volumetrics. Vestibular dysfunction was observed in 13 SRC athletes and three controls (p = 0.001). Athletes with vestibular dysfunction reported more pronounced symptoms on the Dizziness Handicap Inventory (DHI; p < 0.001) and the Hospital Anxiety and Depression Scale (HADS; p < 0.001). No significant differences in DTI metrics were found, while in DKI two metrics were observed in the superior and/or inferior cerebellar tracts. Cerebellar gray and white matter volumes were similar in athletes with SRC and controls. Compared with controls, pathological video head impulse test results (vHIT; p < 0.001) and cervical vestibular evoked myogenic potentials (cVEMP; p = 0.002) were observed in athletes with SRC, indicating peripheral vestibular dysfunction and specifically suggesting injury to the inferior vestibular nerve. In athletes with persisting symptoms after SRC, vestibular dysfunction is associated with injury to the inferior vestibular nerve.
  •  
45.
  • Gard, Anna, et al. (författare)
  • Widespread White Matter Abnormalities in Concussed Athletes Detected by 7T Diffusion Magnetic Resonance Imaging
  • 2024
  • Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc.. - 0897-7151 .- 1557-9042.
  • Tidskriftsartikel (refereegranskat)abstract
    • Sports-related concussions may cause white matter injuries and persistent post-concussive symptoms (PPCS). We hypothesized that athletes with PPCS would have neurocognitive impairments and white matter abnormalities that could be revealed by advanced neuroimaging using ultra-high field strength diffusion tensor (DTI) and diffusion kurtosis (DKI) imaging metrics and cerebrospinal fluid (CSF) biomarkers. A cohort of athletes with PPCS severity limiting the ability to work/study and participate in sport school and/or social activities for ≥6 months completed 7T magnetic resonance imaging (MRI) (morphological T1-weighed volumetry, DTI and DKI), extensive neuropsychological testing, symptom rating, and CSF biomarker sampling. Twenty-two athletes with PPCS and 22 controls were included. Concussed athletes performed below norms and significantly lower than controls on all but one of the psychometric neuropsychology tests. Supratentorial white and gray matter, as well as hippocampal volumes did not differ between concussed athletes and controls. However, of the 72 examined white matter tracts, 16% of DTI and 35% of DKI metrics (in total 28%) were significantly different between concussed athletes and controls. DKI fractional anisotropy and axial kurtosis were increased, and DKI radial diffusivity and radial kurtosis decreased in concussed athletes when compared with controls. CSF neurofilament light (NfL; an axonal injury marker), although not glial fibrillary acidic protein, correlated with several diffusion metrics. In this first 7T DTI and DKI study investigating PPCS, widespread microstructural alterations were observed in the white matter, correlating with CSF markers of axonal injury. More white matter changes were observed using DKI than using DTI. These white matter alterations may indicate persistent pathophysiological processes following concussion in sport.
  •  
46.
  • Glans, Anton, et al. (författare)
  • Health effects related to exposure of static magnetic fields and acoustic noise-comparison between MR and CT radiographers
  • 2022
  • Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 32, s. 7896-7909
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives We explored the prevalence of health complaints subjectively associated with static magnetic field (SMF) and acoustic noise exposure among MR radiographers in Sweden, using CT radiographers as a control group. Additionally, we explored radiographers' use of strategies to mitigate adverse health effects. Methods A cross-sectional survey was sent to all hospitals with MR units in Sweden. MR and/or CT personnel reported prevalence and attribution of symptoms (vertigo/dizziness, nausea, metallic taste, illusion of movement, ringing sensations/tinnitus, headache, unusual drowsiness/tiredness, forgetfulness, difficulties concentrating, and difficulties sleeping) within the last year. We used logistic regression to test associations between sex, age, stress, SMF strength, working hours, and symptom prevalence. Data regarding hearing function, work-environmental noise, and strategies to mitigate adverse symptoms were also analysed. Results In total, 529 out of 546 respondents from 86 hospitals were eligible for participation. A >= 20 working hours/week/modality cut-off rendered 342 participants grouped into CT (n = 75), MR (n = 121), or mixed personnel (n = 146). No significant differences in symptom prevalence were seen between groups. Working at >= 3T increased SMF-associated symptoms as compared with working at <= 1.5T (OR: 2.03, CI95: 1.05-3.93). Stress was a significant confounder. Work-related noise was rated as more troublesome by CT than MR personnel (p < 0.01). MR personnel tended to use more strategies to mitigate adverse symptoms. Conclusion No significant differences in symptom prevalence were seen between MR and CT radiographers. However, working at 3T increased the risk of SMF symptoms, and stress increased adverse health effects. Noise nuisance was considered more problematic by CT than MR personnel.
  •  
47.
  • Gryska, Emilia, 1992, et al. (författare)
  • Automatic brain lesion segmentation on standard magnetic resonance images: a scoping review.
  • 2021
  • Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Medical image analysis practices face challenges that can potentially be addressed with algorithm-based segmentation tools. In this study, we map the field of automatic MR brain lesion segmentation to understand the clinical applicability of prevalent methods and study designs, as well as challenges and limitations in the field.Scoping review.Three databases (PubMed, IEEE Xplore and Scopus) were searched with tailored queries. Studies were included based on predefined criteria. Emerging themes during consecutive title, abstract, methods and whole-text screening were identified. The full-text analysis focused on materials, preprocessing, performance evaluation and comparison.Out of 2990 unique articles identified through the search, 441 articles met the eligibility criteria, with an estimated growth rate of 10% per year. We present a general overview and trends in the field with regard to publication sources, segmentation principles used and types of lesions. Algorithms are predominantly evaluated by measuring the agreement of segmentation results with a trusted reference. Few articles describe measures of clinical validity.The observed reporting practices leave room for improvement with a view to studying replication, method comparison and clinical applicability. To promote this improvement, we propose a list of recommendations for future studies in the field.
  •  
48.
  • Gryska, Emilia, 1992, et al. (författare)
  • Deep learning for automatic brain tumour segmentation on MRI: evaluation of recommended reporting criteria via a reproduction and replication study.
  • 2022
  • Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 12:7
  • Tidskriftsartikel (refereegranskat)abstract
    • To determine the reproducibility and replicability of studies that develop and validate segmentation methods for brain tumours on MRI and that follow established reproducibility criteria; and to evaluate whether the reporting guidelines are sufficient.Two eligible validation studies of distinct deep learning (DL) methods were identified. We implemented the methods using published information and retraced the reported validation steps. We evaluated to what extent the description of the methods enabled reproduction of the results. We further attempted to replicate reported findings on a clinical set of images acquired at our institute consisting of high-grade and low-grade glioma (HGG, LGG), and meningioma (MNG) cases.We successfully reproduced one of the two tumour segmentation methods. Insufficient description of the preprocessing pipeline and our inability to replicate the pipeline resulted in failure to reproduce the second method. The replication of the first method showed promising results in terms of Dice similarity coefficient (DSC) and sensitivity (Sen) on HGG cases (DSC=0.77, Sen=0.88) and LGG cases (DSC=0.73, Sen=0.83), however, poorer performance was observed for MNG cases (DSC=0.61, Sen=0.71). Preprocessing errors were identified that contributed to low quantitative scores in some cases.Established reproducibility criteria do not sufficiently emphasise description of the preprocessing pipeline. Discrepancies in preprocessing as a result of insufficient reporting are likely to influence segmentation outcomes and hinder clinical utilisation. A detailed description of the whole processing chain, including preprocessing, is thus necessary to obtain stronger evidence of the generalisability of DL-based brain tumour segmentation methods and to facilitate translation of the methods into clinical practice.
  •  
49.
  • Gujar, Sachin, et al. (författare)
  • Magnetic Resonance Spectroscopy.
  • 2005
  • Ingår i: Journal of Neuro-Ophthalmology. - 1070-8022. ; 25:3, s. 217-226
  • Tidskriftsartikel (refereegranskat)
  •  
50.
  • Hansson, Boel, et al. (författare)
  • Decrease of 7T MR short-term effects with repeated exposure
  • 2024
  • Ingår i: NEURORADIOLOGY. - 0028-3940 .- 1432-1920.
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose Although participants in 7 T magnetic resonance (MR) studies tolerate ultra-high field (UHF) well, subjectively experienced short-term effects, such as dizziness, inconsistent movement, nausea, or metallic taste, are reported. Evidence on subjectively experienced short-term effects in multiple exposures to UHF MR is scarce. The purpose of this study is to investigated experience of short-term effects, and occurrence of motion in healthy subjects exposed to seven weekly 7 T MR examinations.Methods A questionnaire on short-term effects was completed by participants in an fMRI motor skill study. Seven UHF MR examinations were conducted over 7 weeks (exposure number: 1 to 7). Changes of experienced short-term effects were analyzed. Motion in fMRI images was quantified.Results The questionnaire was completed 360 times by 67 participants after one to seven 7T MR examinations. Logistic mixed model analysis showed a significant association between dizziness, inconsistent movement, nausea, and headache and the examination numbers (p<0.03). Exposure to repeated examinations had no significant effect on peripheral nerve stimulation (PNS) or motion of the subjects. The overall experience of a 7T examination improved significantly (p<0.001) with increasing examination numbers.Conclusion During multiple 7T examinations, subjects adapt to the strong static field. The short-term effects dizziness, inconsistent movement, nausea, and headache decrease over time as the MR sessions continue and experienced comfort increases. There was no significant difference in motion during the multiple fMRI examinations.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 98
Typ av publikation
tidskriftsartikel (88)
konferensbidrag (4)
doktorsavhandling (2)
forskningsöversikt (2)
bokkapitel (2)
Typ av innehåll
refereegranskat (94)
övrigt vetenskapligt/konstnärligt (4)
Författare/redaktör
Björkman-Burtscher, ... (85)
Björkman-Burtscher, ... (14)
Holtås, Stig (12)
Siemund, Roger (12)
Björkman, Anders (9)
Nilsson, Markus (9)
visa fler...
Ståhlberg, Freddy (9)
Höglund, Peter (9)
Lätt, Jimmy (9)
Markenroth Bloch, Ka ... (8)
Sundgren, Pia C. (7)
van Westen, Danielle (7)
Löve, Askell (7)
Geijer, Mats (6)
Olsrud, Johan (6)
Källén, Kristina (5)
Heckemann, Rolf A. (5)
Vult von Steyern, Kr ... (5)
Laesser, Mats, 1969 (5)
Larsson, Elna-Marie (4)
Bozovic, Gracijela (4)
Englund, Elisabet (4)
Wirestam, Ronnie (4)
Knutsson, Linda (4)
Jakola, Asgeir Store (4)
Owman, Titti (4)
Geijer, Bo (4)
Blennow, Kaj, 1958 (3)
Zetterberg, Henrik, ... (3)
Hellström, Ann, 1959 (3)
Geijer, Mats, 1957 (3)
Sundgren, Pia (3)
Söderberg, Marcus (3)
Szczepankiewicz, Fil ... (3)
Hansson, Oskar (3)
Ley, David (3)
Schneiderman, Justin ... (3)
Erfurth, Eva Marie (3)
Lampinen, Björn (3)
Jalnefjord, Oscar, 1 ... (3)
Aurumskjöld, Marie-L ... (3)
Stålhammar, Fredrik (3)
Lindhagen, Lars (3)
Gryska, Emilia, 1992 (3)
Hoefling, Nickoleta (3)
Follin, Cecilia (3)
MacDowall, Anna (3)
Ramgren, Birgitta (3)
de Dios, Eddie, 1987 (3)
Wilén, Jonna (3)
visa färre...
Lärosäte
Lunds universitet (74)
Göteborgs universitet (41)
Uppsala universitet (9)
Karolinska Institutet (5)
Umeå universitet (3)
Luleå tekniska universitet (3)
visa fler...
Högskolan i Halmstad (1)
Stockholms universitet (1)
Örebro universitet (1)
Linköpings universitet (1)
Karlstads universitet (1)
visa färre...
Språk
Engelska (95)
Svenska (3)
Forskningsämne (UKÄ/SCB)
Medicin och hälsovetenskap (96)
Teknik (5)
Naturvetenskap (4)
Samhällsvetenskap (2)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy