| 1. |
|
|
| 2. |
- Brabec, Jan, et al.
(författare)
-
Histogram analysis of tensor-valued diffusion MRI in meningiomas : Relation to consistency, histological grade and type
- 2022
-
Ingår i: NeuroImage: Clinical. - : Elsevier BV. - 2213-1582. ; 33
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Preoperative radiological assessment of meningioma characteristics is of value for pre- and post-operative patient management, counselling, and surgical approach.PURPOSE: To investigate whether tensor-valued diffusion MRI can add to the preoperative prediction of meningioma consistency, grade and type.MATERIALS AND METHODS: 30 patients with intracranial meningiomas (22 WHO grade I, 8 WHO grade II) underwent MRI prior to surgery. Diffusion MRI was performed with linear and spherical b-tensors with b-values up to 2000 s/mm2. The data were used to estimate mean diffusivity (MD), fractional anisotropy (FA), mean kurtosis (MK) and its components-the anisotropic and isotropic kurtoses (MKA and MKI). Meningioma consistency was estimated for 16 patients during resection based on ultrasonic aspiration intensity, ease of resection with instrumentation or suction. Grade and type were determined by histopathological analysis. The relation between consistency, grade and type and dMRI parameters was analyzed inside the tumor ("whole-tumor") and within brain tissue in the immediate periphery outside the tumor ("rim") by histogram analysis.RESULTS: Lower 10th percentiles of MK and MKA in the whole-tumor were associated with firm consistency compared with pooled soft and variable consistency (n = 7 vs 9; U test, p = 0.02 for MKA 10 and p = 0.04 for MK10) and lower 10th percentile of MD with variable against soft and firm (n = 5 vs 11; U test, p = 0.02). Higher standard deviation of MKI in the rim was associated with lower grade (n = 22 vs 8; U test, p = 0.04) and in the MKI maps we observed elevated rim-like structure that could be associated with grade. Higher median MKA and lower median MKI distinguished psammomatous type from other pooled meningioma types (n = 5 vs 25; U test; p = 0.03 for MKA 50 and p = 0.03 and p = 0.04 for MKI 50).CONCLUSION: Parameters from tensor-valued dMRI can facilitate prediction of consistency, grade and type.
|
|
| 3. |
- Eliasson, Ann-Christin, 1950-, et al.
(författare)
-
The effectiveness of Baby-CIMT in infants younger than 12 months with clinical signs of unilateral-cerebral palsy : an explorative study with randomized design
- 2018
-
Ingår i: Research in Developmental Disabilities. - : Elsevier. - 0891-4222 .- 1873-3379. ; 72, s. 191-201
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: To explore the effectiveness of baby-CIMT (constraint-induced movement therapy) and baby-massage for improving the manual ability of infants younger than 12 months with unilateral cerebral palsy (CP).METHOD: Infants eligible for inclusion were 3-8 months old with asymmetric hand function and at high risk of developing unilateral CP. Thirty-seven infants were assigned randomly to receive baby-CIMT or baby-massage. At one year of age 31 children were diagnosed with unilateral CP, 18 (8 boys, 6.1±1.7months) of these had received baby-CIMT and 13 (8 boys, 5.0±1.6months) baby-massage. There were two 6-week training periods separated by a 6-week pause. The Hand Assessment for Infants (HAI), Assisting Hand Assessment (AHA), the Parenting Sense of Competence Scale (PSCS) and a questionnaire concerning feasibility were applied.RESULTS: There was improvement in the "Affected hand score" of HAI from median 10 (6;13 IQR) to 13 (7;17 IQR) raw score in the baby-CIMT group and from 5 (4;11 IQR) to 6 (3;12 IQR) for baby-massage with a significant between group difference (p=0.041). At 18-month of age, the median AHA score were 51 (38;72 IQR) after baby-CIMT (n=18) compared to 24 (19;43 IQR) baby-massage (n=9). The PSCS revealed an enhanced sense of competence of being a parent among fathers in the baby-CIMT group compared to fathers in the baby-massage (p=0.002). Parents considered both interventions to be feasible.CONCLUSION: Baby-CIMT appears to improve the unimanual ability of young children with unilateral CP more than massage.
|
|
| 4. |
- Erdi-Krausz, Gergo, et al.
(författare)
-
Neonatal hypoxic-ischaemic encephalopathy : Motor impairment beyond cerebral palsy
- 2021
-
Ingår i: European Journal of Paediatric Neurology. - : Elsevier BV. - 1090-3798. ; 35, s. 74-81
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Research investigating neuromotor function in the absence of cerebral palsy (CP) for children who had neonatal HIE is limited. Aims: To investigate school-age neurological and neuromotor function, and correlations with attention, neonatal Magnetic Resonance Imaging (MRI), and neuromotor assessments at toddler age. Methods: Twenty-seven children with neonatal HIE without CP who underwent hypothermia treatment and a comparison group of 20 children were assessed at age 5–7 years for Minor Neurological Dysfunction (MND; simplified Touwen), motor skills (Movement Assessment Battery for Children-2; MABC-2), parental concern over motor function (MABC Checklist), general cognition (Wechsler Preschool and Primary Scale of Intelligence-IV, WPPSI), and attention (DuPaul ADHD Rating Scale). Neurological examination and motor development, using Bayley-3 scales, at age 24-months was extracted from the clinical database. Clinical neonatal MRI was assessed for hypoxic-ischaemic injury. Results: In the HIE group, MND was more prevalent (p = 0.026) and M-ABC performance (total score p = 0.006; balance subtest p = 0.008) was worse; parents were more concerned about children's motor function (p = 0.011). HIE group inattention scores were higher (p = 0.032), which correlated with lower MABC-2 scores (rs = −0.590, p = 0.004). Neurological examination at 24-months correlated with MND (rs = 0.437, p = 0.033); Bayley-3 motor scores did not correlate with M-ABC-2 scores (rs = 368, p = 0.133). Neonatal MRI findings were not associated with school-age MND (rs = 0.140, p = 0.523) or MABC-2 (rs = 0.300, p = 0.165). Conclusions: Children with neonatal HIE, without CP, treated with hypothermia may be more likely to develop MND and motor difficulties than typically developing peers. Inattention may contribute to motor performance. In the absence of CP, neonatal MRI and toddler age assessment of motor development have limited predictive value for school-age outcome. Since this was an exploratory study with a small sample size, findings should be confirmed by a definite larger study.
|
|
| 5. |
- Jacobson, Lena, et al.
(författare)
-
Ganglion Cell Topography Indicates Pre- or Postnatal Damage to the Retro-Geniculate Visual System, Predicts Visual Field Function and May Identify Cerebral Visual Impairment in Children – A Multiple Case Study
- 2019
-
Ingår i: Neuro-Ophthalmology. - : Informa UK Limited. - 0165-8107 .- 1744-506X. ; 43:6, s. 363-370
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we quantify the degree of ganglion cell layer thinning due to retrograde trans-synaptic degeneration (RTSD) from retro-geniculate damage in six cases who had homonymous visual field defects known since childhood. Three had prenatal injuries, occurring close to mid-gestation and in the first parts of the early and late third trimester, respectively, and representing injuries at different early developmental stages. Three had later acquired injuries, at age 1.5, 4 and 13 years. The impact of the injury to the optic radiations was revealed by fibre tractography. The ganglion cell thinning corresponded with the visual field defects and the extent and location of the primary brain damage. The most important sign of RTSD was asymmetry of the ganglion cell topography within the macular area.
|
|
| 6. |
- Jacobson, Lena, et al.
(författare)
-
Retinal ganglion cell topography predicts visual field function in spastic cerebral palsy
- 2020
-
Ingår i: Developmental Medicine and Child Neurology. - : Wiley. - 0012-1622 .- 1469-8749. ; 62:9, s. 1100-1106
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the use of optical coherence tomography (OCT) to identify and assess visual field defects caused by primary damage to the optic radiation in individuals with spastic cerebral palsy (CP). Ten individuals with spastic CP (six females, four males, with a median age of 21 years [range 17–38y]) had their brain lesions documented with conventional magnetic resonance imaging (MRI) and diffusion-weighted MRI fibre tractography. Their macular ganglion cell layer (GCL) and inner plexiform layer (IPL) were examined with OCT and their visual fields were plotted. All participants had good visual acuity and were able to cooperate with the MRI and OCT examinations, as well as undergoing reliable perimetry. We found focal thinning of the GCL+IPL and corresponding homonymous visual field defects in individuals with brain damage affecting the optic radiation. We used GCL+IPL sector asymmetry as a sensitive OCT parameter to identify focal visual field defects. We observed no such sector asymmetry in GCL+IPL, or focal visual field defects, in individuals with normal MRI optic radiation imaging. Lesions affecting the optic radiation cause retrograde trans-synaptic degeneration of retinal ganglion cells. OCT examination of the GCL in the macula identified corresponding focal damage to the optic radiation in individuals with spastic CP and can be used to predict focal visual field defects. What this paper adds: Spastic cerebral palsy (CP) may be associated with damage to the optic radiation. Damage to the optic radiation causes retrograde trans-synaptic degeneration (RTSD). RTSD can be mapped using optical coherence tomography. Ganglion cell topography can predict visual field defects in individuals with spastic CP.
|
|
| 7. |
- Jungner, Åsa, et al.
(författare)
-
Perioperative brain injury marker concentrations in neonatal open-heart surgery: a prospective observational study
- 2023
-
Ingår i: Frontiers in Pediatrics. - 2296-2360. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Neonates with critical congenital heart defects undergoing open-heart surgery on cardiopulmonary bypass circulation are at risk for white matter brain injury. This article reports on pre- and postoperative plasma concentrations of brain injury markers glial fibrillary acidic protein (GFAP), neurofilament light (NfL) and Tau, and their respective associations with white matter lesions detected on postoperatively performed brain MRI. Forty term newborns with isolated critical congenital heart defects were included in a prospective observational study. Brain injury marker plasma concentrations were determined prior to surgery and at postoperative days 1, 2 and 3. Brain magnetic resonance imaging was performed pre- and postoperatively. Concentrations of brain injury markers were analysed using ultrasensitive single molecule array technology. Absolute pre- and postoperative plasma biomarker concentrations, and postoperative concentrations adjusted for preoperative concentrations were used for subsequent analysis. Plasma concentrations of GFAP, NfL and Tau displayed a well-defined temporal trajectory after neonatal cardiopulmonary bypass circulation. GFAP and Tau reached peak concentrations at postoperative day 2 (median concentrations 170.5 and 67.2 pg/ml, respectively), whereas NfL continued to increase throughout the study period (median concentration at postoperative day 3 191.5 pg/ml). Adjusted Tau at postoperative day 2 was significantly higher in infants presenting with white matter lesions on postoperative MRI compared to infants without white matter injury.
|
|
| 8. |
- Lennartsson, Finn, et al.
(författare)
-
Advanced fiber tracking in early acquired brain injury causing cerebral palsy
- 2015
-
Ingår i: American Journal of Neuroradiology. - : HighWire Press. - 0195-6108 .- 1936-959X. ; 36:1, s. 181-187
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Diffusion-weighted MR imaging and fiber tractography can be used to investigate alterations in white matter tracts in patients with early acquired brain lesions and cerebral palsy. Most existing studies have used diffusion tensor tractography, which is limited in areas of complex fiber structures or pathologic processes. We explored a combined normalization and probabilistic fiber-tracking method for more realistic fiber tractography in this patient group.MATERIALS AND METHODS: This cross-sectional study included 17 children with unilateral cerebral palsy and 24 typically developing controls. DWI data were collected at 1.5T (45 directions, b=1000 s/mm(2)). Regions of interest were defined on a study-specific fractional anisotropy template and mapped onto subjects for fiber tracking. Probabilistic fiber tracking of the corticospinal tract and thalamic projections to the somatosensory cortex was performed by using constrained spherical deconvolution. Tracts were qualitatively assessed, and DTI parameters were extracted close to and distant from lesions and compared between groups.RESULTS: The corticospinal tract and thalamic projections to the somatosensory cortex were realistically reconstructed in both groups. Structural changes to tracts were seen in the cerebral palsy group and included splits, dislocations, compaction of the tracts, or failure to delineate the tract and were associated with underlying pathology seen on conventional MR imaging. Comparisons of DTI parameters indicated primary and secondary neurodegeneration along the corticospinal tract. Corticospinal tract and thalamic projections to the somatosensory cortex showed dissimilarities in both structural changes and DTI parameters.CONCLUSIONS: Our proposed method offers a sensitive means to explore alterations in WM tracts to further understand pathophysiologic changes following early acquired brain injury.
|
|
| 9. |
- Lennartsson, Finn, et al.
(författare)
-
Developing a framework for studying brain networks in neonatal hypoxic-ischemic encephalopathy
- 2018
-
Ingår i: Medical Image Understanding and Analysis - 22nd Conference, Proceedings. - Cham : Springer International Publishing. - 1865-0929. - 9783319959207 ; 894, s. 203-216
-
Konferensbidrag (refereegranskat)abstract
- Newborns with hypoxic-ischemic encephalopathy (HIE) are at high risk of brain injury, with subsequent developmental problems including severe neuromotor, cognitive and behavioral impairment. Neural correlates of cognitive and behavioral impairment in neonatal HIE, in particular in infants who survive without severe neuromotor impairment, are poorly understood. It is reasonable to hypothesize that in HIE both structural and functional brain networks are altered, and that this might be the neural correlate of impaired cognitive and/or behavioral impairment in HIE. Here, an analysis pipeline to study the structural and functional brain networks from neonatal MRI in newborns with HIE is presented. The structural connectivity is generated from dense whole-brain tractograms derived from diffusion-weighted MR fibre tractography. This investigation of functional connectivity focuses on the emerging resting state networks (RSNs), which are sensitive to injuries from hypoxic-ischemic insults to the newborn brain. In conjunction with the structural connectivity, alterations to the structuro-functional connectivity of the RSNs can be studied. Preliminary results from a proof-of-concept study in a small cohort of newborns with HIE are promising. The obstacles encountered and improvements to the pipeline are discussed. The framework can be further extended for joint analysis with EEG functional-connectivity.
|
|
| 10. |
- Lennartsson, Finn
(författare)
-
Diffusion magnetic resonance imaging for investigating alterations in brain organization after injury during early development : with specific reference to the motor and visual system
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Disturbances or injuries to the brain during early development cause different types of structural abnormalities, depending mainly on the stage of maturation of the brain at the time of the insult. These are, herein, collectively referred to as early brain lesions. Early brain lesions can cause a wide range of clinical symptoms including disturbances to motor or sensory functions, perception, cognition, communication and behaviour; epilepsy is common. There is a large variation in outcomes and severity of impairments, contributed to by the superior compensatory mechanisms in the young brain compared to the adult brain. The overall aim of this thesis was to study the organization of the motor and visual system in early brain lesions by using diffusion-weighted magnetic resonance imaging (MRI) and white matter fibre tractography. The specific aims of the studies on the motor system (Study I & II) were to investigate the microstructural changes in motor and sensory tracts in individuals with early brain lesions causing unilateral cerebral palsy (CP), and to explore associations with hand motor function. The specific aims of the studies on the visual system (Study III & IV) were to seek evidence of a relationship between damage to the immature optic radiation (OR) and subsequent development of the retinal ganglion cell layers, and associated visual field function, in individuals with early brain lesions caused by with white matter damage of immaturity (WMDI). The results from Study I showed that diffusion parameters in central cortico-fugal fibres, distant from the primary lesions, were sensitive markers for injury and correlated with hand function in the non‐dominant hand in children with unilateral CP. Study II used an improved fibre tractography method in the same cohort, to study the cortico-spinal tract (CST) and adjacent thalamic projections to the primary sensory cortex (TRS1). The results showed dissimilarities in both the structural and the parametric changes seen in CST compared to TRS1 on the lesion-side, indicating that the tracts are affected differently by the injury; however, reactive changes in TRS1 is a possible alternative explanation. The results from Study III show that injuries to the immature OR are associated with reduced thickness of the retinal nerve fibre layer, causing predictable visual field defects. Study IV showed, by including visual field mapping with functional MRI, a strict topographical and correlating relationship between injury to the superior portion of the OR, the part of OR that projected to the visual field map below the horizontal meridian, and the secondary thinning of the macular ganglion cell layer, and corresponding visual field defects. The results from both studies provide convincing evidence of retrograde trans-synaptic degeneration in WMDI. The structural changes to the OR may suggest re-organisation to the tract upon injury. The overall conclusion from this thesis is that diffusion-weighted MRI is more sensitive in detecting and assessing the extent of early brain lesions than conventional MRI, and provides a sensitive marker for studying relevant changes to structural entities of fibre tracts that have a direct effect on the clinical function.
|
|
| 11. |
|
|
| 12. |
- Lennartsson, Finn, et al.
(författare)
-
Pre- and Postnatal Damage to the Retro-Geniculate Visual Pathways Cause Retinal Degeneration Predictive for Visual Function
- 2021
-
Ingår i: Frontiers in Human Neuroscience. - : Frontiers Media SA. - 1662-5161. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- To increase the understanding of the relationship between structure and function in individuals with damage to the brain from different stages of maturation of the visual system, we examined 16 teenagers and young adults. We used diffusion-weighted magnetic resonance imaging (MRI) and fiber tractography of the optic radiation (OR) and optical coherence tomography (OCT) of the peripapillary retinal nerve fiber layer (pRNFL) and the ganglion cell layer + inner plexiform layer (GC+IPL) in the macula. Visual field (VF) function was assessed with the Humphrey Field Analyzer (HFA). Injuries to the immature OR were associated with thinning of the pRNFL and GC+IPL, and corresponding VF defects irrespectively of timing of the lesion. However, in cases with bilateral white-matter damage of immaturity (WMDI) we noticed a well preserved central VF despite a very thin GC+IPL. We speculate that this is due to plasticity in the immature visual system. Similar results were not noticed among cases with unilateral damage, acquired pre- or postnatally, in which the central VF was affected in most cases. OCT has proved to be a valuable targeted tool in children with damage to the retro-geniculate visual pathways, and that focal thinning of the GC+IPL predicts VF defects. This brief research report includes a review of four previously published papers. In addition, we present one new case and apply a recently developed classification system for CVI. The classification was applied on cases with bilateral WMDI to investigate its relation to retinal structure.
|
|
| 13. |
- Nilsson, Maria, et al.
(författare)
-
Case report : Bilateral damage to the immature optic radiation and secondary massive loss of retinal ganglion cells causing tunnel vision
- 2023
-
Ingår i: Frontiers in Neuroscience. - 1662-4548. ; 17
-
Tidskriftsartikel (refereegranskat)abstract
- We describe the case of a 30-year-old woman, who needed a formal report on her visual impairment to seek support from society. She was born preterm, and during her neonatal period, she suffered from bilateral intraventricular hemorrhage (IVH) grade 3, a condition that can cause cerebral visual impairment (CVI) due to damage to the retro-geniculate visual pathways. Individuals with such brain damage of this severity are often restricted by cerebral palsy (CP) and intellectual disability, and thus have a limited ability to cooperate in the assessment of visual function. However, our patient was capable of providing reliable test results, and she manifested only a small island of central vision in each eye, with additional reduced visual acuities. She cooperated well in examinations involving MRI of the brain, optical coherence tomography (OCT) of retinal ganglion cells, and multi-focal visual evoked potentials, with each test providing information about potential limitations in the structural prerequisites for visual function. What distinguishes our case is the severity of the damage to the optic radiations and the massive secondary loss of most of her retinal ganglion cells (GCs). However, there is some measurable visual function, which may be due to developmental neuroplasticity during early development, when surviving GCs prioritize the central visual field. Despite her visual difficulties, she is a keen portrait painter. Our patient may be representative of, and a spokesperson for, other individuals with extensive brain damage of the same etiology, who are unable to perform perimetric tests and therefore run the risk of not being recognized as severely visually impaired, and consequently, not being given the best conditions for habilitation. OCT may serve as a helpful diagnostic tool. Aim: This study aims to describe visual behavior and practical applications of visual function in relation to structural prerequisites for visual function.
|
|
| 14. |
- Padilla, Nelly, et al.
(författare)
-
Breakdown of Whole-brain Dynamics in Preterm-born Children
- 2020
-
Ingår i: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 30:3, s. 1159-1170
-
Tidskriftsartikel (refereegranskat)abstract
- The brain operates at a critical point that is balanced between order and disorder. Even during rest, unstable periods of random behavior are interspersed with stable periods of balanced activity patterns that support optimal information processing. Being born preterm may cause deviations from this normal pattern of development. We compared 33 extremely preterm (EPT) children born at < 27 weeks of gestation and 28 full-term controls. Two approaches were adopted in both groups, when they were 10 years of age, using structural and functional brain magnetic resonance imaging data. The first was using a novel intrinsic ignition analysis to study the ability of the areas of the brain to propagate neural activity. The second was a whole-brain Hopf model, to define the level of stability, desynchronization, or criticality of the brain. EPT-born children exhibited fewer intrinsic ignition events than controls; nodes were related to less sophisticated aspects of cognitive control, and there was a different hierarchy pattern in the propagation of information and suboptimal synchronicity and criticality. The largest differences were found in brain nodes belonging to the rich-club architecture. These results provide important insights into the neural substrates underlying brain reorganization and neurodevelopmental impairments related to prematurity.
|
|
| 15. |
- Truong, My, et al.
(författare)
-
Classifications of atherosclerotic plaque components with T1 and T2* mapping in 11.7 T MRI
- 2021
-
Ingår i: European Journal of Radiology Open. - : Elsevier BV. - 2352-0477. ; 8, s. 100323-100323
-
Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Histopathology is the gold standard for analysis of atherosclerotic plaques but has drawbacks due to the destructive nature of the method. Ex vivo MRI is a non-destructive method to image whole plaques. Our aim was to use quantitative high field ex vivo MRI to classify plaque components, with histology as gold standard.Methods: Surgically resected carotid plaques from 12 patients with recent TIA or stroke were imaged at 11.7 T MRI. Quantitative T1/T2* mapping sequences and qualitative T1/T2* gradient echo sequences with voxel size of 30 × 30 × 60 μm3 were obtained prior to histological preparation, sectioning and staining for lipids, inflammation, hemorrhage, and fibrous tissue. Regions of interest (ROI) were selected based on the histological staining at multiple levels matched between histology and MRI. The MRI parameters of each ROI were then analyzed with quadratic discriminant analysis (QDA) for classification.Results: A total of 965 ROIs, at 70 levels matched between histology and MRI, were registered based on histological staining. In the nine plaques where three or more plaque components were possible to co-localize with MRI, the mean degree of misclassification by QDA was 16.5 %. One of the plaques contained mostly fibrous tissue and lipids and had no misclassifications, and two plaques mostly contained fibrous tissue. QDA generally showed good classification for fibrous tissue and lipids, whereas plaques with hemorrhage and inflammation had more misclassifications.Conclusion: 11.7 T ex vivo high field MRI shows good visual agreement with histology in carotid plaques. T1/T2* maps analyzed with QDA is a promising non-destructive method to classify plaque components, but with a higher degree of misclassifications in plaques with hemorrhage or inflammation.
|
|
