| 1. |
- Lundberg, Peter, et al.
(författare)
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Kvantifiering av leversteatos: diagnostisk utvärdering av protonmagnetresonansspektroskopi jämfört med histologiska metoder
- 2016
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Konferensbidrag (refereegranskat)abstract
- BakgrundLeversteatos är den vanligaste manifestationen av leversjukdom i västvärlden. Leverbiopsi med semikvantitativ histologisk gradering är referensmetod vid gradering av leversteatos. Med protonmagnetsresonansspektroskopi (1H-MRS), en metod som föreslagits ersätta leverbiopsi för värdering av steatos, kan leverns innehåll av triglycerider mätas icke-invasivt. Triglyceridinnehåll >5,00 % används ofta som ett diagnostiskt kriterium för leversteatos vid undersökning med 1H-MRS. Syftet med studien var att jämföra 1H-MRS med semikvantitativ histologisk steatosgradering och kvantitativ histologisk steatosmätning.MetodPatienter remitterade för utredning av förhöjda leverenzymer in-kluderades i studien. Samtliga patienter genomgick klinisk undersökning, laboratorieprovtagning samt 1H-MRS direkt följd av leverbiopsi. För konventionell histologisk semikvantitativ gradering av steatos användes kriterierna utarbetade av Brunt och medarbetare. Kvantitativ mätning av fett i biopsierna utfördes genom att med hjälp av stereologisk punkträkning (SPC) mäta andelen av ytan som innehöll fettvakuoler.ResultatI studien inkluderades 94 patienter, varav 37 hade icke-alkoholor-sakad fettleversjukdom (NAFLD), 49 hade andra leversjukdomar och 8 hade normal leverbiopsi. En stark korrelation noterades mel-lan 1H-MRS och SPC (r=0,92, p<0,0001; к=0.82). Korrelationen mellan 1H-MRS och Brunts kriterier (к=0.26) samt mellan SPC och Brunts kriterier (к=0.38) var betydligt sämre. När patologens gradering (Brunts kriterier) användes som referensmetod för diag-nos av leversteatos så hade alla patienter med triglyceridinnehåll >5,00 % mätt med 1H-MRS steatos (specificitet 100 %). Emellertid hade 22 av 69 patienter med triglyceridinnehåll ≤5,00 % också le-versteatos enligt Brunts kriterier (sensitivitet 53 %). Motsvarande siffror när man använde gränsvärdet 3,02 % var sensitivitet 79 % och specificitet 100 %. Vid ytterligare reduktion av gränsvärdet för triglyceridinnehåll till 2,00 % ökade sensitiviteten till 87 % med upprätthållande av hög specificitet (94 %).Slutsats1H-MRS och SPC uppvisade en mycket hög korrelation vid kvantifiering av leversteatos. SPC borde därför föredras framför Brunts kriterier när noggrann histologisk kvantifiering av leversteatos är önskvärd. Många patienter kan ha histologisk leversteatos trots triglyceridinnehåll ≤5,00 % mätt med 1H-MRS. Gränsvärdet för diagnostisering av leversteatos med 1H-MRS bör därför reduceras.
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| 2. |
- Engström, Gunnar, et al.
(författare)
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The Swedish CArdioPulmonary BioImage Study : objectives and design
- 2015
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 278:6, s. 645-659
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Tidskriftsartikel (refereegranskat)abstract
- Cardiopulmonary diseases are major causes of death worldwide, but currently recommended strategies for diagnosis and prevention may be outdated because of recent changes in risk factor patterns. The Swedish CArdioPulmonarybioImage Study (SCAPIS) combines the use of new imaging technologies, advances in large-scale 'omics' and epidemiological analyses to extensively characterize a Swedish cohort of 30 000 men and women aged between 50 and 64 years. The information obtained will be used to improve risk prediction of cardiopulmonary diseases and optimize the ability to study disease mechanisms. A comprehensive pilot study in 1111 individuals, which was completed in 2012, demonstrated the feasibility and financial and ethical consequences of SCAPIS. Recruitment to the national, multicentre study has recently started.
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| 3. |
- van Westen, Danielle, et al.
(författare)
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Cerebral white matter lesions - associations with A beta isoforms and amyloid PET
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6:20709
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Tidskriftsartikel (refereegranskat)abstract
- Small vessel disease (SVD) and amyloid deposition may promote each other, with a potential association between SVD and altered production or clearance of beta-amyloid (A beta) affecting its cleavage products. We investigated the relationship between SVD, multiple isoforms of A beta in cerebrospinal fluid (CSF) and cortical A beta in 831 subjects with cognitive performance ranging from normal to Alzheimer's disease (AD) (the Swedish BioFINDER study). SVD was estimated as white matter lesions (WML) and lacunes. 18F-flutemetamol PET was performed in 321 subjects. Lower CSF levels of A beta 38 and A beta 40 were consistently associated with increased WML in all subgroups, while lower levels of CSF A beta 42 were associated with WML mainly in AD. CSF A beta 38 and A beta 40 were associated with regional WML in all regions, while CSF A beta 42 was associated with temporal WML only. A composite measure of 18F-flutemetamol uptake was not associated with WML, and regional 18F-flutemetamol uptake only with temporal WML. Lacunes were not associated with A beta isoforms nor 18F-flutemetamol uptake. Our results suggest that WML may be associated with alterations in the production or clearance of A beta species, particularly of A beta 38 and A beta 40. However, in AD cases, A beta 42 pathology might be associated with WML, especially in the temporal lobe.
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| 4. |
- Hadimeri, Ursula
(författare)
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Factors affecting the physical characteristics of arterio-venous fistula in patients with renal failure
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background and PurposeA patent access is vital for a dialysis patient. The arterio-venous fistula (AVF), the most important access for haemodialysis (HD), is frequently affected by extensive complications such as stenosis and occlusions.Study I: To investigate whether the dimensions of AVFs used for performing haemodialysis were affected by the original disease.Study II: To investigate if the diameter of the distal radiocephalic fistula could influence left ventricular variables in stable haemodialysis patients.Study III: To investigate whether a single Far Infrared (FIR) light treatment could alter blood velocity, AVF diameter or inflammatory markers.Study IV: To evaluate in what extent the renal diagnosis and radiological interventions affected the dysfunction of AVF and results of percutaneous transluminal angioplasty (PTA).Materials and methodsStudy I: The lumen diameter of the AVF was studied by ultrasound in 19 patients with autosomal dominant polycystic kidney disease (ADPKD) and in 19 control patients. The monitoring was performed along the forearm part of the vein, the maximal diameter was measured. The diameters of the two needle insertion sites were also measured.Study II: Nineteen patients were investigated with echocardiography, using M-mode recordings and measurements in the 2D image. Ultrasound and doppler ultrasound were performed. Transsonic measurements were performed after the ultrasound investigation. Measurements of the diameter of the AVF were performed in four locations. Heart variables were analysed regarding left ventricular (LV) criteria.Study III: Thirty patients with native AVF in the forearm were included. Each patient was his/her own control. Ultrasound examinations of the AVF diameter and blood flow velocity were performed before and after a single Far Infrared light (FIR) treatment.Study IV: 522 radiological investigations and endovascular treatments between January 1, 2006 and December 31, 2014 were analysed in 174 patients, retrospectively. All investigations had been performed due to clinical suspicion of impaired AVF function. All stenoses were evaluated and the number, degree, length, location and relation to anastomosis were recorded. After PTA the remaining stenoses were evaluated again and complications were recorded.ResultsStudy I: The diameter of the AVF at the maximal site in patients with ADPKD was significantly wider than that for the control patients.Study II: A larger AVF mean and maximal diameter worsened left ventricular characteristics.Study III: A single FIR treatment resulted in a significant increase in blood velocity over the AV fistula from a mean of 2.1±1.0 m/s to 2.3±1.0 m/s. The diameter of the arterialized vein became wider, i.e. 0.72±0.02 to 0.80±0.02 cm. The increase in fistula blood velocity correlated positively with baseline serum-urate and the increase in venous diameter correlated positively with the baseline plasma orosomucoid concentration.Study IV: The degree of AVF stenosis before PTA correlated significantly with the degree of remaining stenosis after intervention. Arterial stenosis was significantly more frequent among patients with diabetic nephropathy and interstitial nephritis. A shorter life span between PTAs was related to diabetic nephropathy.ConclusionsStudy I: The receiving veins of AVF in patients with ADPKD have an abnormality that causes a greater than normal dilatation in response to the arterialization.Study II: The maximal diameter of the distal AVF seems to be a sensitive marker of LV impairment in stable haemodialysis patients.Study III: A single FIR treatment increased AVF blood velocity and vein diameter. Thus, one FIR treatment can help maturation of AVF in the early postoperative course.Study IV: Repeated PTA was performed significantly more often in patients with diabetic nephropathy. Clinically significant stenosis should be dilated as soon as possible. Occlusion of the AVF should be thrombolyzed and/or dilated when diagnosed.
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| 5. |
- Johansson, Björn
(författare)
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Opacification of anterior part of hydrophilic acrylic IOL or a prelenticular inflammatory membrane?
- 2012
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Ingår i: Journal of cataract and refractive surgery. - Philadelphia : Elsevier. - 0886-3350 .- 1873-4502. ; 38:6, s. 1115-1116
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Tidskriftsartikel (refereegranskat)abstract
- In their recent case report, Park and Chuck1 describe the bilateral appearance of an opacification at the plane of the anterior surface of the hydrophilic acrylic Akreos MI60 intraocular lens (IOL) (Bausch & Lomb). The patient's general history of diabetes mellitus, proliferative retinopathy, and iris rubeosis explains the limited pupil dilation preventing visualization of the capsulorhexis opening in their slitlamp images.
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| 6. |
- Karlsson, Markus, et al.
(författare)
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Increased bile excretion of Gd-EOB-DTPA in diffuse liver disease : mechanistic modeling of qDCE-MRI in patients with severe fibro-sis
- 2016
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Ingår i: Magnetic Resonance Materials in Physics, Biology and Medicine. - : Springer. - 0968-5243 .- 1352-8661. ; 29:1, s. S272-S273
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionOver the past decades, several different non-invasive methods for staging hepatic fibrosis have been proposed. One such method is dynamic contrast enhanced MRI (DCE-MRI) using the contrast agent (CA) Gd-EOB-DTPA. Gd-EOB-DTPA is liver specific, which means that it is taken up specifically by the hepatocytes via the OATP3B1/B3 transporters and excreted into the bile via the MRP2 transporter. Several studies have shown that DCE-MRI and Gd-EOBDTPA can separate patients with advanced (F3-F4) from mild (F0-F2) hepatic fibrosis by measuring the signal intensity, where patients with advanced fibrosis have a lower signal intensity than the mild fibrosis cases.1 However, none of the studies up to date have been able to differentiate if the reduced signal intensity in the liver is because of an decreased uptake of CA or an increased excretion. Analyzing the DCE-MRI data with mechanistic mathematical modelling has the possibility of investigating such a differentiation.Subjects and methods88 patients with diffuse liver disease were examined using DCE-MRI (1.5 T Philips Achieva, two-point Dixon, TR=6.5 ms, TE=2.3/4.6 ms, FA=13) after a bolus injection of Gd-EOB-DTPA, followed by a liver biopsy. Regions of interest were placed within the liver, spleen and veins and a whole-body mechanistic pharmacokinetic model2 was fitted to the data. The fitted parameters in the model correspond to the rate of CA transport between different compartments, e.g. hepatocytes, blood plasma, and bile (Fig. 1).ResultsAs can be seen in Fig. 2, the parameter corresponding to the transport of CA from the blood plasma to the hepatocytes, kph, is lower for patients with advanced fibrosis (p=0.01). Fig. 3 shows that the parameter corresponding to the CA excretion into the bile, khb, is higher for patients with advanced fibrosis (p<0.01).Discussion/ConclusionThis work shows that the decreased signal intensity in DCE-MRI images in patients with advanced fibrosis depends on both a decreased uptake of CA in the hepatocytes and an increased excretion into the bile. Similar results have also been observed in a rat study3. In that study, rats with induced cirrhosis had a higher MRP2-activity than the healthy control rats.References1Norén et al: Eur. Radiol, 23(1), 174-181, 2013.2Forsgren et al: PloS One, 9(4): e95700, 2014.3Tsuda & Matsui: Radiol, 256(3): 767-773, 2010.
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| 7. |
- Ahlander, Britt-Marie, 1954-, et al.
(författare)
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An echo-planar imaging sequence is superior to a steady-state free precession sequence for visual as well as quantitative assessment of cardiac magnetic resonance stress perfusion
- 2017
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Ingår i: Clinical Physiology and Functional Imaging. - : Blackwell Publishing. - 1475-0961 .- 1475-097X. ; 37:1, s. 52-61
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To assess myocardial perfusion, steady-state free precession cardiac magnetic resonance (SSFP, CMR) was compared with gradient-echo-echo-planar imaging (GRE-EPI) using myocardial perfusion scintigraphy (MPS) as reference.METHODS: Cardiac magnetic resonance perfusion was recorded in 30 patients with SSFP and in another 30 patients with GRE-EPI. Timing and extent of inflow delay to the myocardium was visually assessed. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated. Myocardial scar was visualized with a phase-sensitive inversion recovery sequence (PSIR). All scar positive segments were considered pathologic. In MPS, stress and rest images were used as in clinical reporting. The CMR contrast wash-in slope was calculated and compared with the stress score from the MPS examination. CMR scar, CMR perfusion and MPS were assessed separately by one expert for each method who was blinded to other aspects of the study.RESULTS: Visual assessment of CMR had a sensitivity for the detection of an abnormal MPS at 78% (SSFP) versus 91% (GRE-EPI) and a specificity of 58% (SSFP) versus 84% (GRE-EPI). Kappa statistics for SSFP and MPS was 0·29, for GRE-EPI and MPS 0·72. The ANOVA of CMR perfusion slopes for all segments versus MPS score (four levels based on MPS) had correlation r = 0·64 (SSFP) and r = 0·96 (GRE-EPI). SNR was for normal segments 35·63 ± 11·80 (SSFP) and 17·98 ± 8·31 (GRE-EPI), while CNR was 28·79 ± 10·43 (SSFP) and 13·06 ± 7·61 (GRE-EPI).CONCLUSION: GRE-EPI displayed higher agreement with the MPS results than SSFP despite significantly lower signal intensity, SNR and CNR.
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| 8. |
- Blystad, Ida, et al.
(författare)
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Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent
- 2016
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Ingår i: American Journal of Neuroradiology. - : American Society of Neuroradiology (ASNR). - 0195-6108 .- 1936-959X. ; 37:1, s. 94-100
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Contrast-enhancing MS lesions are important markers of active inflammation in the diagnostic work-up of MS and in disease monitoring with MR imaging. Because intravenous contrast agents involve an expense and a potential risk of adverse events, it would be desirable to identify active lesions without using a contrast agent. The purpose of this study was to evaluate whether pre-contrast injection tissue-relaxation rates and proton density of MS lesions, by using a new quantitative MR imaging sequence, can identify active lesions.MATERIALS AND METHODS: Forty-four patients with a clinical suspicion of MS were studied. MR imaging with a standard clinical MS protocol and a quantitative MR imaging sequence was performed at inclusion (baseline) and after 1 year. ROIs were placed in MS lesions, classified as nonenhancing or enhancing. Longitudinal and transverse relaxation rates, as well as proton density were obtained from the quantitative MR imaging sequence. Statistical analyses of ROI values were performed by using a mixed linear model, logistic regression, and receiver operating characteristic analysis.RESULTS: Enhancing lesions had a significantly (P < .001) higher mean longitudinal relaxation rate (1.22 ± 0.36 versus 0.89 ± 0.24), a higher mean transverse relaxation rate (9.8 ± 2.6 versus 7.4 ± 1.9), and a lower mean proton density (77 ± 11.2 versus 90 ± 8.4) than nonenhancing lesions. An area under the receiver operating characteristic curve value of 0.832 was obtained.CONCLUSIONS: Contrast-enhancing MS lesions often have proton density and relaxation times that differ from those in nonenhancing lesions, with lower proton density and shorter relaxation times in enhancing lesions compared with nonenhancing lesions.
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| 9. |
- Tydén, Jonas, et al.
(författare)
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Increased Plasma Levels of Heparin-Binding Protein on Admission to Intensive Care Are Associated with Respiratory and Circulatory Failure
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Heparin-binding protein (HBP) is released by granulocytes and has been shown to increase vascular permeability in experimental investigations. Increased vascular permeability in the lungs can lead to fluid accumulation in alveoli and respiratory failure. A generalized increase in vascular permeability leads to loss of circulating blood volume and circulatory failure. We hypothesized that plasma concentrations of HBP on admission to the intensive care unit (ICU) would be associated with decreased oxygenation or circulatory failure.Methods: This is a prospective, observational study in a mixed 8-bed ICU. We investigated concentrations of HBP in plasma at admission to the ICU from 278 patients. Simplified acute physiology score (SAPS) 3 was recorded on admission. Sequential organ failure assessment (SOFA) scores were recorded daily for three days.Results: Median SAPS 3 was 58.8 (48-70) and 30-day mortality 64/278 (23%). There was an association between high plasma concentrations of HBP on admission with decreased oxygenation (p<0.001) as well as with circulatory failure (p<0.001), after 48-72 hours in the ICU. There was an association between concentrations of HBP on admission and 30-day mortality (p = 0.002). ROC curves showed areas under the curve of 0,62 for decreased oxygenation, 0,65 for circulatory failure and 0,64 for mortality.Conclusions: A high concentration of HBP in plasma on admission to the ICU is associated with respiratory and circulatory failure later during the ICU care period. It is also associated with increased 30-day mortality. Despite being an interesting biomarker for the composite ICU population it's predictive value at the individual patient level is low.
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| 10. |
- Virhammar, Johan, et al.
(författare)
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Quantitative MRI for Rapid and User-Independent Monitoring of Intracranial CSF Volume in Hydrocephalus
- 2016
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Ingår i: American Journal of Neuroradiology. - : AMER SOC NEURORADIOLOGY. - 0195-6108 .- 1936-959X. ; 37:5, s. 797-801
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Quantitative MR imaging allows segmentation of different tissue types and automatic calculation of intracranial volume, CSF volume, and brain parenchymal fraction. Brain parenchymal fraction is calculated as (intracranial volume - CSF volume) / intracranial volume. The purpose of this study was to evaluate whether the automatic calculation of intracranial CSF volume or brain parenchymal fraction could be used as an objective method to monitor volume changes in the ventricles.MATERIALS AND METHODS: A lumbar puncture with drainage of 40 mL of CSF was performed in 23 patients under evaluation for idiopathic normal pressure hydrocephalus. Quantitative MR imaging was performed twice within 1 hour before the lumbar puncture and was repeated 30 minutes, 4 hours, and 24 hours afterward. For each time point, the volume of the lateral ventricles was manually segmented and total intracranial CSF volume and brain parenchymal fraction were automatically calculated by using Synthetic MR postprocessing.RESULTS: At 30 minutes after the lumbar puncture, the volume of the lateral ventricles decreased by 5.6 ± 1.9 mL (P < .0001) and the total intracranial CSF volume decreased by 11.3 ± 5.6 mL (P < .001), while brain parenchymal fraction increased by 0.78% ± 0.41% (P < .001). Differences were significant for manual segmentation and brain parenchymal fraction even at 4 hours and 24 hours after the lumbar tap. There was a significant association using a linear mixed model between change in manually segmented ventricular volume and change in brain parenchymal fraction and total CSF volume, (P < .0001).CONCLUSIONS: Brain parenchymal fraction is provided rapidly and fully automatically with Synthetic MRI and can be used to monitor ventricular volume changes. The method may be useful for objective clinical monitoring of hydrocephalus.
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