| 1. |
- Alamidi, Daniel, et al.
(författare)
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T1 Relaxation Time in Lungs of Asymptomatic Smokers.
- 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
- Interest in using T1 as a potential MRI biomarker of chronic obstructive pulmonary disease (COPD) has recently increased. Since tobacco smoking is the major risk factor for development of COPD, the aim for this study was to examine whether tobacco smoking, pack-years (PY), influenced T1 of the lung parenchyma in asymptomatic current smokers.
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| 2. |
- Alamidi, Daniel, et al.
(författare)
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COPD Patients Have Short Lung Magnetic Resonance T1 Relaxation Time.
- 2016
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Ingår i: COPD. - : Informa UK Limited. - 1541-2563 .- 1541-2555. ; 13:2, s. 153-159
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic resonance imaging (MRI) may provide attractive biomarkers for assessment of pulmonary disease in clinical trials as it is free from ionizing radiation, minimally invasive and allows regional information. The aim of this study was to characterize lung MRI T1 relaxation time as a biomarker of chronic obstructive pulmonary disease (COPD); and specifically its relationship to smoking history, computed tomography (CT), and pulmonary function test (PFT) measurements in comparison to healthy age-matched controls. Lung T1 and inter-quartile range (IQR) of T1 maps from 24 COPD subjects and 12 healthy age-matched non-smokers were retrospectively analyzed from an institutional review board approved study. The subjects underwent PFTs and two separate MR imaging sessions at 1.5 tesla to test T1 repeatability. CT scans were performed on the COPD subjects. T1 repeatability (intraclass correlation coefficient) was 0.72 for repeated scans acquired on two visits. The lung T1 was significantly shorter (p < 0.0001) and T1 IQR was significantly larger (p = 0.0002) for the COPD subjects compared to healthy controls. Lung T1 significantly (p = 0.001) correlated with lung density assessed with CT. Strong significant correlations (p < 0.0001) between lung T1 and all PFT measurements were observed. Cigarette exposure did not correlate with lung T1 in COPD subjects. In conclusion, lung MRI T1 mapping shows potential as a repeatable, radiation free, non-invasive imaging technique in the evaluation of COPD.
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| 3. |
- Alamidi, Daniel, et al.
(författare)
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Variable Flip Angle 3D Ultrashort Echo Time (UTE) T-1 Mapping of Mouse Lung: A Repeatability Assessment
- 2018
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807 .- 1522-2586. ; 48:3, s. 846-852
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Tidskriftsartikel (refereegranskat)abstract
- Background: Lung T-1 is a potential translational biomarker of lung disease. The precision and repeatability of variable flip angle (VFA) T-1 mapping using modern 3D ultrashort echo time (UTE) imaging of the whole lung needs to be established before it can be used to assess response to disease and therapy. Purpose: To evaluate the feasibility of regional lung T-1 quantification with VFA 3D-UTE and to investigate long-and short-term T-1 repeatability in the lungs of naive mice. Field strength/Sequence: 3D free-breathing radial UTE (8 mu s) at 4.7T. Assessment: VFA 3D-UTE T-1 calculations were validated against T-1 values measured with inversion recovery (IR) in phantoms. Lung T-1 and proton density (S-0) measurements of whole lung and muscle were repeated five times over 1 month in free-breathing naive mice. Two consecutive T-1 measurements were performed during one of the imaging sessions. Statistical Tests: Agreement in T-1 between VFA 3D-UTE and IR in phantoms was assessed using Bland-Altman and Pearson's correlation analysis. The T-1 repeatability in mice was evaluated using coefficient of variation (CV), repeated-measures analysis of variance (ANOVA), and paired t-test. Results: Good T-1 agreement between the VFA 3D-UTE and IR methods was found in phantoms. T-1 in lung and muscle showed a 5% and 3% CV (1255 +/- 63 msec and 1432 +/- 42 msec, respectively, mean +/- SD) with no changes in T-1 or S-0 over a month. Consecutive measurements resulted in an increase of 2% in both lung T-1 and S-0. Data Conclusion: VFA 3D-UTE shows promise as a reliable T-1 mapping method that enables full lung coverage, high signal-to-noise ratio (similar to 25), and spatial resolution (300 mu m) in freely breathing animals. The precision of the VFA 3D-UTE method will enable better design and powering of studies.
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| 4. |
- Bech-Hanssen, Odd, 1956, et al.
(författare)
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Left ventricular volumes by echocardiography in chronic aortic and mitral regurgitation.
- 2016
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Ingår i: Scandinavian cardiovascular journal : SCJ. - : Informa UK Limited. - 1651-2006 .- 1401-7431. ; 50:3, s. 154-161
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Tidskriftsartikel (refereegranskat)abstract
- Cut-off values for left ventricular (LV) dimensions indicating severe valve regurgitation have not been defined. The aim of the study was to establish echocardiographic cut-off values for LV dimensions indicating severe chronic aortic (AR) or mitral (MR) regurgitation.
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| 5. |
- Hebelka, Hanna, 1977, et al.
(författare)
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The importance of level stratification for quantitative MR studies of lumbar intervertebral discs: a cross-sectional analysis in 101 healthy adults
- 2019
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Ingår i: European Spine Journal. - : Springer Science and Business Media LLC. - 0940-6719 .- 1432-0932. ; 28:9, s. 2153-2161
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate whether quantitative T2-times depend on lumbar intervertebral disc (IVD) level. Methods: The lumbar spine (Th12/L1–L5/S1) of 101 participants (53.5% female, 30.0[± 3.6]years, 173.5[± 9.6]cm and 69.9[± 13.4]kg), without history of back pain, was examined on a 3T scanner with sagittal T2-mapping. All IVDs were stratified according to Pfirrmann grade and lumbar level, with mean T2-time determined for the entire IVD volume and in five subregions of interests. Results: Significant level-dependent T2-time differences were detected, both for the entire IVD volume and its subregions. For the entire IVD volume, Pfirrmann grade 2 IVDs displayed 9–18% higher T2-times in Th12/L1 IVDs compared to L2/L3–L5/S1 IVDs (0.001 > p < 0.004) and significantly different T2-times in L1/L2–L2/L3 IVDs compared to most of the IVDs in the lower lumbar spine. In Pfirrmann grades 1, 3 and 4 IVDs, no significant level-dependent T2-time differences were observed for the entire IVD. More pronounced results were observed when comparing IVD subregions, with significant level-dependent differences also within Pfirrmann grade 1 and grade 3 IVDs. For example, in posterior IVD subregions mean T2-time was 80–82% higher in Th12/L1 compared to L3/L4–L4/L5 Pfirrmann grade 1 IVDs (p < 0.05) and 10–14% higher in L5/S1 compared to L3/L4–L4/L5 Pfirrmann grade 3 IVDs (0.02 > p < 0.001). Discussion: Significant level-dependent T2-time differences within several Pfirrmann grades, both for the entire IVD volume and for multiple IVD subregions, were shown in this large cohort study. The T2-time differences between levels existed in both non-degenerated and degenerated IVDs. These findings show the importance of stratifying for lumbar level when quantitative IVD studies are performed using T2-mapping. Graphic abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.]. © 2019, The Author(s).
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| 6. |
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| 7. |
- Bech-Hanssen, Odd, 1956, et al.
(författare)
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Characterization of complex flow patterns in the ascending aorta in patients with aortic regurgitation using conventional phase-contrast velocity MRI.
- 2018
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Ingår i: The international journal of cardiovascular imaging. - : Springer Science and Business Media LLC. - 1875-8312 .- 1569-5794 .- 1573-0743. ; 34:3, s. 419-429
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Tidskriftsartikel (refereegranskat)abstract
- Ascending aorta (AA) flow displacement (FD) is a surrogate for increased wall shear stress. We prospectively studied the flow profile in the AA in patients with aortic regurgitation (AR), to identify predictors of FD and investigate whether magnetic resonance imaging (MRI) phase-contrast flow rate curves (PC-FRC) contain quantitative information related to FD. Forty patients with chronic moderate (n=14) or severe (n=26) AR (21 (53%) with bicuspid aortic valve) and 22 controls were investigated. FD was determined from phase-contrast velocity profiles and defined as the distance between the center of the lumen and the "center of velocity" of the peak systolic forward flow or the peak diastolic negative flow, normalized to the lumen radius. Forward and backward volume flow was determined separately for systole and diastole. Seventy percent had systolic backward flow and 45% had diastolic forward flow in large areas of the vessel. AA dimension was an independent predictor of systolic FD while AA dimension and regurgitant volume were independent predictors of diastolic FD. Valve phenotype was not an independent predictor of systolic or diastolic FD. The linear relationships between systolic backward flow and systolic FD and diastolic forward flow and diastolic FD were strong (R=0.77 and R=0.76 respectively). Systolic backward flow and diastolic forward flow identified marked systolic and diastolic FD (≥0.35) with a positive likelihood ratio of 6.0 and 10.8, respectively. In conclusion, conventional PC-FRC data can detect and quantify FD in patients with AR suggesting the curves as a research and screening tool in larger patient populations.
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| 8. |
- Bech-Hanssen, Odd, 1956, et al.
(författare)
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Pulsed-Wave Doppler Recordings in the Proximal Descending Aorta in Patients with Chronic Aortic Regurgitation: Insights from Cardiovascular Magnetic Resonance
- 2018
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 0894-7317. ; 31:3
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Tidskriftsartikel (refereegranskat)abstract
- The pulsed-wave Doppler recording in the descending aorta (PWD DAO ) is one of the parameters used in grading aortic regurgitation (AR) severity. The aim of the present study was to investigate the assessment of chronic AR by PWD DAO with insights from cardiovascular magnetic resonance (CMR). Methods: This prospective study comprised 40 patients investigated with echocardiography and CMR within 4 hours either prior to valve surgery (n = 23) or as part of their follow-up (n = 17) due to moderate or severe AR. End-diastolic flow velocity (EDFV) and the diastolic velocity time integral (dVTI) were measured. The appearance of diastolic forward flow (DFF) was noted. Phase-contrast flow rate curves were obtained in the DAO. Results: Twenty-five patients had severe and eight had moderate AR by echocardiography (seven were indeterminate). The EDFV was below the recommended threshold ( > 20 cm/sec) in 13 patients (52%) with severe AR. Lowering the EDFV threshold ( > 13 cm/sec) and with a dVTI threshold > 13 cm showed negative likelihood ratios of 0.27 and 0.09, respectively. Detection of DFF with PWD DAO identified a nonuniform velocity profile by CMR with positive and negative likelihood ratios of 7.0 and 0.19, respectively. The relation between EDFV and DAO regurgitant volume (DAO-RVol CMR ) was strong in patients without (R = 0.88) and weak in patients with DFF (R = 0.49). The DAO-RVol CMR as a percent of the total RVol CMR decreased with increasing ascending aorta (AAO) size and increased with increasing AR severity. Conclusions: Our findings suggest that PWD DAO provides semiquantitative parameters useful to assess chronic AR severity. The limitations are related to nonuniform velocity contour and variable degree of lower body contribution, which depends on AR severity but also on the AAO size.
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| 9. |
- Gao, Sinsia, 1966, et al.
(författare)
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Evaluation of the Integrative Algorithm for Grading Chronic Aortic and Mitral Regurgitation Severity Using the Current American Society of Echocardiography Recommendations: To Discriminate Severe from Moderate Regurgitation.
- 2018
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Ingår i: Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography. - : Elsevier BV. - 1097-6795. ; 31:9
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Tidskriftsartikel (refereegranskat)abstract
- The recently published integrative algorithms for echocardiographic grading of native aortic regurgitation (AR) and mitral regurgitation (MR) by the American Society of Echocardiography are consensus based and have not been evaluated. Thus, the aims of the present study were to investigate the feasibility of individual parameters and to evaluate the ability of the algorithms to discriminate severe from moderate regurgitation.This prospective study comprised 93 patients with chronic AR (n=45) and MR (n=48). All patients underwent echocardiography and cardiovascular magnetic resonance within 4hours. The algorithms were evaluated using two different definitions for severe regurgitation: (1) a cardiovascular magnetic resonance standard indicating future need for valve surgery and (2) a clinical standard using patients who underwent valve surgery with proven postoperative left ventricular reverse remodeling and improved functional class (AR/MR, n = 26/26).The feasibility of the criteria in the first step of the algorithm was higher (AR/MR, 95%/91%) compared with the second step using quantitative Doppler parameters (74%/57%). For the AR algorithm, sensitivity was 95% and specificity 44%, whereas for the MR algorithm, sensitivity was 73% and specificity 92%. Among patients with benefit of surgery, the algorithms correctly identified 77%, misclassified 8%, and were inconclusive in 15% of the patients with AR; the corresponding figures were 73%, 15%, and 12% in the patients with MR.Using cardiovascular magnetic resonance as reference, the recommended algorithms for grading of regurgitation have the ability to rule out severe AR and rule in severe MR. The quantitative Doppler methods are hampered by feasibility issues, and our findings suggest that the decision regarding surgical intervention in symptomatic patients with discordant or inconclusive echocardiographic grading should be based on a consolidated assessment of clinical and multimodality findings.
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| 10. |
- Hebelka, Hanna, 1977, et al.
(författare)
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Axial loading during MRI induces significant T2 value changes in vertebral endplates-a feasibility study on patients with low back pain
- 2018
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Ingår i: Journal of Orthopaedic Surgery and Research. - : Springer Science and Business Media LLC. - 1749-799X. ; 13:18
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Tidskriftsartikel (refereegranskat)abstract
- Background: The function of the endplate (EP) is the most important factor influencing nutritional supply to the avascular intervertebral disc (IVD). It is desired to have a non-invasive method to assess functional EP characteristics in vivo. Assessment of functional EP characteristics is important in order to understand its relation to IVD degeneration, which in turn might deepen the understanding of the pathophysiology behind low back pain (LBP). It was hypothesized that, by comparing quantitative MRI of EPs performed with conventional supine MRI (unloaded MRI) with axial loading during MRI (alMRI), dynamical properties of the EP can be displayed. The aim was therefore to investigate the feasibility of axial loading during MRI (alMRI) to instantaneously induce quantitative EP changes. Methods: T2 mapping of 55 vertebral EPs (L1-S1) in five LBP patients was performed during conventional supine MRI (unloaded MRI) and subsequent alMRI. With T2 mapping, the cartilaginous EP and bony EP cannot be separated; hence, the visualized EP was termed EP zone (EPZ). Each EPZ was segmented at multiple midsagittal views, generating volumetric regions of interest. EPZs demonstrating signal inhomogeneity and/or adjacent Modic changes (MC) were termed abnormal EPZs. EPZ mean T2 values were compared between unloaded MRI and alMRI, and their relationship with abnormal EPZs was determined. Results: alMRI induced significantly higher (p = 0.01) EPZ mean T2 values compared with unloaded MRI. Significantly higher mean T2 values were seen in inferior EPZs compared with superior EPZs, both with unloaded MRI (35%, p < 0.001) and with alMRI (26%, p = 0.04). Significant difference between unloaded MRI and alMRI was seen in normal (p = 0.02), but not in abnormal EPZs (p = 0.5; n = 12). Conclusions: alMRI induces changes in human EPZ characteristics in vivo. The T2 value significantly increased in normal EPZs, with lack of such in abnormal EPZs. Combining T2 mapping with alMRI provides a clinical feasible, non-invasive method with potential to reveal biochemical behavioral patterns, thus adding another dimension of the EPZs characteristics compared with information obtained with solely unloaded MRI.
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| 11. |
- Hebelka, Hanna, 1977, et al.
(författare)
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Axial loading during MRI reveals deviant characteristics within posterior IVD regions between low back pain patients and controls
- 2018
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Ingår i: European Spine Journal. - : Springer Science and Business Media LLC. - 0940-6719 .- 1432-0932. ; 27:11, s. 2840-2846
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To investigate differences in functional intervertebral disk (IVD) characteristics between low back pain (LBP) patients and controls using T2-mapping with axial loading during MRI (alMRI). Methods In total, 120 IVDs in 24 LBP patients (mean age 39years, range 25-69) were examined with T2-mapping without loading of the spine (uMRI) and with alMRI (DynaWell((R)) loading device) and compared with 60 IVDs in 12 controls (mean age 38 years, range 25-63). The IVD T2-value was acquired after 20-min loading in five regions of interests (ROI), ROI1-5 from anterior to posterior. T2-values were compared between loading states and cohorts with adjustment for Pfirrmann grade. Results In LBP patients, mean T2-value of the entire IVD was 64 ms for uMRI and 66 ms for alMRI (p = 0.03) and, in controls, 65 ms and 65 ms (p = 0.5). Load-induced T2-differences (alMRI-uMRI) were seen in all ROIs in both patients (0.001>p<0.005) and controls (0.0001>p<0.03). In patients, alMRI induced an increase in T2-value for ROI1-3 (23%, 18% and 5%) and a decrease for ROI4 (3%) and ROI5 (24%). More pronounced load-induced decrease was detected in ROI4 in controls (9%/p=0.03), while a higher absolute T2-value was found for ROI5 during alMRI in patients (38 ms) compared to controls (33 ms) (p = 0.04). Conclusion The alMRI-induced differences in T2-value in ROI4 and ROI5 between patients and controls most probably indicate biomechanical impairment in the posterior IVD regions. Hence, alMRI combined with T2-mapping offers an objective and clinical feasible tool for biomechanical IVD characterization that may deepen the knowledge regarding how LBP is related to altered IVD matrix composition.
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| 12. |
- Hedelin, Henrik, 1975, et al.
(författare)
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Innominate salter osteotomy using resorbable screws: A retrospective case series and presentation of a new concept for fixation
- 2019
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Ingår i: Journal of Children's Orthopaedics. - : SAGE Publications. - 1863-2521 .- 1863-2548. ; 13:3, s. 310-317
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, British Editorial Society of Bone and Joint Surgery. All rights reserved. Purpose The Salter innominate osteotomy (SIO) in children is traditionally stabilized by Kirschner-wires, which have issues regarding stability, infection and the need to be extracted. To counter these disadvantages, we present a surgical method to stabilize SIO with modern resorbable poly lactic-co-glycolic acid screws. Using a case series of 21 patients treated with SIO for developmental dysplasia of the hip or Legg-Calvé- Perthes disease we evaluate the feasibility of the method. Methods The integrity of the osteotomy was interpreted by radiological measurements of acetabular index, centre-edge angle and Reimer’s index. Perioperative and postoperative complications were evaluated. Results Radiographic evaluation revealed a stable osteotomy and favourable development in all measured parameters with the exception of one patient who fell out of bed the first day postoperatively. No other perioperative surgical complications were observed and there were no local reactions to the resorbable screws. Conclusion Modern resorbable screws carry multiple benefits both for the patient and the surgeon. In our case series the implants provided sufficient stability and the implants caused no local reactions. The use of resorbable implants gave the surgeon a wider range of possible screw placements and avoided the need for implant removal.
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| 13. |
- Lagerstrand, Kerstin M, et al.
(författare)
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Low back pain patients and controls display functional differences in endplates and vertebrae measured with T2-mapping
- 2019
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Ingår i: European Spine Journal. - : Springer Science and Business Media LLC. - 0940-6719 .- 1432-0932. ; 28:2, s. 234-240
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Tidskriftsartikel (refereegranskat)abstract
- © 2018, The Author(s). Purpose: The aim was to (1) verify our previous finding that endplates (EPs) display load-induced T2-changes, (2) investigate whether vertebrae display load-induced T2-changes and (3) investigate whether EPs and vertebrae in LBP patients and controls display T2-differences during conventional unloaded MRI and axial loaded MRI (alMRI). Methods: Twenty-seven patients (mean 39years) and 12 (mean 38years) controls were examined with T2-mapping on a 1.5T scanner during conventional unloaded MRI and subsequently during alMRI (Dynawell® loading device), separated by approximately 20min. For determination of EP and vertebral T2-values, volumetric regions of interest were manually segmented. Each vertebra was then divided into half to obtain superior and inferior units. The presence of EP changes (visual inhomogeneity in the EP zone), Schmorl’s nodules and Modic changes were registered. Results: For conventional unloaded MRI, the T2-values in the superior and inferior vertebral units and the EPs were significantly higher in the patients compared with controls (p < 0.03, p < 0.006) even when adjusted for the presence of Modic changes, Schmorl’s nodules and EP signal changes. alMRI induced significant changes in the superior EPs of the patients (p < 0.001). Additionally, the T2-value differed significantly between the superior and inferior EP, as well as between the superior and inferior vertebra with higher values in the inferior units (p < 0.001). Conclusion: This study demonstrated significantly higher EP and vertebral T2-values in LBP patients in comparison with controls. In addition, alMRI induced significant T2-changes in the superior EPs for patients but not for controls. Importantly, the T2-differences between the groups may indicate that EPs and vertebrae in LBP patients have altered biodynamical characteristics compared to controls and the higher T2-values measured in patients may represent early inflammation or impaired nutritional transport. Graphical abstract: These slides can be retrieved from electronic supplementary material.[Figure not available: see fulltext.]
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| 14. |
- Nilsson, Martin, 1966, et al.
(författare)
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Axial loading during MRI influences T2-mapping values of lumbar discs: a feasibility study on patients with low back pain
- 2016
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Ingår i: European Spine Journal. - : Springer Science and Business Media LLC. - 0940-6719 .- 1432-0932. ; 25:9, s. 2856-2863
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Tidskriftsartikel (refereegranskat)abstract
- To investigate whether axial loading of the spine during MRI (alMRI) instantaneously induces changes in biochemical disc features as reflected by altered quantitative T2 values in patients with chronic low back pain (LBP). T2 mapping was performed on 11 LBP patients (54 lumbar discs) during the conventional unloaded MRI and subsequent alMRI. Each disc was divided into five volumetric regions of interests (ROIs), anterior annulus fibrosus (AF) (ROI 1), the interface anterior AF-nucleus pulposus (NP) (ROI 2), NP (ROI 3), the interface NP-posterior AF (ROI 4), and the posterior AF (ROI 5). The mean T2 values for each ROI were compared between MRI and alMRI and correlated with degeneration grade (Pfirrmann), disc angle, and disc level. With alMRI, T2 values increased significantly in the whole disc as well as in various parts of the disc with an increase in ROI 1-3 and a decrease in ROI 5. The changes in T2 values correlated to degeneration grade, changes in disc angle, and lumbar level. alMRI instantaneously induces T2-value changes in lumbar discs and is, thus, a feasible method to reveal dynamic, biochemical disc features in patients with chronic LBP.
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| 15. |
- Polte, Christian Lars, et al.
(författare)
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Characterization of Chronic Aortic and Mitral Regurgitation Undergoing Valve Surgery Using Cardiovascular Magnetic Resonance.
- 2017
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Ingår i: The American journal of cardiology. - : Elsevier BV. - 1879-1913 .- 0002-9149. ; 119:12, s. 2061-2068
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Tidskriftsartikel (refereegranskat)abstract
- Grading of chronic aortic regurgitation (AR) and mitral regurgitation (MR) by cardiovascular magnetic resonance (CMR) is currently based on thresholds, which are neither modality nor quantification method specific. Accordingly, this study sought to identify CMR-specific and quantification method-specific thresholds for regurgitant volumes (RVols), RVol indexes, and regurgitant fractions (RFs), which denote severe chronic AR or MR with an indication for surgery. The study comprised patients with moderate and severe chronic AR (n= 38) and MR (n= 40). Echocardiography and CMR was performed at baseline and in all operated AR/MR patients (n= 23/25) 10 ± 1months after surgery. CMR quantification of AR: direct (aortic flow) and indirect method (left ventricular stroke volume [LVSV]- pulmonary stroke volume [PuSV]); MR: 2 indirect methods (LVSV- aortic forward flow [AoFF]; mitral inflow [MiIF]- AoFF). All operated patients had severe regurgitation and benefited from surgery, indicated by a significant postsurgical reduction in end-diastolic volume index and improvement or relief of symptoms. The discriminatory ability between moderate and severe AR was strong for RVol >40ml, RVol index >20ml/m(2), and RF >30% (direct method) and RVol >62ml, RVol index >31ml/m(2), and RF >36% (LVSV-PuSV) with a negative likelihood ratio ≤ 0.2. In MR, the discriminatory ability was very strong for RVol >64ml, RVol index >32ml/m(2), and RF >41% (LVSV-AoFF) and RVol >40ml, RVol index >20ml/m(2), and RF >30% (MiIF-AoFF) with a negative likelihood ratio < 0.1. In conclusion, CMR grading of chronic AR and MR should be based on modality-specific and quantification method-specific thresholds, as they differ largely from recognized guideline criteria, to assure appropriate clinical decision-making and timing of surgery.
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| 16. |
- Polte, Christian Lars, et al.
(författare)
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Mitral regurgitation quantification by cardiovascular magnetic resonance: a comparison of indirect quantification methods
- 2015
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Ingår i: The International Journal of Cardiovascular Imaging. - : Springer Science and Business Media LLC. - 1569-5794 .- 1573-0743. ; 31:6, s. 1223-31
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Tidskriftsartikel (refereegranskat)abstract
- Quantification of mitral regurgitation (MR) using cardiovascular magnetic resonance can be achieved by three indirect methods. The aims of the study were to determine their agreement, observer variability and effect on grading MR severity. The study comprised 16 healthy volunteers and 36 MR patients. Quantification was performed using the 'standard' [left ventricular stroke volume (LVSV)-aortic forward flow (AoFF)], 'volumetric' [LVSV-right ventricular stroke volume (RVSV)] and 'flow' method [mitral inflow (MiIF)-AoFF]. In healthy volunteers without MR, LVSV was larger than AoFF (mean difference ±SD: 12 ± 6 ml, P < 0.0001). Only small differences were found between LVSV-RVSV (3 ± 6 ml) and MiIF-AoFF (1 ± 5 ml). In patients, mitral regurgitant volumes (MRVs)/fractions (MRFs) were larger (P < 0.0001) using the 'standard' method (90 ± 31 ml/51 ± 11%) compared with the 'volumetric' (76 ± 30 ml/42 ± 11%) and 'flow' method (70 ± 32 ml/44 ± 15%). Inter-observer variability was lowest for the 'flow' and highest for the 'volumetric' method, while intra-observer variability was similar for all three methods. In 29 operated patients with severe MR, MRVs were above the guideline threshold (≥60 ml) in 100, 86 and 83% of the cases, and MRFs were above the threshold (≥50%) in 76, 32 and 48% of the cases, when using the 'standard', 'volumetric' and 'flow' method respectively. In conclusion, the choice of method can affect the grading of MR severity and thereby eventually the clinical decision-making and timing of surgery.
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| 17. |
- Polte, Christian Lars, et al.
(författare)
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Quantification of Left Ventricular Linear, Areal and Volumetric Dimensions: A Phantom and inVivo Comparison of 2-D and Real-Time 3-D Echocardiography with Cardiovascular Magnetic Resonance.
- 2015
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Ingår i: Ultrasound in medicine & biology. - : Elsevier BV. - 1879-291X .- 0301-5629. ; 41:7, s. 1981-1990
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional echocardiography and real-time 3-D echocardiography have been reported to underestimate human left ventricular volumes significantly compared with cardiovascular magnetic resonance. We investigated the ability of 2-D echocardiography, real-time 3-D echocardiography and cardiovascular magnetic resonance to delineate dimensions of increasing complexity (diameter-area-volume) in a multimodality phantom model and invivo, with the aim of elucidating the main cause of underestimation. All modalities were able to delineate phantom dimensions with high precision. Invivo, 2-D and real-time 3-D echocardiography underestimated short-axis end-diastolic linear and areal and all left ventricular volumetric dimensions significantly compared with cardiovascular magnetic resonance, but not short-axis end-systolic linear and areal dimensions. Underestimation increased successively from linear to volumetric left ventricular dimensions. When analyzed according to the same principles, 2-D and real-time 3-DE echocardiography provided similar left ventricular volumes. In conclusion, echocardiographic underestimation of left ventricular dimensions is due mainly to inherent technical differences in the ability to differentiate trabeculated from compact myocardium. Identical endocardial border definition criteria are needed to minimize differences between the modalities and to ensure better comparability in clinical practice.
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| 18. |
- Simrén, Yvonne, 1966, et al.
(författare)
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Renal swelling indicates renal damage in infants with their first urinary tract infection
- 2018
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253. ; 107:11, s. 2004-2010
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Tidskriftsartikel (refereegranskat)abstract
- Aim: We used ultrasound to evaluate renal swelling as a predictor of acute and permanent renal damage in infants with their first urinary tract infection (UTI). Methods: The cohort at the Queen Silvia Children's Hospital, Gothenburg, Sweden, comprised 101 infants with their first UTI at a mean age of 3.9 +/- 3.0 months. Acute and follow-up ultrasounds were carried out a few days and one month after treatment started, and a (99m)technetium dimercaptosuccinic acid (DMSA) scan was carried out after one month and after a year if the first scan was abnormal. Results: The acute ultrasounds showed that renal length and volume, calculated as standard deviation scores (SDS), were 1.39 +/- 1.43 SDS and 1.30 +/- 1.08 SDS. We found that 52% of the one-month DMSA scans and 25% of the one-year DMSA scans were abnormal. Renal length (p = 0.0026) and initial volume (p = 0.0005) on the ultrasound predicted acute renal damage at the one-month DMSA scan and initial renal length (p = 0.030) predicted permanent renal damage at the one-year DMSA scan. Conclusion: Renal swelling was associated with renal damage. Although the diagnostic performance compared with the DMSA scan was weak, renal swelling may help clinicians to make decisions about further investigations and follow-ups of infants with UTIs.
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| 19. |
- Simrén, Yvonne, 1966, et al.
(författare)
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Ultrasound is an effective and noninvasive method of evaluating renal swelling in infants with their first urinary tract infection
- 2017
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253. ; 106:11, s. 1868-1874
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Tidskriftsartikel (refereegranskat)abstract
- Aim: This study evaluated renal swelling in infants with a first urinary tract infection (UTI) by correlating renal length and volume with C-reactive protein (CRP) and body temperature. Methods: Ultrasounds were carried out on 104 infants at The Queen Silvia Children's Hospital, Gothenburg, Sweden - 58 boys (mean age 3.3 months) and 46 girls (mean age 4.8 months) - during the acute phase of their UTI. A second scan was performed on 94 of them 4 weeks later. Renal length and volume were computed to standard deviation scores (SDS). Results: The mean renal length and volume at the first ultrasound were 1.90 SDS (1.54) and 1.67 SDS (+/- 1.13) for the larger kidney and 0.86 SDS (+/- 1.01) and 0.84 SDS (+/- 0.90) for the smaller kidney. There was a significant decrease in renal length and volume between the two ultrasounds, with a mean difference of 0.96 SDS (+/- 1.24) and 1.07 SDS (+/- 1.10) for the larger kidney (p < 0.0001). The length and volume of the larger kidney correlated with CRP (p < 0.001), but only the renal length correlated with fever (p < 0.001). Conclusion: Early ultrasound determined renal swelling in infants with a UTI and may be a valuable noninvasive way of identifying infants with renal parenchymal involvement.
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| 20. |
- Torén, Leif, et al.
(författare)
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With axial loading during MRI diurnal T2-value changes in lumbar discs are neglectable: A cross sectional study
- 2018
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Ingår i: BMC Musculoskeletal Disorders. - : Springer Science and Business Media LLC. - 1471-2474. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Axial loading during MRI (alMRI) combined with T2 mapping recently was shown as a promising method to reveal biomechanical intervertebral disc (IVD) characteristics. This feasibility study aims to investigate whether there is a diurnal variation in the IVD T2-value when using alMRI. This is of importance for the planning of when to perform alMRI investigations and for interpretations of alMRI findings in relation to clinical symptoms. Methods: Six healthy volunteers (30 lumbar discs), were examined with alMRI at three different sessions during 1 day. To be representative for a low back pain cohort in terms of age and IVD degeneration the included participants had a wide age range (27-63y) and all Pfirrmann grades represented. The T2-values were measured in five IVD regions of interest (ROI). The ROIs were equally large in sagittal plane with ROI1 representing anterior parts of the IVD, ROI5 posterior IVD parts and ROI2-4 the parts in between. Results: T2-values of the entire IVD varied between 38 and 138 ms at 7 am, 33-143 ms at 11.30 am, and 31-147 ms at 4 pm with large regional IVD variations at all time points. No significant alterations of the T2-values over the day were found, neither for the entire IVD (p = 0.4) nor for the various ROIs (p = 0.2-1.0). Neither when correlated to Pfirrmann grade, any significant diurnal T2-value changes were found. Conclusions: With alMRI, only minor diurnal T2-value changes were found in the lumbar discs. Nonsignificant and neglectable diurnal changes are advantageous both for research purposes, as well as in the clinical setting, giving comparable and robust data regardless of at what time-point the alMRI is performed. © 2018 The Author(s).
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| 21. |
- Waldenberg, Christian, 1987, et al.
(författare)
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Differences in IVD characteristics between low back pain patients and controls associated with HIZ as revealed with quantitative MRI
- 2019
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 14:8
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Tidskriftsartikel (refereegranskat)abstract
- Background Magnetic resonance imaging (MRI) can provide objective continuous intervertebral disc (IVD) measures in low back pain (LBP) patients. However, there are limited studies comparing quantitative IVD measures of symptomatic and asymptomatic individuals. This study aimed to investigate possible differences in IVD tissue composition in patients with chronic LBP and controls using quantitative MRI and correlate IVD measures with the phenotype High-Intensity Zone (HIZ). The lumbar spine of 25 LBP-patients (25-69y, mean 38y, 11 males) and 12 controls (25-59y, mean 38y, 7 males) was examined with T2-mapping on a 1.5T MRI scanner. The mean T2-map value and standard deviation were determined in three midsagittal IVD slices and five sub-regions dividing each IVD in the sagittal plane. The distribution of T2-map values over the IVD was also determined with histogram analysis (Delta mu = distribution width). When compared to controls, patient IVDs displayed lower values for all metrics, with significant differences for the T2-map value, standard deviation (p = 0.026) and Delta mu (p = 0.048). Significantly different T2-map values were found between cohorts in the region representing nucleus pulposus and the border zone between nucleus pulposus and posterior annulus fibrosus (p = 0.047-0.050). Excluding all IVDs with HIZs resulted in no significant difference between the cohorts for any of the analyzed metrics (p = 0.053-0.995). Additionally, the T2-map values were lower in patients with HIZ in comparison without HIZ. Differences in IVD characteristics, measured with quantitative MRI, between LBP patients and controls were found. The T2-differences may reflect altered IVD function associated with HIZ. Future studies are recommended to explore IVD functionality in relation to HIZ and LBP.
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| 22. |
- Waldenberg, Christian, 1987, et al.
(författare)
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MRI histogram analysis enables objective and continuous classification of intervertebral disc degeneration.
- 2018
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Ingår i: European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. - : Springer Science and Business Media LLC. - 1432-0932. ; 27:5, s. 1042-1048
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic resonance imaging (MRI) is the best diagnostic imaging method for low back pain. However, the technique is currently not utilized in its full capacity, often failing to depict painful intervertebral discs (IVDs), potentially due to the rough degeneration classification system used clinically today. MR image histograms, which reflect the IVD heterogeneity, may offer sensitive imaging biomarkers for IVD degeneration classification. This study investigates the feasibility of using histogram analysis as means of objective and continuous grading of IVD degeneration.Forty-nine IVDs in ten low back pain patients (six males, 25-69years) were examined with MRI (T2-weighted images and T2-maps). Each IVD was semi-automatically segmented on three mid-sagittal slices. Histogram features of the IVD were extracted from the defined regions of interest and correlated to Pfirrmann grade.Both T2-weighted images and T2-maps displayed similar histogram features. Histograms of well-hydrated IVDs displayed two separate peaks, representing annulus fibrosus and nucleus pulposus. Degenerated IVDs displayed decreased peak separation, where the separation was shown to correlate strongly with Pfirrmann grade (P<0.05). In addition, some degenerated IVDs within the same Pfirrmann grade displayed diametrically different histogram appearances.Histogram features correlated well with IVD degeneration, suggesting that IVD histogram analysis is a suitable tool for objective and continuous IVD degeneration classification. As histogram analysis revealed IVD heterogeneity, it may be a clinical tool for characterization of regional IVD degeneration effects. To elucidate the usefulness of histogram analysis in patient management, IVD histogram features between asymptomatic and symptomatic individuals needs to be compared.
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