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- Newman, David, et al.
(författare)
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Test–retest reliability of rapid whole body and compartmental fat volume quantification on a widebore 3T MR system in normal-weight, overweight, and obese subjects
- 2016
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley-Blackwell. - 1053-1807 .- 1522-2586. ; 44:6, s. 1464-1473
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo measure the test–retest reliability of rapid (<15 min) whole body and visceral fat volume quantification in normal and obese subjects on a widebore 3T MR system and compare it with conventional manual segmentation.Materials and MethodsThirty participants (body mass index [BMI] 20.1–48.6 kg/m2) underwent two whole-body magnetic resonance imaging (MRI) examinations on a widebore 3T machine using a 2-point Dixon technique. Phase sensitive reconstruction and intensity inhomogeneity correction produced quantitative datasets of total adipose tissue (TAT), abdominal subcutaneous adipose tissue (ASAT), and visceral adipose tissue (VAT). The quantification was performed automatically using nonrigid atlas-based segmentation and compared with manual segmentation (SliceOmatic).ResultsThe mean TAT was 31.74 L with a coefficient of variation (CV) of 0.79% and a coefficient of repeatability (CR) of 0.49 L. The ASAT was 7.92 L with a CV of 2.98% and a CR of 0.46 L. There was no significant difference in the semiautomated and manually segmented VAT (P = 0.73) but there were differences in the reliability of the two techniques. The mean semiautomated VAT was 2.56 L, CV 1.8%, and CR 0.09 L compared to the mean manually segmented VAT of 3.12 L, where the CV was 6.3% and the CR was 0.39 L.ConclusionRapid semiautomated whole body and compartmental fat volume quantification can be derived from a widebore 3T system, for a range of body sizes including obese patients, with “almost perfect” test–retest reliability.
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| 2. |
- Petridou, Elia, et al.
(författare)
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Breast fat volume measurement in a wide-bore 3T MR: comparison of traditional mammographic density evaluation with MR density measurements using automatic segmentation.
- 2017
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Ingår i: Clinical Radiology. - : Saunders Elsevier. - 0009-9260 .- 1365-229X. ; 72:7, s. 565-572
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Tidskriftsartikel (refereegranskat)abstract
- AimTo compare magnetic resonance imaging (MRI) derived breast density measurements using automatic segmentation algorithms with radiologist estimations using the Breast Imaging Reporting and Data Systems (BI-RADS) density classification.Materials and Methods40 women undergoing mammography and dynamic breast MRI as part of their clinical management were recruited. Fat-water separated MR images derived from a 2-point Dixon technique, phase sensitive reconstruction and atlas based segmentation were obtained before and after intravenous contrast. Breast density was assessed using software from Advanced MR Analytics (AMRA), Linköping, Sweden with results compared to the widely used four-quartile quantitative BIRADS scale.ResultsThe proportion of glandular tissue of the breast on MRI was derived from the AMRA sequence. The mean unenhanced breast density was 0.31 ± 0.22 (mean ± SD) (left) and 0.29 ± 0.21 (right). Mean breast density on post-contrast images was 0.32 ± 0.19 (left) and 0.32 ± 0.2 (right). There was "almost perfect" correlation between pre and post-contrast breast density quantification: Spearman correlation rho=0.98 (95% confidence intervals (CI): 0.97-0.99) (left) and rho=0.99(CI: 0.98-0.99) (right). The 95% limits of agreement were -0.11-0.08 (left) and -0.08-0.03 (right).Interobserver reliability for BIRADS is "substantial": weighted Kappa k=0.8 (CI: 0.74- 0.87). The Spearman Correlation coefficient between BIRADs and MR breast density was rho=0.73 (CI: 0.60-0.82) (left) and rho=0.75 (CI: 0.63-0.83) (right) which is also "substantial".ConclusionThe AMRA sequence provides a fully automated, reproducible, objective assessment of fibroglandular breast tissue proportion that correlates well with mammographic assessment of breast density with the added advantage of avoidance of ionising radiation.
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| 3. |
- Thomas, Marianna S, et al.
(författare)
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Test-retest reliability of automated whole body and compartmental muscle volume measurements on a wide bore 3T MR system
- 2014
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Ingår i: European Radiology. - : Springer Berlin/Heidelberg. - 0938-7994 .- 1432-1084. ; 24:9, s. 2279-2291
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:To measure the test-retest reproducibility of an automated system for quantifying whole body and compartmental muscle volumes using wide bore 3 T MRI.MATERIALS AND METHODS:Thirty volunteers stratified by body mass index underwent whole body 3 T MRI, two-point Dixon sequences, on two separate occasions. Water-fat separation was performed, with automated segmentation of whole body, torso, upper and lower leg volumes, and manually segmented lower leg muscle volumes.RESULTS:Mean automated total body muscle volume was 19·32 L (SD9·1) and 19·28 L (SD9·12) for first and second acquisitions (Intraclass correlation coefficient (ICC) = 1·0, 95 % level of agreement -0·32-0·2 L). ICC for all automated test-retest muscle volumes were almost perfect (0·99-1·0) with 95 % levels of agreement 1.8-6.6 % of mean volume. Automated muscle volume measurements correlate closely with manual quantification (right lower leg: manual 1·68 L (2SD0·6) compared to automated 1·64 L (2SD 0·6), left lower leg: manual 1·69 L (2SD 0·64) compared to automated 1·63 L (SD0·61), correlation coefficients for automated and manual segmentation were 0·94-0·96).CONCLUSION:Fully automated whole body and compartmental muscle volume quantification can be achieved rapidly on a 3 T wide bore system with very low margins of error, excellent test-retest reliability and excellent correlation to manual segmentation in the lower leg.KEY POINTS:• Sarcopaenia is an important reversible complication of a number of diseases. • Manual quantification of muscle volume is time-consuming and expensive. • Muscles can be imaged using in and out of phase MRI. • Automated atlas-based segmentation can identify muscle groups. • Automated muscle volume segmentation is reproducible and can replace manual measurements.
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