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

Abstract

, 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 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 wide bore 3T MR system and compare with conventional manual segmentation. Materials and MethodsThirty participants (BMI 20.1-48.6 kg/m 2 ) underwent two whole body MRI examinations on a wide bore 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 non-rigid 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 semi-automated 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 semi-automated whole body and compartmental fat volume quantification can be derived from a wide bore 3T system, for a range of body sizes including obese patients, with "almost perfect" test-retest reliability.

Fat-Referenced MRI: Quanitaive MRI for Tissue Characterizaion and Volume Measurement

“…In a first analysis of regional muscle volume, Thomas et al [68] showed that the limits of agreement (the 95 % confidence interval of test-retest differences) between whole-body muscle measurements was as low as -0.35 L to 0.2 L. There was also a good agreement with manual segmentations. In a second analysis of the images, that focused on AT quantification, Newman et al [70] found no significant difference in adipose volume between fat-referenced volumetry and manual segmentation of magnitude images. Furthermore, the reliability of the measurements did increase with fat-referenced volumetry.…”

“…This evaluation has however become outdated as both reference methods have been upgraded, and the water-fat swaps seen in paper I have become less common. The PSR algorithm has also been successfully used in a range of studies [32,[68][69][70][71][72][73][74][75][76][77][78]. These studies did not directly evaluate the performance of PSR.…”

“…However, they do show that the technical success rate is high. The test-retest types studies [68][69][70] are especially interesting, as any swaps in relevant regions would have resulted in outliers during the statistical analysis.…”

“…The MANA method is conservative and robust, as it is only based on weighted averages. A number of studies have also shown that MANA produces reproducible measurements [31,32,[68][69][70]98]. Within all of these evaluation studies, the same fairly large structures were analyzed, and it is likely that any errors introduced by calibration inaccuracy mostly resulted in systematic errors.…”

“…The quantitative images also allow faster and less complex image segmentation, as AT volumetry is largely unaffected by over segmentation of AT into LT. The measurements are also reproducible within scanners [32,[68][69][70]98], but more work is needed to asses the between scanner reproducibility.…”