Department of Clinical Research, MR-Spectroscopy and Methodology, University of Bern, Bern, Switzerland.
J Magn Reson Imaging. 2012 Oct;36(4):951-60. doi: 10.1002/jmri.23707. Epub 2012 May 29.
To investigate the inhomogeneity of radiofrequency fields at higher field strengths that can interfere with established volumetric methods, in particular for the determination of visceral (VAT) and subcutaneous adipose tissue (SCAT). A versatile, interactive sparse sampling (VISS) method is proposed to determine VAT, SCAT, and also total body volume (TBV).
VISS is based on a separation of major components by contour lines, followed by a sparse sampling algorithm, and eventually a quick manual correction. T1-weighted whole body scans of 24 subjects were evaluated (12 at 1.5T, 12 at 3.0T).
(a) Coefficients of variance (CV) and intra class correlation coefficients (ICC) determined within 3 raters (24 subjects) showed high consistency for SCAT (CV 2.2%, ICC 0.993) and VAT (CV 4.9%, ICC 0.987), (b) comparison with an established volumetric method revealed good agreement (Bland-Altman, VAT -0.68L to 1.07L, SCAT -2.18L to 8.39L), and (c) comparison of weights calculated from TBV with values measured on a scale resulted in an even better accuracy for VISS (Bland-Altman -1.98 kg to 4.09 kg) than for the reference method (-5.60 kg to 1.60 kg).
VISS is reproducible in particular within the same rater, accurate as compared with established methods, and robust against low contrast and inhomogeneity artifacts.
研究在更高场强下可能干扰已建立的容积方法的射频场不均匀性，特别是用于确定内脏（VAT）和皮下脂肪组织（SCAT）。提出了一种通用的交互式稀疏采样（VISS）方法，用于确定 VAT、SCAT 以及总身体体积（TBV）。
VISS 基于通过轮廓线分离主要成分，然后是稀疏采样算法，最终是快速手动校正。评估了 24 名受试者的 T1 加权全身扫描（12 名在 1.5T，12 名在 3.0T）。
（a）在 3 名评估者（24 名受试者）内确定的变异系数（CV）和组内相关系数（ICC）显示出 SCAT 的高度一致性（CV 2.2%，ICC 0.993）和 VAT（CV 4.9%，ICC 0.987），（b）与已建立的容积方法的比较显示出良好的一致性（Bland-Altman，VAT-0.68L 至 1.07L，SCAT-2.18L 至 8.39L），（c）TBV 计算的重量与秤上测量的值的比较导致 VISS 的准确性甚至更好（Bland-Altman-1.98 千克至 4.09 千克）比参考方法（-5.60 千克至 1.60 千克）。
VISS 在同一评估者内具有可重复性，与已建立的方法相比准确，并且对低对比度和不均匀性伪影具有鲁棒性。
