“…Gray-scale signal threshold semi-automatically determined for each region based on user selected small region of muscleMuscle volume = total volume – fat volume | Bhadresha et al, 2016 [19] | 2 raters ( n = 20); inter-rater ICC = 0.33–0.76, Cronbach’s alpha = 0.59–0.91 | T2 FSE | I slice per level at IVD L3-4, L4-5, L5-S1 | MF, ES, PS | Visual inspection | 18×27 (1 cm apart) grid applied to image. By visual inspection: # of grid points touching fat vs. muscle counted | Muscle to Fat Ratio= Muscle/#fat pixels |
Crawford et al, 2016 [5] | No | 2-point DIXON (3D fast-field echo T1) whole body | Every 3 rd slice L1-L5 (with interpolation to full volume) | MF, ES | Semiautomatic segmentation with linear interpolation (Myrian Intrasense, Paris, France) | Semi-automated ROI from water to fat image | Fat signal fraction (FSF) = (Signalfat/[Signalwater + Signalfat])*100 |
D’Hooge et al, 2012 [10] | No | T1 FSE | 1 slice per level at L3 superior endplate, L4 superior endplate, L4 inferior endplate | MF, ES, PS | ImageJ manual trace | Automated based on pixel intensity gray-scale threshold | MFI = (signal intensity of “lean muscle”)/(signal intensity of user defined fat ROI) |
Fortin et al, 2014 [13] | 1 rater; intra-rater: ICC = 0.90 –0.96) | T2 | 1 slice per level at IVD L3-4 and L5-S1 | MF, ES, MF + ES | ImageJ manual trace following fascial borders | User selected pixel intensity gray-scale threshold selected from 4–6 sample ROIs within visible ‘lean muscle’ | FCSA = (CSAFat)/(CSATotal); Proportion estimate of muscle fat content = Average signal intensity of Total ROI |
Hebert et al, 2014 [18] | 1 rater; intra-rater ( n = 30) ICC (3,1) = 0.93, Bias = −0.70, 95% LOA = −8.11–6.72 | T1 SE (0.2 Tesla) | 1 slice per level at L4 and L5 | MF | Manual trace | Custom MatLab script; threshold set from midpoint between histogram peaks for ‘fat and muscle’ | % IMAT = CSAFat/CSATotal (IMAT = intramuscular adipose tissue) |
Hu et al, 2011 [54] | 3 raters ( n = 29); intra-rater ICC (3,1) for FCSA = 0.832–0.847, for T2 SI = 0.926–0.957; inter-rater CC for FCSA = 0.858–0.894, for T2 SI = 0.891–0.923 | T2 FSE | 1 slice per level at IVD L3-4, L4-5, L5-S1 | MF, ES | PACS workstation manual trace: lean muscle CSA Drawn avoiding visible fat; Fat% - following outer perimeter | PACS embedded ROI and gray-scale histogram software calculated from mean T2 signal intensity | Lean muscle FCSA = Manually traced Muscle CSA Fat Infiltration = T2 signal intensity |
Kjaer et al, 2007 [8] | 2 raters ( n = 50); intra-rater k = 0.86; inter-rater k = 0.58 | T1 SE (0.2 Tesla) | 1 slice per level at IVD L3-4, L4-5, L5-S1 | ...
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