Fig. 2
Volumetric synovitis assessment. a Left part of figure shows transverse T1-weighted fat suppressed contrast enhanced (T1-FS CE) image at Level 2 (see Fig. 1a). Segmented synovium is depicted in red. Note perisynovitic inflammatory infiltration of soft tissues. Right part of figure shows corresponding FLAIR-FS image with synovium being segmented at the same level and colored in green. Volume assessment was performed for all slices between Level 1 and Level 3 (inclusive of Level 1 and 3) in the cranio-caudal dimension. b Comparison of volume measurements for T1-FS CE images and FLAIR-FS for all knees analyzed. Note the persistently lower volume assessments for FLAIR-FS. Peripatellar synovial volume obtained from axial FLAIR-FS images was statistically significantly lower (p < 0.01) compared to T1-FS CE images ranging between 5.37 and 11.59 cm3 compared to 6.22 and 14.74 cm3 for T1-FS CE images. The mean difference between the two sequences was 19% less synovial volume for FLAIR-FS