Segmented T1 weighted echo-planar imaging in the abdomen and pelvis. Comparison with T1 TSE and T2 UTSE sequences

Purpose:To assess, quantitatively and qualitatively, the diagnostic value o f a segmented EPI T1W sequence compared to T1W and T2W TSE sequences. Material and methods: A prospective analysis of abdominal and pelvic MRI ex aminations of 70 patients (44 women, 26 men, mean age of 61 years), was per formed on a 0.5 T supraconductive magnet with 15 mT/m gradients. The sequences were randomized and compared in a blinded fashion by 3 indepe ndent reviewers :TSE TIW (TR/TE = 500/ 12 ms, NSA = 6, turbo factor 5, 3 : 49 min), EPI T1W (TR/TE = 500/30 ms, NSA = 6, EPI factor = 7, 2 : 13 min) a nd UTSE T2W (TR/TE = 1600-2500/100, NSA = 6, turbo factor = 31, 2 : 20 min) . Results : Quantitatively, no significant difference was found between T1W s equences for signal to noise ratio. The EPI T1W sequence had lower signal b ut stronger enhancement after gadolinium injection. Qualitatively, EPI TIW had significantly less flow artefacts (p < 0.001, wi lcoxon test), and more chemical shift artifact (p < 0.01). For lesion detection, differences were not statistically significant betwee n T1W sequences or between paired T1W and T2W sequences (sensitivity and sp ecificity 84 and 86 % for TSE T1W 76 and 86 % for EPI T1W, 78 and 79 % for UTSE T2W, 90 and 65 % for TSE T1W-UTSE T2W, 88 and 65 % for EPI T1W-UTSE T2 W). Kappa concordance test (0.686) and Mac Nemar symmetry test (3.55) were high between T1W sequences. Conclusion :The segmented EPI T1W sequence used had equivalent results comp ared to the TSE T1W sequence, it allows a 40 % reduction in acquisition tim e and this without difference in the diagnostic performances of the reviewe rs.