Short tau inversion recovery and three-point Dixon water-fat separation sequences in acute traumatic bone fractures at open 0.35 tesia MRI

Objective: Fat suppression can be used to improve the diagnostic confidence in traumatic bone fractures of the extremities. We compared a three-point Dixon "sandwich" water-fat separation (WFS) sequence, resulting in a water-only and a fat-only image set after one excitation, with the STIR sequence on an open 0.35 T superconductive MR system. Design and patients: T1-weighted, STIR (2000/40 [TR/TE]), and WFS (2000/36 [TR/TE]) MR images were prospectively obtained in 27 patients with 40 radiologically diagnosed fractures immediately after first-line treatment. Signal-to-noise (S/N) ratio, contrast-to-noise (C/N) ratio, and bone marrow edema volumes were measured together with qualitative parameters (four-point scale). Results: WFS was significantly superior to STIR in all quantitative parameters (better S/N ratio, P<0.001; better C/N ratio, P<0.001; larger marrow edema, P<0.023; Wilcoxon signed rank test). Visibility of bone marrow edema, visibility of fracture line, and preservation of anatomical details were better with the WFS sequence (P<0.001, P<0.001, P<0.001, respectively; ANOVA). Fat saturation was rated more homogeneous, however, with the STIR sequence (not significant; P<0.101). Conclusion: On the basis of qualitative and quantitative assessments, the three-point Dixon "sandwich" water-fat separation sequence was consistently superior to the STIR sequence in the delineation of traumatic fractures.