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

Abstract

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. 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). 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). 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.