MRI detection of radiographically occult fractures of the hip and pelvis in the elderly: Comparison of T2-weighted Dixon sequence with T1-weighted and STIR sequences

Purpose: To compare the diagnostic performance of T2-weighted Dixon, T1-weighted and Short- Tau Inversion Recovery (STIR) MR images for the detection of radiographically occult fractures (RDF) of the hip and pelvis in elderly patients after low-energy trauma. Materials and methods: A total of 22 patients older than 50 years with suspected ROF after low-energy trauma was prospectively included. There were 9 men and 13 women, with a mean age of 80.9 years +/- 12.5 (SD) (range: 52-100 years). T2-weighted Dixon, T1-weighted and STIR MR images were analyzed by 3 independent radiologists blinded to the clinical data and the results of other imaging examinations. Readers separately assessed each series of images for the presence of fractures on a per bone analysis. Diagnostic performance of each reader was compared for Dixon and non-Dixon sequences using contingency tables and McNemar test. Interobserver agreement was evaluated according to the Fleiss-Cuzick's kappa statistics. Results: The sensitivity of the Dixon sequence in the detection of ROF ranged from 90.9% (20/22; 95% CI: 70.8-98.9%) to 100% (22/22; 95% CI: 84.6-100%). The sensitivities of the non-Dixon sequences in the detection of ROF ranged from 95.5% (21/22; 95% CI: 77.2-99.9%) to 100% (22/22; 95% CI: 84.6-100%). For each reader, there were no statistical differences between combined Dixon and combined non-Dixon images for the detection of ROF (P = 0.12, 0.99 and 0.99). Interobserver agreement with T2-weighted Dixon water-only images was significantly lower than that with the STIR sequence (0.70-0.79 vs. 0.87-0.93). Conclusion: T2-weighted Dixon may be a second-rate alternative to T1-weighted and STIR sequences for the detection of ROF of the hip and pelvis in elderly patients. (C) 2018 Societe francaise de radiologie. Published by Elsevier Masson SAS. All rights reserved.