Objectives:To compare the relative conspicuity of bone metastases on short-tau inversion recovery (STIR) and diffusion-weighted MRI (DWI) whole body MR sequences for breast, prostate and myeloma malignancies.
Methods: 44 whole body MRI scans were reviewed retrospectively (coronal T1 weighted, STIR and DWI with b = 800). On each scan, up to four of the largest bone lesions were identified on T1 weighting, and the region of interest signal intensity was measured on STIR and DWI, as well as the background signal intensity. The mean lesion signal to background ratio was calculated for each patient and then for each malignancy group.
Results: In prostate cancer patients, DWI signal/background ratio was greater than that of STIR in 22 out of 24 patients (mean DWI lesion/background ratio 3.91, mean STIR lesion/background ratio 2.31; p = 0.0001). In multiple myeloma, DWI ratio was higher in 6/7 patients (DWI group mean ratio 7.59, STIR group mean ratio 3.7; p = 0.0366). In 13 breast cancer patients, mean STIR and DWI signal/background were similar (DWI group mean ratio 4.13, group mean STIR ratio 4.26; p = 0.8587).
Conclusion: Bone lesion conspicuity measured by lesion/background signal intensity was higher on DWI b800 than on STIR in patients with prostate cancer and multiple myeloma. DWI should be used in whole body MR oncology protocols in these conditions to maximise lesion detection.
Pearce T, Philip S, Brown J, Koh DM, Burn PR. Are you the author?
Department of Diagnostic Imaging, Musgrove Park Hospital, Taunton TA1 5DA, UK.
Reference: Br J Radiol. 2012 Mar 28. Epub ahead of print.
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