Added Value of Contrast-Enhanced T1-Weighted and Diffusion-Weighted Sequences for Characterization of Incidental Findings on Whole Body Magnetic Resonance Imaging in Plasma-Cell Disorders.

BACKGROUND: Whole body magnetic resonance imaging (WBMRI) is currently recommended by guidelines for the assessment of myeloma. This will inevitably result in incidental findings. We aimed to assess the frequency of extraskeletal incidental findings and the added value of contrast-enhanced (CE) T1-weighted (T1-W) and diffusion-weighted (DWI) sequences for their characterization in a single WBMRI examination.

PATIENTS AND METHODS: We performed 1.5 T WBMRI in 100 patients (53 female; median age, 65 years) with plasma-cell disorders from January 2014 to July 2017. T2-weighted sequences were reviewed initially for incidental findings, followed by sequential review of T1-W, CE T1-W, and DWI sequences for lesion characterization. Descriptive statistics were undertaken.

RESULTS: A total of 348 incidental findings were detected in 97 (97%) of 100 patients; only 38 (10.9%) of 348 findings were indeterminate. T1-W sequences increased diagnostic confidence in the characterization of 12 (31.6%) of 38; CE T1-W sequences in the characterization of 16 (50%) of 32; and DWI increased diagnostic confidence in 21 (55.3%) of 38 compared to the T2-weighted sequence alone.

CONCLUSION: Incidental findings are common, but the majority are of no clinical consequence. No additional cancers were noted in our series. DWI and CE T1-W sequences increased diagnostic confidence in 50% of indeterminate findings and may reduce the need for further investigation.