Diagnostic value of whole-body ultra-low dose computed tomography in comparison with spinal magnetic resonance imaging in the assessment of disease in multiple myeloma

This study compared the diagnostic value of Whole-Body Ultra Low-Dose computed tomography (WBULDCT) with that of Spinal Magnetic Resonance Imaging (SMRI) in identification of spinal bone marrow involvement in patients with Multiple Myeloma (MM). Thirty-five patients with histologically proven MM underwent WBULDCT and dedicated SMRI. Unenhanced WBULDCT was performed on a 256-slice scanner, with 120 kV and 40 mAs. SMRI was performed on a 1·5T magnet, with T1-turbo spin echo and T2-short tau inversion recovery sequences on sagittal plane. WBULDCT was compared with SMRI in terms of lesion detection, pattern and bone marrow involvement. The overall concordance between WBULDCT and SMRI in lesion detection was 76·7%, detecting (25/35) or excluding (8/35) involvement of the axial skeleton, while in 2/35 patients WBULDCT and SMRI were discordant in terms of axial skeleton involvement. The concordance in spinal distribution of lesions was 61·6% on cervical, 71·5% on dorsal, 86·4% on lumbar and 94·4% on sacral, while for the pattern of disease, it was 56·1% for the focal and 88·7% for the combined pattern. Cohen's kappa index was 0·85 (P < 0·001) assessing an excellent agreement. WBULDCT represents a useful diagnostic tool in the detection of spinal involvement of MM patients, offering detailed information about extra-axial involvement, which could be potentially missed with dedicated SMRI.