To assess the distribution of bone lesions in patients with prostate cancer (PCa) and those with multiple myeloma (MM) using whole-body magnetic resonance imaging (MRI); and to assess the added value of four anatomical regions located outside the thoraco-lumbo-pelvic area to detect the presence of bone lesions in a patient-based perspective.

Fifty patients (50 men; mean age, 67±10 [SD] years; range, 59–87 years) with PCa and forty-seven patients (27 women, 20 men; mean age, 62.5±9 [SD] years; range, 47–90 years) with MM were included. Three radiologists assessed bone involvement in seven anatomical areas reading all MRI sequences.

In patients with PCa, there was a cranio-caudal increasing prevalence of metastases (22% [11/50] in the humeri and cervical spine to 60% [30/50] in the pelvis). When the thoraco-lumbo-pelvic region was not involved, the prevalence of involvement of the cervical spine, proximal humeri, ribs, or proximal femurs was 0% in patients with PCa and≥4% (except for the cervical spine, 0%) in those with MM.

In patients with PCa, there is a cranio-caudal positive increment in the prevalences of metastases and covering the thoraco-lumbo-pelvic area is sufficient to determine the metastatic status of a patient with PCa. In patients with MM, there is added value of screening all regions, except the cervical spine, to detect additional lesions.