MRI is highly sensitive for detecting multiple myeloma in bone marrow, showing focal lesions, diffuse marrow infiltration, plasmacytomas and spinal cord compression. Whole‑body MRI or spine/pelvis MR with contrast and diffusion‑weighted sequences can find lesions earlier than X‑rays. MRI supports staging and treatment planning but cannot, by itself, confirm diagnosis; bone marrow biopsy and blood/urine tests are required.

Whole‑body MRI is the most sensitive test for detecting marrow involvement and early focal lesions in multiple myeloma. Low‑dose whole‑body CT is superior for identifying cortical bone destruction. FDG PET/CT is useful for detecting metabolically active and extramedullary disease and for treatment response assessment. Choice depends on the clinical question, availability and staging needs; modalities are often combined.

The 2‑20‑2 rule is a quick mnemonic to flag active multiple myelom

Radiographs classically show multiple well‑defined "punched‑out" lytic lesions throughout the skull, spine, pelvis and long bones, with diffuse osteopenia and cortical thinning. Vertebral compression fractures and endosteal scalloping are common. Lesions typically lack reactive sclerosis. Plain radiograph bone survey often detects these patterns, while CT and MRI are more sensitive for marrow infiltration and occult lesions.

Multiple myeloma is confirmed by demonstration of clonal plasma-cell proliferation on bone marrow biopsy (≥10% clonal plasma cells) or biopsy-proven plasmacytoma, together with myeloma-defining organ damage (CRAB: hypercalcemia, renal impairment, anemia, bone lesions) or biomarkers (≥60% clonal plasma cells, involved/uninvolved free light chain ratio ≥100, or >1 focal MRI lesion). Supporting tests include serum/urine electrophoresis, immunofixation, and imaging.

Yes. MRI is excellent for visualizing bone marrow because it detects differences in fat and water content, allowing assessment of normal marrow, red versus yellow marrow, and abnormalities such as edema, infection, marrow infiltration (tumor, metastases), or marrow‑replacing disorders. Cortical bone itself is poorly visualized on MRI, so fractures or calcified changes are better seen with CT or X‑ray; contrast can aid characterization.