IMAGING IN MULTIPLE-MYELOMA

Multiple myeloma (MM) is characterized by a proliferation of plasma ce lls responsible for osteolytic lesions. Imaging studies are performed in MM to establish diagnosis and prognosis, and may also be used to ju dge the efficacy of treatment and to detect complications. To establis h the diagnosis. - Conventional radiography demonstrates, at the time of diagnosis, characteristic features in 80 % of cases. These lytic le sions involve more often the sites of red marrow. More rarely the only abnormal finding is diffuse osteopenia. Tomodensitometry and, above a ll, magnetic resonance imaging (MRI), which is a reference method for bone marrow disorders, can be useful for diagnosis in some difficult c ases. But the lesions observed, hyposignals on spin echo T1 sequences and hyposignals on T2 - weighted gradient echo, are not specific and u sually do not allow to distinguish MM from osteolytic metastasis or ot her bone marrow disorders. To determine extent of disease and to evalu ate prognosis. - According to Durie and Salmon, the extension of bone lesions at diagnosis is strongly correlated with the myelomatous measu red cellular mass and with survival of patients. But this relation is denied by some authors who have noted that the shortest survival was s een in patients with normal X-rays. To judge the efficacy of treatment . - Improvement of the radiological abnormalities is observed in nearl y 30 % of patients responding to a conventional chemotherapy and appea rs to be an adverse pronostic sign. A good correlation between MRI and the biological response to treatment has also been reported. To recog nize complications of disease. - Conventional radiography is also very important in diagnosis of complications like fractures or vertebral c ompression. Lastly, MRI is the investigation of first choice in the ev aluation of patients with suspected spinal cord compression.