Prognostic Significance of Magnetic Resonance Imaging (MRI) of Bone Marrow in Previously Untreated Patients with Multiple Myeloma.

Purpose: To determine the prognostic value of spinal bone MRI in symptomatic patients with multiple myeloma requiring treatment.

Materials and methods: Between January 1990 and Decmber 2001, 142 patients with symptomatic multiple myeloma (MM) underwent MRI of the spine before initiation of treatment. All patients received primary treatment based on high dose pulse dexamethasone (D) such as VAD or Melphalan + D. High-dose therapy with autologous stem cell transplantation was administered to 61 patients. MRI patterns of involvement were correlated with known prognostic variables of myeloma (including the International Staging System (ISS)), with response to treatment and with survival.

Results: Focal marrow lesions with intervening normal marrow were identified in 50% of patients, diffuse marrow replacement in 28%, a variegated pattern consisting of innumerable small foci of marrow replacement on a background of normal marrow in 14% and normal MRI pattern in 8% of patients. When patients with diffuse pattern were compared to patients with other MRI patterns, they had features of more advanced disease such as higher ISS, anemia, hypercalcemia, extensive bone marrow plasmacytosis, elevated serum LDH and impaired renal function. Patients and disease features were similar among patients with normal, focal or variegated MRI patterns. The frequency of response to primary treatment was similar among patients with different MRI patterns. Median survival was 24 months for patients with a diffuse pattern, 51 months for those with a focal pattern, 52 months for variegated and 56 months for patients with normal pattern (p=0.001). The presence or absence of diffuse MRI pattern separated the patients with ISS 1 and 2 into two subgroups with significantly different survival times of 28 months and 61 months respectively (p=0.01). Among patients with ISS 3, those with a diffuse pattern had a median survival of 18 months, whereas the remaining patients survived for a median of 30 months (p=0.5). Furthermore, a diffuse pattern predicted an inferior outcome both in patients who did or did not receive high dose therapy with autologous stem cell transplantation.

Conclusion: MRI of the spine before treatment provides prognostic information for symptomatic patients with myeloma, especially for those with ISS 1 or 2. Diffuse marrow replacement on MRI of the spine identifies patients with advanced MM who have a poor prognosis. Such patients are candidates for innovative treatments.