CONTRAST ENHANCEMENT AND QUANTITATIVE SIGNAL ANALYSIS IN MR-IMAGING OF MULTIPLE-MYELOMA - ASSESSMENT OF FOCAL AND DIFFUSE GROWTH-PATTERNS IN MARROW CORRELATED WITH BIOPSIES AND SURVIVAL RATES

OBJECTIVE. This study describes infiltration patterns of multiple myel oma in spinal MR imaging and correlates the findings with biopsies, su rvival rates, and signal intensity measurements in unenhanced and enha nced studies. MATERIALS AND METHODS. Fifty-three patients with multipl e myeloma and 53 age-matched controls underwent MR imaging of the spin e. Twenty-nine patients underwent sagittal T1-weighted spin-echo enhan ced imaging and all patients underwent sagittal T1-weighted spin-echo unenhanced and opposed-phase gradient-recalled echo images, and signal intensity measurements were taken. MR imaging was correlated to marro w specimens (n = 40) and a clinical staging system. The probability of survival was also calculated. Finally, we performed qualitative visua l evaluation (infiltration pattern, degree of tumor involvement) and a quantitative evaluation (marrow signal intensity ratios, contrast, en hancement). RESULTS. Five infiltration patterns were found: normal-app earing marrow with low-grade interstitial infiltration (n = 5), focal (n = 18), diffuse (n = 12), focal and diffuse (n = 13), and salt-and-p epper (n = 5). Infiltration pattern correlated with clinical staging; all patients with normal-appearing and salt-and-pepper patterns were c linically stage I. Diffuse marrow infiltration was assessed by marrow ratios: low-grade infiltration, greater than 2.0; intermediate, 1.0-2. 0; high-grade, less than 1.0. Contrast enhancement with a signal inten sity increase greater than 40% indicated diffuse infiltration. In the control group, all of whom had no marrow disease,. enhancement varied (mean +/- SD, 16% +/- 8.9%) but did not exceed 40%. Marrow involvement on MR images correlated significantly with clinical staging and survi val (p less than or equal to .001). CONCLUSION. MR imaging with oppose d gradient-recalled echo sequences and contrast enhancement provided d ata that allowed us to classify infiltration patterns and to quantify diffuse marrow involvement in multiple myeloma, both of which correlat ed tb clinical staging and biopsy. Also, the MR data was of prognostic value. Therefore, like laboratory parameters, biopsies, and radiograp hs, MR imaging can be a supporting pillar in staging and planning trea tment of patients with multiple myeloma.