Purpose: To study lumbar bone marrow by means of MR imaging before and after bone-marrow transplantation in lymphoma patients. Particular emphasis was paid to heterogeneity and to focal manifestations, i.e. appearances that could simulate tumor.
Material and methods: Twenty-two patients who were disease-free for a minimum of 30 months after transplantation were studied in 107 MR examinations. Two radiologists visually evaluated coronal T1-weighted and short inversion time inversion-recovery (STIR) images.
Results: T1-weighted images demonstrated a more heterogeneous marrow after transplantation than before it. Sharply defined focal low signal intensity areas appeared on this sequence in 5 (23%) of the 22 patients at between 21 and 60 weeks after transplantation. The mean age of these 5 patients was 48.4 years (range 42-54 years). The difference in age between these 5 patients and the remaining 17 patients, who had a mean age of 33.4 years (range 14-51 years), was statistically significant (p < 0.01, Student's t-test, 2-sided test).
Conclusion: Sharply defined focal low signal intensity areas may be seen on T1-weighted images of bone marrow in patients who are in complete remission after transplantation, particularly in those aged over 40-45 years.