Female pelvic bone marrow: serial MR imaging before, during, and after radiation therapy.

Abstract

To study early changes in irradiated pelvic and adjacent nonirradiated bone marrow with T1-weighted magnetic resonance (MR) and short inversion time inversion-recovery (STIR) imaging. The bone marrow of 31 women with advanced cervical carcinoma was studied in 161 MR examinations before, during, and 7 weeks after radiation therapy. Two radiologists visually evaluated the marrow signal intensity (MSI) on T1-weighted and STIR images. Changes in irradiated and adjacent nonirradiated marrow were shown on T1-weighted images in 31 (100%) and 18 (58%) of the 31 patients, respectively. MSI changes on images were observed as early as 8 days after the start of radiation therapy and occurred more frequently in irradiated than in adjacent nonirradiated marrow. In the irradiated regions, a complete fatty marrow was seen on T1-weighted images obtained 6-8 weeks after the start of radiation therapy in 28 (90%) of the 31 patients. T1-weighted and STIR images obtained during and soon after radiation therapy complement each other in showing changes in bone marrow.