Brain parenchymal infection in bone marrow transplantation patients: CT and MR findings

The purpose of this study was to assess the MR and CT appearance of brain infection after bone marrow transplantation and to correlate the appearances with laboratory and pathologic findings.

We retrospectively reviewed the records of seven bone marrow transplant recipients with radiologic evidence of brain infection.

Forty-one lesions were detected in seven patients with proved infectious foci outside the brain before brain infection was suspected clinically. Six patients had low total WBC or lymphocyte counts and one patient had normal total WBC and lymphocyte counts. Most lesions in patients with low total WBC or lymphocyte counts showed no appreciable edema or contrast enhancement. However, all lesions detected in the patient with normal total WBC and lymphocyte counts showed marked vasogenic edema and ring enhancement.

Brain infection in bone marrow transplant recipients during immunosuppression exhibited MR characteristics different from those typically seen in immunocompetent patients. This appearance may be related to a diminished immunologic/inflammatory response.