Central Nervous System Effects of Therapy in Patients Treated for Hematological Malignancies

Patients treated for hematological malignancies may develop central nervous system (CNS) complications at some point in the course of the disease. Some complications are caused by the underlying disease itself, while others are treatment-related. The latter include possible toxic side effects of irradiation and/or chemotherapy, infections caused by immunosuppression, thrombocytopenia, nutritional and metabolic stresses, and graft-versus-host disease (GVHD). As a result, CNS effects of therapy may be infectious, vascular, toxic, metabolic, or tumoral. Familiarity with these complications allows early recognition of most problems, and differentiation between CNS complications from the original disease and complications from the treatment. This is of clinical importance as — depending on the cause — patients may require additional or reinforced treatment, or withdrawal from therapy. This chapter presents a range of typical CT and MR imaging appearances of CNS therapeutic abnormalities seen in patients treated for hematological malignancies. Neurological imaging, in combination with electrophysiological studies as well as blood and cerebrospinal fluid investigations, may be helpful for diagnosing most of these complications, as well as in differentiating between the manifestations of the underlying disease and complications of the treatment. The main issues to keep in mind are that certain complications are most likely due to multiple underlying diseases, and that more than one complication can coexist.