Neuroimaging of therapy-associated brain tissue abnormalities

Purpose of review This study summarizes recent advances in neuroimaging of therapy-related brain tissue abnormalities. Recent findings Pseudoprogression constitutes a typical posttherapeutic phenomenon in patients with glioblastoma treated with radiochemotherapy with temozolomide. Advanced MRI techniques, such as diffusion MRI and perfusion MRI, can be helpful to distinguish it from true tumor progression. In clinical trials on amyloidmodifying therapies in Alzheimer's disease patients, previously unknown, characteristic nonhemorrhagic and hemorrhagic amyloid-related imaging abnormalities have been observed. Awareness of this phenomenon is essential for therapy monitoring. Posterior reversible encephalopathy syndrome and reversible cerebral vasoconstriction syndrome can both occur as a complication of a variety of systemic drug therapies and present with a wide spectrum of clinical and imaging findings. The pathomechanisms underlying these different therapy-related brain tissue changes are only poorly understood. Summary Neuroimaging, including advanced MRI techniques, plays a key role in the identification and monitoring of therapy-associated brain tissue abnormalities. However, future imaging studies should focus on the pathomechanism underlying these phenomena.