E2386. The Great Imitator: Background, Pearls and Pitfalls to Radiologic Interpretation of the Treated Brain
  1. John Biren-Fetz; University of Illinois
  2. Joseph Wilson; University of Illinois
  3. Raj Shah; University of Illinois
  4. Edward Michals; University of Illinois
To provide a background of the relevant clinical presentations in which chemoradiation sequelae commonly occur. Diagnosis can be challenging as not all patients present with the same tumor grade, size, or clinical presentation, which affects tumor appearance on initial imaging as well as response to subsequent treatment. Unfortunately, conventional MRI, which is the main imaging technique used to differentiate treatment effect from tumor recurrence or progression is unreliable. This necessitates the use of advanced imaging modalities such as positron emission tomography, MR perfusion imaging, and MR spectroscopy. Additional goals are to familiarize the reader with common clinical presentations and treatment modalities, categories (i.e. progression vs pseudoprogression), advanced imaging modalities, and possible pitfalls.

Educational Goals / Teaching Points
The purpose of this is exhibit is to review and provide background of the common clinical scenarios of intracranial chemoradiation use. Additional goals of the exhibit are to familiarize the reader with the types of radiation treatment (i.e. whole brain, stereotactic, or chemotherapy) and common imaging modalities used for treatment assessment and monitoring. The exhibit will also discuss treatment effect (i.e. pseudoprogression vs. treatment occurrence), tumor genetics as well as common pitfalls and appropriate follow-up.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This presentation will concentrate on common pathologies that can present in the day-to-day workload of a practicing radiologist. The main topics to be discussed will be a brief overview of common clinical scenarios and chemoradiation sequelae. Additional topics covered will include identification of easily missed or misdiagnosed lesions and the common imaging features to help guide the diagnosis using a case-based approach. Common pitfalls in imaging interpretation and appropriate follow-up examinations will be explored.

Familiarity with the relevant clinical scenarios, clinical history, and frequently used imaging modalities are essential to radiologic interpretation and help guide proper diagnosis as well as clinical management.