CAMRT Radiography Practice Exam

How does a chronic subdural hematoma appear on a CT scan?

1. Hypodense lesion

2. Isodense lesion

3. Heterogeneous lesion

4. Hyperdense lesion

The correct answer is: Isodense lesion

A chronic subdural hematoma typically appears as an isodense lesion on a CT scan. This is due to the fact that, over time, the blood within the hematoma undergoes a process of resorption and can eventually attain a density similar to that of the surrounding brain tissue. As a result, these lesions may not be readily apparent on a standard CT scan, especially if the scan is performed during the later stages of the hematoma's evolution. The transition from hyperdense (seen in acute hematomas due to the presence of fresh blood) to isodense occurs as the blood breaks down and the hematoma becomes more fluid-like in nature. This makes it challenging to detect chronic subdural hematomas, emphasizing the importance of clinical correlation and, if necessary, additional imaging techniques for proper diagnosis.