American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended imaging study for patients with optic neuritis?

1. CT scan of the brain

2. Electroencephalogram

3. MRI of the brain

4. PET scan

The correct answer is: MRI of the brain

In the evaluation of optic neuritis, MRI of the brain is the recommended imaging study because it offers detailed information about the optic nerves and brain structures. It is particularly useful for identifying any demyelinating lesions consistent with multiple sclerosis, which is a common underlying cause of optic neuritis. The MRI can help visualize abnormalities that may not be detected with other imaging modalities, providing insights into the presence and extent of demyelination. In contrast, a CT scan of the brain offers limited detail regarding soft tissue structures and is not as sensitive as MRI for detecting lesions associated with optic neuritis. An electroencephalogram is primarily used to assess electrical activity in the brain and is not relevant for diagnosing or evaluating optic neuritis. A PET scan, while useful in assessing metabolic processes and detecting malignancies, does not provide the necessary resolution or detail required for evaluating optic nerve inflammation or demyelination. Thus, MRI is the most effective and appropriate imaging technique for patients presenting with optic neuritis.