American Board of Internal Medicine (ABIM) Certification Practice Exam

What imaging is recommended for a patient with a first unprovoked seizure and focal neurologic deficits?

1. An urgent noncontrast head CT

2. An MRI immediately

3. A routine head MRI

4. An EEG only

The correct answer is: An urgent noncontrast head CT

In the setting of a first unprovoked seizure accompanied by focal neurologic deficits, the recommended initial imaging is an urgent noncontrast head CT. This approach is taken because a head CT is quick and effective for ruling out acute intracranial pathology, such as hemorrhage or tumors, which could explain both the seizure and the focal deficits. Immediate imaging is essential in this context to identify any emergent causes that require urgent intervention. In contrast, while an MRI provides more detailed images of brain structures and is useful in the evaluation of the brain's anatomy, it is not the first-line imaging modality in an emergency setting due to the longer time it takes to perform and interpret. Routine MRI, while valuable for long-term evaluation of seizures, is not suitable in an acute situation where the possibility of life-threatening conditions needs to be ruled out swiftly. An EEG is also crucial in seizure evaluation, as it assesses the electrical activity of the brain and can contribute to diagnosis, but it does not provide information on structural abnormalities or acute lesions that might be causing the seizure. Therefore, the urgent noncontrast head CT is the most appropriate initial step in this clinical scenario.