American Board of Internal Medicine (ABIM) Certification Practice Exam

What definitive diagnostic procedure is recommended for primary angiitis of the central nervous system?

1. Plain X-ray

2. Intracerebral angiography with brain biopsy

3. MRI with contrast

4. Ultrasound of the brain

The correct answer is: Intracerebral angiography with brain biopsy

Primary angiitis of the central nervous system (PACNS) is a rare and potentially devastating condition characterized by the inflammation of blood vessels in the brain. Making an accurate diagnosis of PACNS is critical, as it influences treatment decisions and the management of the condition. The definitive diagnostic procedure for PACNS involves intracerebral angiography in conjunction with brain biopsy. Intracerebral angiography is essential as it helps visualize the abnormalities in the blood vessels, which can provide crucial evidence of the underlying vascular inflammation. A brain biopsy is necessary to confirm the diagnosis histologically, revealing the presence of vasculitis within the affected cerebral tissue. While imaging techniques such as MRI with contrast can show changes consistent with PACNS, they cannot definitively diagnose the condition. Plain X-rays and ultrasounds of the brain have limited ability to visualize central nervous system vasculitis and are not recommended for diagnosing PACNS. Therefore, the combination of intracerebral angiography and brain biopsy constitutes the gold standard for diagnosing primary angiitis of the central nervous system.