From the Guidelines
To distinguish between intracranial atherosclerosis and vasculitis, a comprehensive approach using clinical presentation, laboratory tests, and imaging studies, particularly contrast-enhanced MRI vessel wall imaging, is necessary. This approach is supported by recent studies, such as the one published in the Journal of the American College of Radiology in 2021 1, which highlights the utility of MRI in evaluating CNS vasculitis due to its superior soft-tissue characteristics and ability to identify inflammatory changes in the vessel wall.
Key differences in clinical presentation include:
- Intracranial atherosclerosis typically presenting in older patients with vascular risk factors like hypertension, diabetes, and hyperlipidemia
- Vasculitis often affecting younger patients with systemic inflammatory symptoms such as fever, weight loss, and rash
Laboratory testing for vasculitis should include:
- Inflammatory markers (ESR, CRP)
- Autoimmune panels (ANA, ANCA, rheumatoid factor)
- Specific tests like HIV or hepatitis screening when indicated
Imaging findings differ significantly:
- Atherosclerosis shows focal stenosis at branch points with calcifications on CT and eccentric plaque on vessel walls
- Vasculitis demonstrates segmental narrowing, beading appearance, and vessel wall enhancement on contrast MRI, as noted in a study published in the Journal of the American College of Radiology in 2021 1
Cerebrospinal fluid analysis may reveal inflammation in vasculitis cases but is typically normal in atherosclerosis. Digital subtraction angiography remains valuable for detailed vascular assessment, showing smooth tapering in atherosclerosis versus irregular narrowing in vasculitis. When diagnosis remains unclear, brain biopsy may be necessary for definitive vasculitis diagnosis, though it's invasive and reserved for cases where treatment decisions depend on histological confirmation, as discussed in a scientific statement from the American Heart Association Stroke Council and the Council on Cardiovascular Disease in the Young in 2008 1.
From the Research
Distinguishing between Intracranial Atherosclerosis and Vasculitis
To distinguish between intracranial atherosclerosis and vasculitis, several factors and imaging techniques can be considered:
- Intracranial atherosclerosis is a progressive pathological process that causes stenosis and cerebral hypoperfusion, leading to stroke occurrence and recurrence 2.
- Imaging techniques such as angiography, high-resolution magnetic resonance imaging (HRMRI), and vessel wall MR imaging can help diagnose and characterize intracranial atherosclerotic disease 3, 4.
- HRMRI can directly visualize the vessel wall pathology and identify plaque components, such as intraplaque hemorrhage, fibrous cap, and lipid core 5.
- Advanced radiological techniques, including computed tomography angiography (CTA), magnetic resonance angiography (MRA), high-resolution MRA, and computational fluid dynamics, can reveal underlying pathophysiological mechanisms and detect non-stenosing intracranial atherosclerosis 6.
- The characterization of intracranial atherosclerotic stenosis using HRMRI can inform the design of future multicenter studies to determine the prevalence and prognosis of intracranial atherosclerotic plaque components 5.
Key Imaging Features
Some key imaging features that can help distinguish between intracranial atherosclerosis and vasculitis include:
- Stenosis on luminal imaging, which is a common feature of intracranial atherosclerotic disease 6.
- Plaque components, such as intraplaque hemorrhage, fibrous cap, and lipid core, which can be identified using HRMRI 5.
- Vessel wall enhancement and thickening, which can be detected using vessel wall MR imaging 3.
- Non-stenosing intracranial atherosclerosis, which can be detected using advanced radiological techniques such as high-resolution MRA and computational fluid dynamics 6.