Vessel and Vessel Wall Imaging.

Angiography is a useful, important, common imaging method, with digital subtraction angiography (DSA) remaining the gold standard for luminal imaging. Computed tomography angiography (CTA) is minimally invasive and quite accurate in the evaluation of stenosis. Magnetic resonance angiography (MRA) is a good screening tool with the least invasiveness. Angiography mostly represents intracranial artery disease as luminal stenosis, which is often not sufficient to evaluate intracranial vascular pathology. The modalities provide indirect information about vascular pathology because luminal change, such as stenosis, results from the changes of vessel walls. Vessel wall imaging using high-resolution magnetic resonance imaging (HR-MRI) has been recently introduced for direct evaluation of vessel walls beyond just luminal information such as the severity of stenosis. HR-MRI for vessel walls can present the characteristic radiological findings for each intracranial artery disease such as atherosclerosis, dissection, moyamoya disease, and vasculitis. The radiological features are useful to differentiate among intracranial artery disease. This chapter discusses the role and radiological features of angiography and HR-MRI for vessel walls.