Diagnosis of Intracranial Stenosis

The diagnosis of intracranial stenosis has improved with the advent and availability of non-invasive vascular imaging tests. Vascular imaging modalities to consider include transcranial Doppler, magnetic resonance and computed tomographic angiography. While these have strengths and weaknesses, they provide anatomic information. Physiologic and/or hemodynamic data can be gleaned from perfusion imaging, vasomotor reactivity testing, positron emission tomography, and quantitative magnetic resonance angiography. These latter tests may be particularly useful in stratifying stroke risk in individuals with intracranial stenosis. While most cases are due to atherosclerotic disease, the astute clinician still needs to consider other etiologies including vasoconstriction, vasculitis, and dissection before embarking on treatment decisions.