Branch occlusive disease: clinical and magnetic resonance angiography findings

We evaluated the clinicoradiologic characteristics of patients with branch occlusive disease (BOD)-type intracranial atherosclerotic stroke (ICAS) compared with those of patients with non-BOD-type ICAS or with small artery disease (SAD).

We analyzed 201 consecutive patients with acute infarcts within the middle cerebral artery (MCA) distribution but no demonstrable carotid or cardiac embolism sources. According to the diffusion-weighted imaging (DWI) distribution and the presence of ipsilateral MCA stenosis, of any degree, on magnetic resonance angiography (3-T MRI), we divided patients into 3 groups: 1) BOD: subcortical infarcts with MCA stenosis (n = 46); 2) non-BOD: infarcts beyond the subcortical area with MCA stenosis (n = 52); and 3) SAD (n = 103). We compared risk factors, degree of stenoses and distribution, and radiologic features of microangiopathy (leukoaraiosis and cerebral microbleeds) among the groups.

Risk factor profiles were similar among the groups, except that hypertension and current smoking were more prevalent in the non-BOD than in the BOD group (p = 0.032 and 0.045). The relevant MCA had more severe and focal stenosis in the non-BOD than in the BOD group (stenosis of ≥70%; 76.9% vs 28.3%; p < 0.001), but the degree of nonrelevant stenosis was similar across the groups. Although clinical features, DWI lesion patterns, and microangiopathy findings were similar between the BOD and SAD groups, nonrelevant stenosis was more prevalent in the BOD than in the SAD group (p < 0.01).

BOD is prevalent (47% of ICAS) and shares common characteristics with non-BOD-type ICAS, although its clinicoradiologic features may resemble those of SAD. The morphologic characteristics of stenosis and risk factors may associate with a stroke phenotype in patients with ICAS.