Evaluation of cerebrovascular reactivity by ultrasonography in type 2 diabetic patients with hypertension

142 subjects (103 patients with type 2 diabetes mellitus and/or primary hypertension, and 39 healthy controls). Excluded if stenosis rate of unilateral internal carotid artery or common carotid artery ≥ 70%.

Transcranial color-coded duplex sonography with breath holding test (hypercapnia)

Healthy controls and comparison between disease groups (DM alone, hypertension alone, DM with hypertension)

Mean blood flow velocity, blood flow diameter, and middle cerebral artery (MCA) blood flow volume, and their increase rates before and after breath holdingsurrogate