Assessment of Collateral Circulation through Anterior Cerebral Artery Using the Transcranial Doppler in Patients with Acute Middle Cerebral Artery Infarction

Background: To investigate the optimal values of transcranial doppler (TCD) index in the evaluation of leptomeningeal collateral circulation (CC) in patients with middle cerebral artery (MCA) stenosis. Methods: Forty-one patients, with angiographically confirmed single stenosis or occlusion of the M1 segment of the MCA, were studied with TCD and brain MRI. Patients were divided into two groups according to the existence of CC though ipsilateral anterior cerebral artery on transfemoral cerebral angiography (TFCA). Mean flow velocities (mFV) of anterior and middle cerebral arteries (ACA, MCA) were analyzed. We then investigated the optimal values of TCD flow i ndex: 1) ipsilateral mFV ACA/MCA (AMVR), 2) ACA velocity ratio (ACAVR), 3) mFVACA. We then correlated TCD flow index with TFCA results. Results: TFCA revealed single moderate to severe M1 stenosis (n=35) and occlusion (n=6). Presence of CC was found in 11 (27%), absence of CC in 30 (73%). The mean of AMVR, ACAVR and mFVACA differed between the two groups: 1.76±0.69, 1.43±36, 86.27±31.73 cm/s in the presence of CC; 0.48±0.24, 1.21±0.39, 65.93±23.24 in the absence of CC. The optimal cutoff values for detection of CC were found at AMVR≥0.9, ACAVR≥1.30 and mFVACA≥80 cm/s. The combination of individual TCD indexes had improved the specificity and positive predicted value in the detection of CC. Conclusions: TCD enables detecting the existence of CC in patients with MCA stenoocclusion. These optimal values may provide a noninvasive method for evaluate the pathomechanism of stroke and prospect the prognosis of these patients. J Korean Neurol Assoc 23(2):165-171, 2005