Collateral Compensative Capacity in Patients with Serious Stenosis or Occlusion of Middle Cerebral Artery Stem Assessed by Transcranial Doppler

【Objective】To evaluate the collateral compensative patterns in patients with serious stenosis or occlusion of middle cerebral artery stem.【Methods】Forty five patients with serious stenosis or occlusion of middle cerebral artery stem determined by digital subtraction or MR angiography were selected to serve as patient group and forty five patients without disease of middle cerebral artery stem were selected to serve as controls.All patients were measured by transcranial Doppler.【Results】In the patient group,transcranial Doppler showed blood flow velocity compensative acceleration of the lesion side anterior cerebral artery.The blood velocity ratios of anterior cerebral artery for the patient group(1.48±0.21) was significantly higher than ratios for controls(1.02±0.13).There was a significant difference between the two groups(t=3.582,P0.001).Four patients(9%)showed blood flow velocity compensative acceleration of the lesion side posterior cerebral artery.The blood flow appearance of other collateral circulation pathway was not found in the patient group.【Conclusion】The opening of leptomeningeal anastomoses vessel is important way of collateral circulation in cases of serious stenosis or occlusion of middle cerebral artery stem.Blood flow velocity compensative acceleration of the lesion side anterior cerebral artery and posterior cerebral artery could be used in the diagnosis of middle cerebral artery occlusion and may also provide objective index about the changes in collateral blood flow from the anterior and posterior cerebral artery territory into the middle cerebral artery territory.