Tanaka H, Fujita N, Enoki T, Matsumoto K, Watanabe Y, Murase K, Nakamura H
Department of Radiology, Osaka University Medical School, Osaka, Japan.
AJNR Am J Neuroradiol. 2006 Sep;27(8):1770-5.
Volume flow rates in the feeding arteries of the brain are measured to evaluate blood flow dynamics in vascular disease. Although these flow values are thought to be effected by anatomic variations in the circle of Willis, few reports have described the effect. This study reports on the relationship between variations in the circle of Willis and volume flow rates in the bilateral internal carotid and basilar arteries of normal volunteers.
We prospectively examined 125 healthy volunteers by MR imaging. Variations in the circle of Willis were classified as "textbook" type, hypoplasia of the precommunicating segment of the anterior cerebral artery (A1), hypoplasia of the precommunicating segment of the posterior cerebral artery (P1), or "other." Volume flow rates were measured by 2D cine phase-contrast MR imaging. Lumen boundaries and volume flow rates were semiautomatically determined by pulsatility-based segmentation.
Of the 117 subjects (61 men, 56 women; mean age, 23.6 years) considered suitable for flow measurement, 105 showed textbook type, and 6 each showed A1 hypoplasia and P1 hypoplasia. Total flow rates for the 3 variations were 781 +/- 151 mL/min (mean +/- SD), 744 +/- 119, and 763 +/- 129, respectively. Relative contributions by flow rates of the internal carotid arteries and the basilar artery for the 3 variations were 39.8%:38.9%:21.3%, 31.8%:49.1%:19.0%, and 46.6%:41.6%:11.7%, respectively, showing statistically significant differences.
Variations in the circle of Willis correlate significantly with relative contributions by the flow rates of the bilateral internal carotid and basilar arteries.
测量脑供血动脉的血流速度以评估血管疾病中的血流动力学。尽管这些血流值被认为受Willis环解剖变异的影响，但很少有报告描述这种影响。本研究报告了Willis环变异与正常志愿者双侧颈内动脉和基底动脉血流速度之间的关系。
我们对125名健康志愿者进行了前瞻性磁共振成像检查。Willis环的变异被分类为“教科书”型、大脑前动脉（A1）交通前段发育不全、大脑后动脉（P1）交通前段发育不全或“其他”。通过二维电影相位对比磁共振成像测量血流速度。通过基于搏动性的分割半自动确定管腔边界和血流速度。
在117名被认为适合进行血流测量的受试者（61名男性，56名女性；平均年龄23.6岁）中，105名显示为“教科书”型，各有6名显示A1发育不全和P1发育不全。这三种变异的总血流速度分别为781±151 mL/分钟（平均值±标准差）、744±119和763±129。这三种变异中颈内动脉和基底动脉血流速度的相对贡献分别为39.8%:38.9%:21.3%、31.8%:49.1%:19.0%和46.6%:41.6%:11.7%，显示出统计学上的显著差异。
Willis环变异与双侧颈内动脉和基底动脉血流速度的相对贡献显著相关。
