Kasuya H, Shimizu T, Nakaya K, Sasahara A, Hori T, Takakura K
Department of Neurosurgery, Tokyo Women's Medical College, Japan.
Neurosurgery. 1999 Jul;45(1):89-93; discussion 93-4. doi: 10.1097/00006123-199907000-00021.
The angle of arteries at bifurcations, as well as the blood flow, are factors of hemodynamic stress on the apical region, where aneurysms often develop. Using images obtained with three-dimensional computed tomographic angiography, we sought to determine the angles between the A1 and A2 segments of the anterior cerebral artery of the anterior communicating artery (ACoA) complex associated with aneurysms. These angles cannot be detected by conventional cerebral angiography.
The course of the anterior cerebral artery was studied using three-dimensional computed tomographic angiography in 42 consecutive patients with ACoA aneurysms. Twenty-one other subjects, randomly chosen from patients without aneurysms, served as controls. Bilateral A1-A2 angles of the contrast-opacified anterior cerebral artery were measured by three-dimensional computed tomographic angiography in patients with normoplastic A1 segments, and the relationship between the angle and the association of aneurysms was analyzed using cerebral angiography.
Of the 42 patients with ACoA aneurysms, 19 patients showed hypo- or aplastic A1 segments, as did only 2 of the 21 patients without ACoA aneurysms. The average A1-A2 angle was determined to be 116+/-24 degrees (mean+/-standard deviation) in 18 patients having ACoA complexes with normoplastic A1 segments with aneurysms; 17 patients without aneurysms had A1-A2 angles measuring 143+/-14 degrees (P < 0.0001). The A1-A2 angle associated with ACoA aneurysms was 103+/-20 degrees, which was much smaller than that of the non-aneurysm side in the former group (128+/-20 degrees) (P = 0.0036).
ACoA aneurysms are associated with the smaller A1-A2 angle junction of the ACoA complex, where higher hemodynamic stress may occur in patients with normoplastic A1 segments.
动脉分叉处的角度以及血流情况，是对顶端区域产生血流动力学应力的因素，而动脉瘤常在此区域发生。我们利用三维计算机断层血管造影获取的图像，试图确定与动脉瘤相关的前交通动脉（ACoA）复合体大脑前动脉A1段和A2段之间的角度。这些角度无法通过传统脑血管造影检测到。
对42例连续的ACoA动脉瘤患者使用三维计算机断层血管造影研究大脑前动脉的走行。从无动脉瘤患者中随机选取另外21名受试者作为对照。对具有正常形态A1段的患者，通过三维计算机断层血管造影测量造影剂充盈的大脑前动脉的双侧A1 - A2角度，并使用脑血管造影分析该角度与动脉瘤关联之间的关系。
42例ACoA动脉瘤患者中，19例显示A1段发育不全或未发育，21例无ACoA动脉瘤的患者中只有2例如此。18例具有正常形态A1段且伴有动脉瘤的ACoA复合体患者的平均A1 - A₂角度确定为116±24度（平均值±标准差）；17例无动脉瘤的患者A1 - A₂角度为143±14度（P < 0.0001）。与ACoA动脉瘤相关的A1 - A₂角度为103±20度，远小于前一组中无动脉瘤一侧的角度（128±20度）（P = 0.0036）。
ACoA动脉瘤与ACoA复合体较小的A1 - A₂角度交界处相关，在具有正常形态A1段的患者中，此处可能会出现更高的血流动力学应力。
