CT Findings Of Ruptured Intracranial Aneurysms With Subarachnoid Hemorrhage

Objective:To investigate imaging MSCT features of the ruptured intracranial aneurysms preliminarily.Methods:We retrospective evaluated MSCT images of 115 patients with spontaneous subarachnoid hemorrhage obtained between July 2005 and November 2009, which including male 46, female 69, age range 24-79 years,56.02±10.8 years. All patients which underwent computed tomography angiography (CTA) had been confirmed of ruptured intracranial aneurysms by surgical operation or DSA. All patients were examined with MSCT using these parameters:range:from foramen magnum to vertex; spiral scanning speed:0.6s/r; slice thickness:0.625 mm; table speed:9.38 mm/s; pitch:0.938:1; matrix:512×512; tube voltage:120 kV, tube current:360-400 mA. Using double-barreled high-pressure syringe, nonionic iodine contrast medium was injected via an antecubital vein 90-100 ml, followed by injection of normal saline 40-60 ml; injection rate: 4.0-4.5 ml/s; delay time:21-25 s. Reconstruction techniques included multi-planar reconstruction (MPR), maximum intensity projection (MIP) and volume rendering techniques (VR). CT images were evaluated by searching these parameters:location; maximum diameter and volume; the ratio of length and width; daughter aneurysms or not; single or multiple aneurysms. Software for statistical analysis used SPSS 15.0, the difference of statistical significance was established at P< 0.05.Results:1. The location of ruptured aneurysms:115 ruptured aneurysms,102 (102/115,88.7%) of them in the anterior circulation,13 (13/115,11.3%) of them in the posterior circulation.38 (38/115, 33.04%) of them in the anterior communicating artery, among them,16(16 /38,42.11%) patients had one side of hypoplastic or absent A1 segment of anterior cerebral artery.32 (32/115,27.83%) of them in the posterior communicating artery, and 70 (70/115,60.87%) of them in the anterior communicating artery and posterior communicating artery in sum.2. The maximum diameter of ruptured aneurysms:2-17.5 mm (6.72±3.32 mm). 37 (37/115,32.17%) ruptured aneurysms< 5 mm in the maximum diameter,23 of them (23/37,62.16%) in the anterior communicating artery and posterior communicating artery.72 (72/115,62.61%) ruptured aneurysms< 7 mm in the maximum diameter,43 of them (43/72,59.72%) in the anterior communicating artery and posterior communicating artery.3. The volume of ruptured aneurysms:13-2651 mm3 (369.65±187.74 mm3). 63 (63/115,54.78%) aneurysms< 200 mm3 in volume, mainly located in the anterior communicating artery and posterior communicating artery (39/ 63,61.9%), next in the carotid artery (9/63,14.29%).4. The ratio of length and width in ruptured aneurysms:24 (24/115,20.87%) aneurysms≤1.8,91 (91/115,79.13%) aneurysms> 1.8. Daughter aneurysms:67 (67 /115,58.26%) aneurysms with daughter aneurysms.5. Single or multiple aneurysms:single aneurysm in 96 patients (96/115,83.48%); multiple aneurysms in 19 patients (19/115,16.52%),19 ruptured aneurysms(group A, in which each patient had one responsible aneurysm), the maxmimum diameter of them was 3.6-16.4 mm (7.96±3.88 mm); the ratio of 15 (15 /19,78.95%) ruptured aneurysms> 1.8,9 (9/19,47.37%) ruptured aneurysms had daughter aneurysms; 23 unruptured aneurysms (group B) of multiple aneurysms, the maxmimum diameter of them was 2-6.5 mm (3.87±1.39 mm), the ratio of 5 (5/23,21.74%) unruptured aneurysms> 1.8, none of them had daughter aneurysm. The maxmimum diameter of group A was larger than group B, which had statistical significangce (P< 0.05).Conclusion:The CT performance of ruptured intracranial aneurysms had the following characteristics:1. Ruptured aneurysms mostly occured in the anterior circulation, particularly in the anterior communicating artery and posterior communicating artery. Nearly half patients of the ruputured aneurysms in the anterior communicating artery had one side of hypoplastic or absent A1 segment of anterior cerebral artery.2. Most of the ruptured aneurysms (the maximum diameter< 5 (7) mm or the volume< 200 mm3) located in the anterior communicating artery and posterior communicating artery, next in the carotid artery.3. The ratio of length and width in most ruptured aneurysms was> 1.8, most of the ruptured intracranial aneurysms had daughter aneurysms.4. Single aneurysm was more common than multiple aneurysms in the patients with ruptured aneurysm. The maximum diameter of ruptured aneurysms was larger than the unruptured aneurysms in the patients with multiple aneurysms, there was a statistical significance; the ratio> 1.8 and daughter aneurysms were more common in ruptured aneurysms than unruptured aneurysms.