| Objective:There are controversial topics about intracranial aneurysm in clinical research work, for example the risk factors of intracranial aneurysm, the mechanism for rupture, as well as the management of unruptured aneurysms. while the America and European guidelines for unruptured intracranial aneurysms(5mm) recommended conservative treatment. But there are reports[6] that diameter <10mm for ruptured intracranial aneurysms is in 87.9%, accounting for 71.8% of the diameter of <7mm, and the Japanese research[20] for 448 cases of unruptured aneurysms(5mm) were studied prospectively followed(the average of 41 months), found that the diameter of aneurysm rupture risk is much higher in 4-5mm..At the same time, we found that a large number of unruptured aneurysms in clinical work(less than 5mm) and small aneurysms accounted for 59% in our center. We retrospect studied of ruptured intracranial small aneurysms and their clinical and morphological factors related to rupture, and explore the risk factors concerning rupture of small intracranial aneurysms in order to provide criterion for whether it is necessary to intervene them. Methods:180 cases of small solitary intracranial aneurysms which received Cerebral angiography and have detailed clinical records and imaging data were analyzed. Among the 180 cases, 149 aneurysms were ruptured and 31 remained intact. Imaging features of two groups were compared including inflow angle, AR value(Height/Neck), SR value(Dmax/L), shape, location and daughter sac of aneurysm and clinical risk factors(age, gender, hypertension, history of subarachnoid hemorrhage). The significance of disparity between these two groups were analyzed by T test(or Rank sum test), Chi-squared test featuring single factor and two independent samples as well as Logistic regression analysis. Results:68 patients of 149 ruptured aneurysms have daughter sac, accounting for 45.6%; Only 6 patients of 31 unruptured aneurysms have ascus, accounting for 19.4%; Asci of ruptured aneurysms are more common than unruptured aneurysms(single factor analysis, P =0.007); As regard to location analysis of aneurysms, anterior communicating artery aneurysms amount to 58 among the 149 rupture cases, accounting for 38.9%. 2 cases of ICA ophthalmic artery takes up 1.3%. 4 case of top of the basilar artery holds 2.7%. Among the 31 unruptured cases, 2 cases of anterior communicating artery aneurysms accoutes for 6.5%.13 cases of ICA ophthalmic artery takes up 41.9%; 1 case of top of the basilar artery holds 3.2%. Two groups have significant statistical difference(c2=60.30,P =0.001);AR value of ruptured group(1.76±0.72),SR value(1.90±0.81), inflow angle(123.9°±23.21°); AR value of unruptured group(1.35±0.48), SR value(1.31±0.67), inflow angle(95.96°±20.2°). The single factor statistical analysis of two groups in AR(P = 0.001), SR(P =0.001) and inflow angle(P <0.001) present apparent difference. Logistic Regression Analysis shows that the location of aneurysms(OR=1.347,P =0.002),the inflow angle(OR=1.057, P <0.001)and SR(OR=2.726, P =0.047)are relative risk factors for the rupture of intracranial small aneurysms. However, clinical risk factors such as hypertension(P =0.53),history of SAH(P =0.83)、gender(P =0.24)、age(P =0.70)bear no statistical meaning. Conclusion:correlation risk factors which make small ruptured intracranial aneurysms distinctive from unruptured ones are as follows: 1, location: located in anterior communicating artery and the top of the basilar artery; 2, SR value >1.90±0.81; 3, inflow angle >123.9°±23.21°.The findings could be a reference to decide to intervene the samll unruptured intracranial aneurysms. |
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