颅内未破裂动脉瘤形态学对高分辨率MR管壁成像瘤壁强化的影响因素分析

Analysis of influencing factors of the effect of the morphology of unruptured intracranial aneurysms on aneurysm wall enhancement of vascular wall with high-resolution magnetic resonance imaging

目的探讨颅内未破裂动脉瘤形态学对高分辨率磁共振管壁成像下瘤壁强化的影响因素。方法回顾性连续纳入2015年1月至2016年12月第二军医大学附属长海医院颅内未破裂动脉瘤患者68例(共86个动脉瘤)的临床及影像资料,应用MR管壁成像技术进行动脉瘤扫描,并通过对比剂增强前后影像学特征以判断瘤壁强化。根据是否存在瘤壁异常强化分为强化组(32例,34个动脉瘤)与非强化组(45例,52个动脉瘤)。因部分患者同时存在强化和非强化动脉瘤,故两组按强化与否的病例数分别计算。应用三维影像数据计算动脉瘤的形态学参数,包括动脉瘤大小、高宽比、体积比、体颈比、横长比、瓶颈因子及入射角度。运用单因素分析与多因素Logistic回归分析,明确瘤壁强化的形态学影响因素。结果 (1)共34个(39.5%)动脉瘤存在瘤壁强化,52个(60.5%)动脉瘤无瘤壁强化。两组性别、年龄、高血压病、糖尿病、吸烟、蛛网膜下腔出血家族史、动脉瘤部位的差异均无统计学意义(均P>0.05)。(2)强化组动脉瘤大小、高宽比、体积比、体颈比、瓶颈因子水平均大于非强化组,组间差异均有统计学意义[9.19(6.54,11.40)mm比5.31(4.17,7.37)mm,1.18(1.01,1.69)比0.91(0.72,1.25),3.62(2.30,4.63)比2.18(1.37,2.76),1.52(1.25,1.99)比1.19(1.03,1.51),1.21(1.11,1.69)比1.05(0.94,1.31);均P<0.01];强化组不规则形态动脉瘤比例高于非强化组,组间差异有统计学意义[55.9%(19/34)比17.3%(9/52),P<0.01];组间动脉瘤纵横比及入射角度的差异均无统计学意义(均P>0.05)。(3)由于高宽比、体积比、体颈比及瓶颈因子与瘤体大小有关联,故将动脉瘤大小、入射角度和不规则形态纳入多因素Logistic回归分析,结果显示动脉瘤大小(OR=3.727,95%CI:1.993~6.971,P<0.01)、不规则形态(OR=3.990,95%CI:1.219~13.065,P=0.022)为动脉瘤瘤壁强化的独立危险因素。结论颅内未破裂动脉瘤的大小与不规则形态是瘤壁异常强化的独立危险因素,高分辨率MR管壁成像可能成为颅内动脉瘤破裂风险评估的有效无创影像学方法。

Objective To investigate the influencing factor of the morphology of unruptured intracranial aneurysms for aneurysm wall enhancement under the high-resolution magnetic resonance imaging.M ethods From January 2015 to December 2016,the clinical and imaging data of 68 consecutive patients with unruptured intracranial aneurysm（ 86 aneurysms） in Changhai Hospital,the Second Military Medical University were enrolled retrospectively. Vascular wall imaging technology was used to conduct aneurysm scan,and the aneurysm wall enhancement was identified by the imaging features before and after contrast enhancement. They were divided into either an enhancement group（ n = 32,34 aneurysms） or a non-enhancement group（ n = 45,52 aneurysms） according to whether having the abnormal enhancement of aneurysm wall or not（ because some patients also have enhanced aneurysms and non-enhanced aneurysms,the number of cases of the enhanced or not was calculated seperately in both groups）. Morphological parameters were calculated by 3 D image data,including aneurysm size,ratio of height to width,volume ratio,dome-to-neck ratio,transverse length ratio,bottleneck factor,and inflow angle. Univariate and multivariate logistic analyses were used to determine the morphological influence factors of aneurysm wall enhancement.Results（ 1） A total of 34（ 39. 5%） aneurysms had aneurysm wall enhancement and 52（ 60. 5%）aneurysms did not have aneurysm wall enhancement. There were no significant differences in sex,age,hypertension,diabetes,smoking,family history of subarachnoid hemorrhage,and aneurysm site in both groups（ all P 0. 05）.（ 2） The aneurysm size,ratio of height to width,volume ratio,dome-to-neck ratio,and bottleneck factor in the enhancement group were larger than those of the non-enhancement group. There were significant differences between the 2 groups（ 9. 19 [6. 54,11. 04]mm vs. 5. 31 [4. 17,7. 37]mm,（ 1. 18 [1. 01,1. 69]vs. 0. 91 [0. 72,1. 25],（ 3. 62 [2. 30,4. 63]vs. 2. 18 [1. 37,2. 76],1. 52 [1. 25,1. 99] vs. 1. 19 [1. 03,1. 51],and 1. 21 [1. 11,1. 69] vs. 1. 05 [0. 94,1. 31],all P 0. 01）. The proportion of irregular morphologic aneurysms in the enhancement group was higher than that in the non-enhancement group. There was significant difference between the 2 groups（ 55. 9% [19/34] vs. 17. 3% [9/52 ],P 0. 01）. There were no significant differences in transverse length ratio and inflow angle between the 2 groups（ all P 0. 05）.（ 3） Because the ratio of height to width,volume ratio,dome-to-neck ratio,and bottleneck factor were related to the aneurysm size,the aneurysm size,inflow angle,and irregular shape were included in the multivariate logistic regression analysis. The results showed that aneurysm size（ OR,3. 727,95% CI1. 933-6. 971,P 0. 01） and irregular shape（ OR,3. 990,95% CI 1. 219-13. 065,P = 0. 022） were the independent risk factors for aneurysm wall enhancement. Conclusions The size and irregular shape of unruptured intracranial aneurysms are the independent risk factors for aneurysm wall enhancement. Highresolution magnetic resonance wall imaging may become an effective and noninvasive imaging method for evaluating the ruptured risk of intracranial aneurysms.