基于CT血管成像的孤立性肠系膜上动脉夹层患者Riolan弓的影像解剖学观察

目的 探讨孤立性肠系膜上动脉夹层（ISMAD）患者CT血管成像（CTA）Riolan弓的显示率、管径大小及其临床意义。方法 回顾性病例对照研究。纳入2015年1月—2020年1月中山大学附属第一医院放射诊断科76例临床资料及腹部CTA资料完整的ISMAD患者作为ISMAD组,其中男69例、女7例,年龄39~78（55.0±8.6）岁;选取2020年7月—2021年7月同一医院150例腹部CTA无异常发现的受检者作为对照组,其中男91例、女59例,年龄20~83（54.2±13.2）岁。基于CTA影像评估并比较2组观察对象完整Riolan弓的显示率及其管径的大小;按Yun分型标准将ISMAD组分为Ⅰ型、Ⅱa型、Ⅱb型和Ⅲ型,比较Riolan弓显示率与管径在不同Yun分型间的差异。结果 ISMAD组和对照组的年龄比较差异无统计学意义（t=0.55,P=0.585）;ISMAD组男性占90.8%（69/76）,高于对照组的60.7%（91/150）,差异有统计学意义（χ²=22.14,P<0.001）。ISMAD组和对照组Riolan弓的显示率分别为84.21%（64/76）和31.33%（47/150）,其中男性分别为85.51%（59/69）和34.07%（31/91）、女性分别为5/7和27.12%（16/59）,组间比较差异均有统计学意义（P值均<0.05）,组内性别间比较差异均无统计学意义（P值均>0.05）。ISMAD组和对照组Riolan弓管径分别为（2.61±0.58）mm和（2.14±0.35）mm,ISMAD组大于对照组,差异有统计学意义（t=6.49,P<0.001）。ISMAD组不同Yun分型患者Riolan弓显示率及管径分别为：Ⅰ型75%（18/24）和（2.35±0.44）mm,Ⅱa型76.92%（20/26）和（2.40±0.33）mm,Ⅱb型19/19和（2.86±0.65）mm,Ⅲ型7/7和（3.20±0.66）mm。不同Yun分型间总体比较,Riolan弓显示率差异有统计学意义（P=0.043）,管径差异有统计学意义（F=18.26,P<0.001）;Ⅱb型和Ⅲ型的管径分别高于Ⅰ型和Ⅱa型,差异均有统计学意义（P值均<0.05）。结论 ISMAD患者的CTA Riolan弓显示率明显高于非ISMAD对照者,且管径增粗明显,间接验证了Riolan弓在ISMAD中的代偿作用;Riolan弓管径的大小可用于评估ISMAD管腔狭窄的程度。

Imaging anatomy of Riolan's arch in patients with isolated superior mesenteric artery dissection based on CT angiography

Objective To investigate the occurrence and the diameter of Riolan's arch in patients with isolated superior mesenteric artery dissection (ISMAD) . Methods The retrospective case-control study was conducted. Seventy-six cases (69 males and 7 females) of ISMAD (case group) with complete clinical and abdominal CT angiography (CTA) data were obtained from the Department of Radiology of the First Affiliated Hospital of Sun Yat-Sen University from January 2015 to January 2020 and included as the case group. A total of 150 subjects who underwent abdominal CTA without abnormal findings were selected from July 2020 to July 2021 as the control group. The occurrence and diameter of Riolan's arch were evaluated and compared on CTA images. The case group was divided into four subgroups according to Yun classification, and the occurrence and diameter of Riolan's arch were compared. Results The ages of patients in the case and control groups were (55.0±8.6) years and (54.2±13.2) years, respectively, and no significant difference was found between the two groups (t=0.55, P=0.585). Male accounted for 90.8% (69/76) in the case group, which was higher than that in the control group (60.7%, 91/150), and the difference was statistically significant (χ²=22.14, P<0.001). The incidence rates of Riolan's arch were 84.21% (64/76) in the case group and 31.33% (47/150) in the control group as well as 85.51% (59/69) and 34.07% (31/91) in the male group, and 5/7 and 27.12% (16/59) in the female group, respectively. Statistically significant differences were found among all groups (all P values <0.05), but no statistically significant differences were detected between genders within the group (all P values >0.05). The diameter of Riolan's arch was (2.61±0.58) mm in the case group and (2.14±0.35)mm in control group, and the differences was statistically significant (t=6.49, P<0.001). The occurrence and average diameter of the Riolan's arch in each subgroup were as follows: 75%(18/24) and (2.35±0.44) mm (Type Ⅰ), 76.92% (20/26) and 2.40±0.33 mm (Type Ⅱa), 19/19 and (2.86±0.65) mm (Type Ⅱb), and 7/7 and (3.2±0.66) mm (Type Ⅲ). Statistically significant difference in the occurrence of Riolan's arch was found in each subgroup (P=0.043), and significant differences in the diameter of Riolan's were detected (P<0.001). Conclusion The occurrence of Riolan's arch in patients of ISMAD was higher than that in the control group, and the caliber obviously dilated. These findings indirectly verify the compensation in ISMAD. Hence, Riolan's arch can easily evaluate the classification of ISMAD.