Objective To investigate the features of median arcuate ligament syndrome (MALS) in computed tomography angiography (CTA).

Methods The retrospective and descriptive study was conducted. The clinical and imaging data of 56 patients with MALS who were admitted to Ruijin Hospital, Shanghai JiaoTong University School of Medicine from November 2019 to October 2020 were collected. There were 30 males and 26 females, aged from 19 to 78 years, with a median age of 54 years. All 56 patients underwent CTA. Observation indicators: (1) CTA examination; (2) correlation analysis; (3) surgical situations. Measurement data with normal distribution were represented as Mean±SD. Count data were described as absolute numbers or percentages. Spearman correlation analysis with test level of 0.05 was used to analyze the correlation between celiac trunk stenosis and the distance between the original location of celiac trunk and original location of superior mesenteric artery and the minimum distance of celiac trunk and superior mesenteric artery.

Results (1) CTA examination. ① Celiac trunk stenosis: results of cross sectional examina-tion of CTA showed that of 56 patients, there were 2 cases of celiac trunk occlusion, 10 cases of severe stenosis, 9 cases of moderate stenosis and 35 cases of mild stenosis. Results of sagittal examination of CTA showed that of 56 patients, there were 2 cases of celiac trunk occlusion, 21 cases of severe stenosis, 15 cases of moderate stenosis and 18 cases of mild stenosis. ② Examination of patients with different degree of vascular stenosis: according to the results of sagittal examination of CTA, the 2 cases with celiac trunk occlusion were negative for aneurysms, aortic dissection or vascular variations but positive for compensated varix of the anterior and posterior pancreatico-duodenal arches. Of the 21 cases with celiac trunk severe stenosis, 2 cases were positive for aneurysms, 1 case was positive for aortic dissection, 7 cases were positive for compensated varix of the anterior and posterior pancreaticoduodenal arches, 8 cases were positive for collateral circula-tions of anterior and posterior pancreaticoduodenal archs and 8 cases were positive for vascular variation. Of the 15 cases with celiac trunk moderate stenosis, 2 cases were positive for aneurysms, 3 cases were positive for aortic dissection, 2 cases were positive for compensated varix of the anterior and posterior pancreaticoduodenal arches, 4 cases were positive for collateral circulations of anterior and posterior pancreaticoduodenal archs and 7 cases were positive for vascular variation. Of the 18 cases with celiac trunk mild stenosis, 1 case was positive for aneurysms, 2 cases were positive for aortic dissection, 7 cases were positive for collateral circulations of the anterior and posterior pancreaticoduodenal arches, 6 cases were positive for vascular variation. All 56 patients were negative for ischemia of liver, spleen and stomach. ③ Original location of celiac trunk: of 56 patients, there were 43 cases had celiac trunk originated horizontally from the lower edge of T12 vertebral body, 2 cases had celiac trunk originated from the middle of T12 vertebral body, 1 case had celiac trunk originated from the upper part of T12 vertebral body, 7 cases had celiac trunk originated from the upper part of L1 vertebral body, 1 case had celiac trunk originated from the middle of L1 vertebral body and 2 cases had occluding celiac trunk. (2) Correlation analysis: results of sagittal observation on CTA examination showed the distance between the original location of celiac trunk and original location of superior mesenteric artery of the 56 patients was (6.0±4.0) mm. The distance between the original location of celiac trunk and original location of superior mesenteric artery of patients with celiac trunk mild, moderate or severe stenosis were (6.2±2.8)mm, (8.1±4.4)mm and (5.3±3.2)mm respectively. There were 23 cases of the 56 patients had the distance between the original location of celiac trunk and original location of superior mesenteric artery <5 mm. Results of correlation analysis showed that the degree of celiac trunk stenosis was not related to the distance between the original location of celiac trunk and original location of superior mesenteric artery (r=‒0.205, P>0.05). Results of sagittal observation on CTA examination showed the shortest distance between celiac trunk and superior mesenteric artery of the 56 patients was (3.8±2.4)mm. The shortest distance between celiac trunk and superior mesenteric artery of patients with celiac trunk mild, moderate or severe stenosis were (4.2±2.0)mm, (4.4±3.3)mm and (3.0±1.9)mm, respectively. There were 45 cases of the 56 patients had the shortest distance between celiac trunk and superior mesenteric artery <5 mm. Results of correlation analysis showed that the degree of celiac trunk stenosis was not related to the shortest distance between celiac trunk and superior mesenteric artery (r=‒0.249, P>0.05). (3) Surgical situations: of 56 patients, 2 cases were positive for clinical symptoms of abdominal pain, 54 cases were negative for clinical symptoms, 4 cases under-went surgical treatment and 52 cases not underwent surgical treatment. Of the 4 cases undergoing surgical treatment, 2 cases with abdominal pain were diagnosed as MALS by upper abdominal CTA. Celiac trunk of the 2 cases were severe stenosis and stents implantation under celiac arteriography were performed. Results of postoperative CTA showed celiac trunk was negative for obvious stenosis. The other 2 cases who were negative for clinical symptoms of MALS were planed to pancreaticoduo-denectomy for pancreatic head tumor. Results of preoperative CTA showed severe stenosis of celiac trunk and arterial bypass grafting was performed for the 2 cases during pancreaticoduodenectomy to alleviate liver ischemia caused by gastroduodenal artery ligation which would avoid the incidence of postoperative MALS associated complications. Result of postoperative CTA three-dimensional reconstruction showed the bypass vessel was unobstructed.

Conclusion Based on sagittal result of CTA examination, the stenosis of celiac trunk, the anatomical relationship between celiac trunk and arcuate ligament and the original location of celiac trunk of MALS patients can be evaluated.