Body proportions and age-related imaging features in children and adolescents with suspected median arcuate ligament syndrome: a CT case-control study

This study aimed to compare body-proportion parameters, vertebral dimensions, and spatial features of the proximal CA course between children and adolescents with suspected MALS and controls using contrast-enhanced CT, and to evaluate the associations of these parameters with age and CA stenosis severity. This retrospective case-control study included 45 children and adolescents with suspected MALS and 45 controls frequency-matched for age and sex who underwent contrast-enhanced CT between January 2015 and July 2023. Measurements included abdominal circumference, L1 vertebral body dimensions and exploratory body-proportion ratios, the abdominal aorta-CA (AA-CA) angle, and CA-median arcuate ligament (MAL) and superior mesenteric artery (SMA)-MAL distances. Patients in the suspected MALS group were stratified by stenosis severity and age (≤ 12 vs. >12–18 years). Multivariable logistic regression, receiver operating characteristic analysis, ordinal logistic regression, and Spearman correlation were performed. Compared with controls, the suspected MALS group had a lower abdominal circumference/L1 height ratio ( P = 0.028), a larger AA-CA angle ( P = 0.002), and shorter CA-MAL and SMA-MAL distances ( P = 0.001 and P < 0.001). After adjustment for age and sex, a lower abdominal circumference/L1 height ratio, a larger AA-CA angle and a shorter SMA-MAL distance remained associated with membership in the suspected MALS group. In the development cohort, the combined model had an apparent area under the curve of 0.899 (95% CI, 0.837–0.962). Within the suspected MALS group, older patients had greater CA stenosis ( P = 0.003) and a larger AA-CA angle ( P < 0.001) than younger patients. Only age was independently associated with a higher stenosis category ( P = 0.035). Stenosis severity correlated positively with age, vertebral dimensions, and AA-CA angle and negatively with abdominal circumference/L1 height ratio (all P < 0.05). Visceral artery origin levels and MAL and diaphragmatic crus thicknesses did not differ significantly between groups. In this retrospective exploratory study, a lower abdominal circumference/L1 height ratio, a larger AA-CA angle, and a shorter SMA-MAL distance were independently associated with membership in the suspected MALS group, whereas older age was associated with greater CA stenosis severity within the suspected MALS group. These findings suggest that relative abdominal size, proximal CA deflection, and vessel–ligament spacing may provide complementary information in the CT assessment of suspected pediatric MALS, while age should be considered when interpreting stenosis severity. Independent validation is needed to establish the clinical relevance of these findings.