Radiological evaluation of superior mesenteric artery syndrome: are aortomesenteric angle and distance measurements reliable?

Abstract

Objectives: To evaluate the interobserver and intraobserver consistency of aortomesenteric angle (AMA) and aortomesenteric distance (AMD) measurements in diagnosing superior mesenteric artery syndrome (SMAS), and to assess their reliability as diagnostic parameters. Methods: This retrospective study analyzed 200 abdominal CT scans of patients (124 females, 76 males; aged 17–42) with a preliminary diagnosis of SMAS between May 2021 and March 2024. AMA and AMD were measured on sagittal and oblique-sagittal images by three radiologists at two different times, independently and blinded to clinical data. Intraobserver and interobserver variability was evaluated using nonparametric statistical tests, with p<0.05 considered significant. Diagnostic thresholds were set at 22° for AMA and 8 mm for AMD. Results: AMA measurements showed significant interobserver and intraobserver variability (p<0.05), while AMD measurements were reproducible and consistent (p>0.05). Variability in AMA led to diagnostic discrepancies in 9.1–10.4% of cases, compared to only 0.5–1.2% for AMD. These results indicate that AMA is less reliable and prone to user-dependent errors, whereas AMD offers greater diagnostic accuracy. Conclusion: AMA measurements are influenced by factors such as patient positioning and respiratory phase, contributing to their inconsistency. AMD, in contrast, demonstrates low variability and high reliability, making it a more robust parameter in SMAS diagnosis. The study emphasizes the need to prioritize AMD over AMA in the diagnostic workflow for SMAS. AMD is a consistent and reliable parameter for SMAS diagnosis, while AMA demonstrates significant variability and potential for misdiagnosis.

Keywords

• Aortomesenteric angle
• aortomesenteric distance
• computed tomography
• reliability
• superior mesenteric artery
• syndrome

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