Multidetector computed tomography angiographic imaging of the inferior mesenteric artery: Aberrant branches and branching patterns

Abstract

Background : Most of colonic polyp and colorectal carcinoma are found in inferior mesenteric artery (IMA) supplied segments. Complication such as bleeding is crucial role for endovascular embolization and chemotherapy. Knowledge of vascular anatomy is important for successful interventional procedure.

Objective : To determine the branching patterns and different aberrant arterial branches of IMA in Thai population by using multidetector computed tomography (MDCT) angiography. Setting Department of Radiology, King Chulalongkorn Memorial Hospital.

Study design : Retrospective descriptive study.

Methods : A total of 165 patients who underwent MDCT angiography of the whole aorta from January 2009 to December 2011 were retrospectively reviewed. The vertebral level of IMA origin, branching pattern and the presence of aberrant arterial branches were recorded. Researcher and another experienced radiologist performed image analysis in consensus.

Results : IMA originates from the abdominal aorta at any level between superior endplate of second lumbar vertebra and inferior endplate of forth lumbar vertebra. The body of third lumbar vertebra is the most frequent level of origin, 49 cases (29.7%). Five branching patterns are founded. The most frequent pattern is sigmoid artery (SA) branches off from superior rectal artery (SRA), 57 cases (34.5%). One of five branching patterns is newly discovered pattern which are two left colic arteries (LCAs) branch off from IMA, 20 cases (12.1%). Only two cases with aberrant branches were observed, including IMA branching from superior mesenteric artery (SMA) and LCA branches off from SMA (1.2%).

Conclusions : There were anatomical variations of IMA, including level of origin, branching patterns and aberrant branches. In the Thai population, the branching pattern and aberrant branches show some variation from the previously reported cases. Using of MDCT angiography provides good information for detection of vascular variation before interventional procedure.