Which classification system best represents the inferior mesenteric artery? An imaging-based analysis with a review...

The inferior mesenteric artery (IMA) serves as the primary blood supply for the hindgut, extending from the distal transverse colon to the rectum. Variations in the anatomy of the IMA are well-documented, and numerous classification systems have been developed to describe these anatomical differences. These variations can involve differences in the origin, course, and branching patterns of the IMA. The present study aimed to analyze the anatomy of the IMA with respect to the available classification systems in the literature.

Results from 74 consecutive patients who underwent abdominal computed tomography angiography (CTA) were evaluated.

The most common vertebral level of departure of the IMA was found to be the body of the L3 vertebra. The most common IMA type according to the Zhang classification was found to be Type IA, which occurred in 25 of the studied patients (35.71%). The most common IMA type according to the Zebrowski classification was found to be Type B (n = 26; 41.27%), followed by Types C and H (n = 14; 22.22%). The most common order of departure of the branches of the IMA was found to be the left colic artery (LCA) followed by the common departure of the sigmoid trunk and superior rectal artery (SRA). The median diameter of the IMA at its origin was found to be 3.49 mm (LQ = 3.09; HQ = 3.70) in females and 3.74 mm (LQ = 3.44; HQ = 4.05) in males (p = 0.01).

The results of the present study demonstrate that the most comprehensive but also specific classification system of the IMA was the McSweeney classification. It is hoped that the results of the present study may be useful to physicians performing various gastrointestinal and endovascular procedures, such as laparoscopic ligation of the IMA or embolization procedures.