MR Venography of the Inferior Mesentery Vein

Objective: To evaluate on three-dimensional (3D) dynamic contrast-enhanced (DCE) MR venography (MRV), the visibility of the inferior mesenteric vein (IMV), its insertion pattern into the portal system, and the difference of IMV diameters between healthy subjects and patients with cirrhosis.

Materials And Methods: Two hundred and seventeen consecutive patients who had abdominal 3D DCE MRI was included in this study. The original image data of 3D DCE MRI was used to generate multiple planar volume reconstruction (MPVR) images, which were evaluated for visualization of the IMV and its pattern of insertion into the portal system. The diameter of IMV was measured and compared in 24 patients with cirrhosis (Cirrhosis Group) and in 30 patients without hepatic lesions or liver disease (Healthy Group).

Results: In the 217 patients, the frequencies of visualization of IMV, grade 1 order branches and grade 2 order branches were, respectively, 88%, 24% and 9%. The IMV inserted into the splenic vein (SV), the portal confluence and the superior mesenteric vein (SMV) in 45%, 18% and 37%, respectively. Among patients with cirrhosis, 12.5% had IMV diameter larger than 5.1mm, although there was no significant difference between cirrhosis and healthy groups (P>0.05). However, the diameters of the main portal vein (MPV), SV and SMV were significantly larger in the Cirrhosis Group (P<0.05).

Conclusion: The IMV and its branches can be depicted well by 3D DCE MRV. The most common insertion of the IMV is into the splenic vein. A minority of patients with cirrhosis had dilatation of the IMV.