Detection of Neck Recanalization with Follow-up Contrast-enhanced MR Angiography after Renal Artery Aneurysm Coil Embolization

embryologic development, there is a metameric disposition of the arteries of the trunk. These trunk arteries provide blood supply to the parietal wall (ie, posterior arteries), to the urogenital tract (ie, lateral arteries) and to the intestinal tract (ie, anterior arteries). During evolution, regression of several of these ventral, metameric arteries is observed, as well as the regression of the ventral anastomoses of these metameric arteries. This embryonic development eventually results in the formation of three residual anterior arteries at the 10th, 13th, and 21st or 22nd root, respectively, corresponding to celiac, superior mesenteric, and inferior mesenteric arterial anatomy as seen in the adult vasculature. However, in some cases the mechanism of regression of metameric arteries and of their ventral anastomoses can be distorted, resulting in different anatomic variants. In the present case, it can be hypothesized that the proximal anastomosis between the root, which later formed the superior and inferior mesenteric artery, persisted and progressively developed at the level of the initial 21st or 22nd root, the normal origin of the inferior mesenteric artery. Additionally, persistence of another root, located at the level of the 12th to 14th root, could have resulted in the presence of an accessory branch, originating from the aorta at the level of the first lumbar vertebra and supplying a part of the ileum. Finally, it is clear that the knowledge of variant or aberrant vascular anatomy is of importance so as not to overlook a potential source of gastrointestinal hemorrhage during visceral angiography.