In a contrast enhanced MR angiography of the abdominal arteries, the IV gadolinium would enhance in which order?

In a contrast-enhanced MR angiography of the abdominal arteries, the order of enhancement primarily depends on the arterial supply and the hemodynamics of blood flow through these vessels after administration of gadolinium-based contrast material.

The celiac trunk originates from the aorta and supplies the upper abdominal organs, thus it typically receives the contrast first. Following the celiac trunk, the superior mesenteric artery, which branches off the aorta just below the celiac trunk, enhances next; it supplies blood to a significant portion of the intestines. The renal arteries, which branch off the aorta further down than the superior mesenteric artery, will enhance after the mesenteric arteries due to their location and blood flow dynamics. Finally, the inferior mesenteric artery, which originates even further along the aorta, will enhance last among these named arteries.

Therefore, the correct order of enhancement is: celiac trunk first, followed by the superior mesenteric artery, then the renal arteries, and finally the inferior mesenteric artery. This rationale supports the selection of the fourth option, which precisely reflects this sequence based on anatomical and physiological principles.