Thin-section multidetector CT angiography of renal artery stents

This study was undertaken as a pilot investigation to compare multidetector CT angiography with conventional catheter angiography for the visualization of the renal artery lumen after renal artery stent placement.

CT angiography was performed within 24-48 hr of renal artery stent placement in 15 patients. Two patients had bilateral stents, resulting in a total of 17 stents. CT angiography was performed using a multidetector scanner and a bolus of IV contrast material with the scanning delay determined by a small-volume timing bolus. A volumetric data set was acquired through the stented arteries in the axial plane using a 4.0 x 1.25 mm detector configuration and a pitch of 3:1. The stent lumen diameter, as measured on direct CT angiography and curved multiplanar reformations in both the axial and coronal planes, was compared with that measured on catheter angiography.

The lumina of all 17 stents were well visualized and patent on both CT angiography and catheter angiography. Anatomic definition, including stent position and wall apposition in the renal artery, correlated well with catheter angiography. The diameter of the renal artery stent lumen measured on catheter angiography (mean, 5.9 +/- 1.3 mm) was greater than that on CT angiography (mean stent lumen diameter for direct axial plane was 4.6 +/- 1.0 mm, for curved multiplanar reformations in the axial plane was 4.3 +/- 1.0 mm, and for curved multiplanar reformations in the coronal plane was 4.4 +/- 1.0 mm) in 14 (82%) of 17 stents.

CT angiography produced interpretable multiplanar images of the renal artery, even with a metallic stent in place, and was adequate for determining stent patency. Compared with catheter angiography, the intrastent luminal diameter was underestimated in most patients who underwent CT angiography.