Should We Be Concerned? Comparison of Catheter and CT Angiogram for Arterial Distensibility at the Site of Carotid Stenosis during Catheter Angiography

Purpose: During catheter angiogram (CA) there is momentary increase in intravascular volume and pressure due to intra-arterial injection that can potentially cause vascular distention at the stenotic site, whereas on CT angiogram (CTA) is unlikely due to intravenous administration. Methods: CA and CTA of the carotid artery from 29 patients were retrospectively studied. CA and CTA were obtained for each patient. Curved sagittal MPRs mirroring the carotid artery on CA were used to measure the diameter at stenosis and at the distal lumen. Mural plaque calcium content was graded on axial CTAs. Results: Accounting for repeated measurements, the likelihood that the lumen diameter from CA will be larger than CTA was higher at stenosis than distal to it but the difference in lumen diameters at stenosis was similar to CTA. There is insufficient evidence that intra-arterial hand-injection during CA leads to underestimation of the degree of stenosis. Percentage stenosis using the NASCET criteria differed between the 3 measurements, post hoc analysis showed significant difference between CA and axial CTA (p < 0.0001), but not between CA and curved sagittal CTA (p > 0.99). The difference in lumen diameter did not depend on our calcium grading (p = 0.484). Conclusions: There is insufficient evidence to suggest that intra-arterial hand-injection contributes to vessel distention and underestimation of percent stenosis during CA in this study. Mural plaque calcium does not affect the degree of stenosis on CTA.