Purpose: To prospectively assess the diagnostic accuracy of 64-detector computed tomographic (CT) renal artery (RA) angiography for the evaluation of RA in-stent restenosis (ISR) by using selective catheter RA angiography as the reference standard.
Materials and Methods: Institutional review board approval and written informed consent were obtained. Eighty-six patients (46 men, 40 women; mean age ± standard deviation, 71 years ± 9) with 95 RA stents were examined with 64-detector CT RA angiography by experienced radiologists 1 day before selective catheter RA angiography was performed by experienced cardiologists. Each group was blinded to the results of the other imaging method. For image reconstruction, a standard (R25f) and an edge-enhancing (B46f) kernel were chosen. An ISR of more than 50% was considered as hemodynamically significant. Sensitivity, specificity, and positive and negative predictive values for the detection of ISR by using CT RA angiography were calculated.
Results: At CT RA angiography, 93 (98%) of 95 stents were assessable for diagnosis. Two stents could not be evaluated owing to hardening artifacts affected by vessel calcifications. All nine cases of significant ISR seen at selective catheter RA angiography were correctly diagnosed by using CT RA angiography, giving a sensitivity of 100% and a negative predictive value of 100%. One case of nonsignificant ISR seen at selective catheter RA angiography was interpreted as significant by using CT RA angiography, giving a specificity of 99% and a positive predictive value of 90%. In four of 78 patients without ISR seen at selective catheter RA angiography, CT RA angiography showed nonsignificant ISR, giving a specificity of 95% and a positive predictive value of 56%.
Conclusion: Sixty-four-detector CT RA angiography can provide an excellent noninvasive technique to help detect and evaluate ISR within the RA stents used in our study.