Quantitative Assessment of the Morphology of Renal Arteries from X-ray Images: Quantitative Vascular Analysis

Rationale and Objectives:With the advent of interventional vascular procedures, objective and reproducible tools are needed to assist clinical decision-making and to assess intervention efficacy. The success of quantitative coronary arteriography (QVA) in objectively assessing cardiovascular morphology has initiated the software development for quantitative analysis of peripheral vasculature. The objective of this study was to evaluate the applicability and quality of a new QVA package applied to renal arteries. Methods:A calibration method was developed using markers mounted on a catheter’s shaft, ensuring accurate calibration even with small catheter sizes. Given the high prevalence of ostial stenoses in peripheral vessels, a dedicated vessel analysis method was developed to assess these stenoses. Its reproducibility was determined in renal angiography. Variance component analysis was performed to evaluate sources of variability, using angiograms from 74 patients suspected of renovascular hypertension. Results:For intraobserver variability, the 95% confidence intervals of differences in percent diameter stenosis and minimal lumen diameter were −1.99%–1.04% (P = 0.53, n = 48) and −0.081 mm–0.023 mm (P = 0.27, n = 48), respectively. For the interobserver variability, intervals were −1.86%–2.80% (P = 0.69, n = 66) and −0.46 mm–0.053 mm (P = 0.12, n = 46), respectively. Conclusions:The contribution of intraobserver variation was negligible. The contribution of interobserver variation for different parameters was negligible or comparable with the variation caused by image acquisition. These conclusions demonstrate that QVA can reproducibly measure renal artery geometry.