Accurate assessment of abdominal aortic aneurysm with intravascular ultrasound scanning: Validation with computed tomographic angiography

Purpose: The purpose of this study was to assess the accuracy of intravascu lar ultrasound (IVUS) parameters of abdominal aortic aneurysm, used for end ovascular grafting, in comparison with computed tomographic angiography (CT A). Methods: This study was designed as a descriptive study. Between March 1997 and March 1998, 16 patients with abdominal aortic aneurysms were studied w ith angiography, IVUS (12.5 MHz), and CTA. The length of the aneurysm and t he length and lumen diameter of the proximal and distal neck obtained with IVUS were compared with the data obtained with CTA. The measurements with I VUS were repeated by a second observer to assess the reproducibility. Tomog raphic IVUS images were reconstructed into a longitudinal format. Results: IVUS results identified 31 of 32 renal arteries and four of five a ccessory renal arteries. A comparison of the length measurements of the ane urysm and the proximal and distal neck obtained with IVUS and CTA revealed a correlation of 0.99 (P < .001), with a coefficient of variation of 9%. IV US results tended to underestimate the length as compared with the CTA resu lts (0.48 +/- 0.52 cm; P < .001). A comparison of the lumen diameter measur ements of the: proximal and distal neck derived from IVUS and CTA showed a correlation of 0.93 (P < .001), with a coefficient of variation of 9%. IVUS results tended to underestimate aneurysm neck diameter as compared with CT A results (0.68 +/- 1.76 mm; P = .006). Interobserver agreement of IVUS len gth and diameter measurements showed a good correlation (r = 1.0; P < .001) , with coefficients of variation of 3% and 2%, respectively, and no signifi cant differences (0.0 +/- 0.16 cm and 0.06 +/- 0.36 mm, respectively). The longitudinal IVUS images displayed the important vascular structures and im proved the spatial insight in aneurysmal anatomy. Conclusion: Intravascular ultrasound scanning results provided accurate and reproducible measurements of abdominal aortic aneurysm. The longitudinal r econstruction of IVUS images provided additional knowledge on the anatomy o f the aneurysm and its proximal and distal neck.