[Intravascular ultrasound imaging and histological evaluation of the aorta]

It has been shown in several in-vitro studies that IVUS images correlate well with histology and angioscopy. The existing data on intravascular imaging of large-diameter elastic arteries are scant. The aim of this study was to compare the IVUS images of aorta with the reference method--histological section by evaluating the accuracy of measurements performed at corresponding aortic segments.

15 human aortic specimens were derived from post-mortem examination and in-vitro IVUS imaging was performed, including measurements of vessel diameters and cross-sectional areas in three specified areas. Corresponding regions of interest obtained with histology were subsequently evaluated and parameters matched to those by IVUS were calculated.

Total of 45 pairs of measurement were compared. Mean vessel internal diameter on IVUS was 14.4 mm (SD 2.7 mm) and intima thickness was 0.6 mm (SD 0.8 mm). The corresponding aortic internal diameter observed with histology was 13.2 (SD 2.6 mm) and intima thickness--0.3 mm (SD 0.03). An overall agreement between IVUS and histology specimens was high, yelling correlation ratio of 0.99. The highest level of agreement was observed for external vessel area validation--correlation ratio 0.98. The largest discrepancy was observed for intima and media thickness, with correlation ratios of 0.61 and 0.72, respectively.

Our data suggest that examination of aorta with intravascular ultrasound is feasible and may provide additional information in assessment of cardiovascular pathology. More complete risk stratification, which includes IVUS examination of aorta, is an important factor to determine the necessity for early preventive treatment, especially in patients with normal coronary arteries.