INTRAVASCULAR ULTRASOUND IMAGING OF ATHEROSCLEROTIC RENAL-ARTERIES - COMPARISON BETWEEN IN-VITRO AND IN-VIVO STUDIES

Background. Intravascular ultrasound (IVUS) imaging, a new modality, m ay be feasible and useful for the assessment of atherosclerotic renal arteries. However, comparison between in vivo and in vitro studies to confirm pathological changes corresponding with IVUS findings obtained from renal arteries was not fully evaluated. Methods, We evaluated ul trasound images of 18 post-mortem human renal arteries and cross-secti onal IVUS images of main renal arteries in five patients with renal ar tery stenosis (RAS) or essential hypertension. Results. In vitro studi es have shown that renal-artery images had three layers when the arter ies had fibrous intimal thickening and medial hypertrophy. Renal arter ies, in which the fibrous intima was not well developed, showed circum ferentially homogenous bright echoes. In patients with atherosclerotic RAS and essential hypertension, IVUS images showed hyperechoic areas in the renal arterial walls, probably due to atherosclerosis. Typical three-layered ultrasound appearance was not easily seen during in vivo studies. Conclusion. Our findings suggest that hyperechoic images can be a diagnostic clue of atherosclerosis However, in vitro results do not always correspond exactly to in vivo findings, and caution is need ed when findings from in vitro IVUS imaging studies are applied to in vivo studies.