INTRAVASCULAR ULTRASOUND AND MAGNETIC-RESONANCE-IMAGING IN THE ASSESSMENT OF ATHEROSCLEROTIC LESIONS IN RABBIT AORTA - CORRELATION TO HISTOPATHOLOGIC FINDINGS

RATIONALE AND OBJECTIVES. The authors compare the usefulness of intrav ascular ultrasound (IVUS) and magnetic resonance imaging (MRI) for qua ntitation of atherosclerosis in hyperlipidemic rabbits, correlated wit h histopathology, METHODS. Magnetic resonance imaging with T1- and T2- weighted spin echo sequences and three-dimensional time-of-flight MR a ngiography of the abdominal aorta was performed on seven rabbits using a 1.5 T MR imager and a standard head coil. X-ray angiography and IVU S examination (3.5 F/30 MHz imaging catheter) was performed via caroti d artery access. RESULTS. Time-of-flight MR angiography source images provided the best resolution and plaque-lumen contrast in visual compa rison between the different MRI sequences. Intra- and interobserver re producibilities of the lesion thickness and area measurements were sim ilar in IVUS and MRI (Pearson correlations 0.52-0.97; P < 0.01), The m easurements from IVUS and MRI correlated closely with each other as we ll as with those made from histopathologic specimens (Pearson correlat ions 0.50-0.79; P < 0.001), The measurements from IVUS were somewhat m ore accurate than those made from MRI, CONCLUSIONS. Both MRI and IVUS with clinically available imaging equipments are feasible and accurate for the quantitation of experimental atherosclerosis of rabbit aorta.