Arterial imaging: comparison of high-resolution US and MR imaging with histologic correlation.

The potential roles of intravascular ultrasound (US) and magnetic resonance (MR) imaging in evaluating the artery wall and atherosclerotic plaque were compared. Excised human femoral and carotid arteries were imaged with a 42-MHz intravascular US system and a 1.5-T MR imager equipped with enhanced gradients. In-plane resolution was 40-280 microns for US and 156 microns for MR imaging. Stained histologic tissue sections were obtained for correlation with the imaging findings. Intravascular US and MR imaging both had sufficient resolution and contrast to demonstrate arterial layers and allow distinction of atheroma. Correspondence between structures identified with the two modalities was excellent and in agreement with histologically defined arterial structures. Findings on state-of-the-art intravascular US and MR images correlate well with histologic findings in normal and diseased arteries. Intravascular US has the advantages of speed and resolution, whereas MR imaging demonstrates superior contrast in the depiction of atheroma.