Abstract 2145: Two and Three-Dimensional Ultrasound Visualization of Early Arterial Atheroma In Vivo Using Targeted Echogenic Immunoliposomes
Background: We have developed echogenic immunoliposomes (ELIP) for atheroma detection. This study aimed to demonstrate visualization of early atheroma using intravascular ultrasound (IVUS) and targeted ELIP. Three-dimensional reconstruction (3-DR) of two-dimensional (2-D) IVUS images may also provide improved atheroma visualization.
Methods: Atheroma was induced in arteries of Yucatan miniswine (n=4) by endothelial cell denudation followed by a 2-week high cholesterol diet. The contralateral arteries were left intact and served as controls (n=4). Anti-intercellular adhesion molecule-1 (ICAM) and generic gammaglobulin (IgG)-conjugated ELIP were prepared. Arteries were imaged using IVUS before and after ELIP injection. Images were digitized, manually traced, segmented, and placed in tomographic sequence for 3-DR. Atheroma brightness was compared using computer-assisted videodensitometry and reported as mean gray scale values (MGSV). Plaque volume (PV) was also quantified.
Results: Anti-ICAM-ELIP enhanced early atheroma (Figure⇓) with a MGSV of 151±12 (p<0.001 vs. baseline and control). There was no highlighting of atheroma with IgG-ELIP (MGSV=120±11; p=NS vs. baseline and control). Arterial 3-DR allowed visualization of the entire PV. The highlighted PV was greater with anti-ICAM-ELIP (PV=3.82±0.42 mm3; p<0.01 vs. baseline).
Conclusion: This study demonstrates specific highlighting of early atheroma in vivo using anti-ICAM-ELIP. 3-DR of 2-D IVUS images provides visualization of the entire highlighted PV. This novel methodology has potential to allow quantification of PV for serial and long-term atherosclerotic treatment studies.