Abstract 2798: Fibrin-specific Spectral CT Molecular imaging Detects Ruptured Plaque without Calcium Interference
Background: Emerging development of Spectral CT is expected augment CT angiography by eliminating coronary calcium interference and detecting ruptured coronary plaque with k-edge distinctive molecular imaging agents.
Objective The goal of these experiments was to develop a new class of molecular imaging agents, fibrin-specific Spectral CT nanoparticle, to detect microthombus in ruptured atherosclerotic plaque.
Methods: A “soft-type” bismuth nanocolloid (BiNC) (200 nm) was developed for Spectral CT imaging. Fibrin-rich clots suspended in PBS in test tubes were targeted with Biotinylated BiNCs (n=3) or the control nanocolloids (n=1) using a fibrin-specific monoclonal antibody (NIB5F3). Spectral CT images were obtained and 3D reconstruction performed. In experiment 2, microthrombus deposits on human carotid artery endarterectomy (CEA) specimens were targeted with biotinylated BiNCs or control nanocolloids and imaged with Spectral CT.
Results: The first targeted spectral CT images were obtained uniformly for all BiNC treated clots; no signal was seen in the control. BiNC layer thickness was estimated to be ≤200 μm and the bismuth surface density was 3.5 mass%. In experiment 2, Spectral CT enhancement of the small fibrin deposits in the ruptured carotid plaque treated with BiNC (K-edge=90.5keV) was readily apparent, in contradistinction to the control CEA specimens, and easily differentiated from calcium attenuation (K-edge=4.03keV). As is typical of CT, poorly attenuating soft-tissue detail was lost (Figure⇓).
Conclusions: This study reports the first example of Spectral CT molecular imaging agents, which can detect ruptured plaque without Ca interference.