Imaging Modalities to Identity Inflammation in an Atherosclerotic Plaque

Table 1

Noninvasive imaging modalities to detect a vulnerable plaque.

Noninvasive imaging technique	Spatial resolution	Plaque characteristic identified	Advantages	Limitations
CT	50 micron	Plaque morphology (eccentric pattern, outward remodelling, and spotty calcifications), coronary plaque burden, cap thickness, and macrophages (N1177-specific contrast agent)	High spatial and temporal resolution, real time, quite fast, operator-independent, and excellent calcium detection	Radiation exposure, contrast, difficult to distinguish thrombus, blooming artefacts by calcium, and claustrophobia
MRI	10–100 micron	Plaque morphology, plaque composition, lipid-rich necrotic core, intraplaque haemorrhage, neoangiogenesis, macrophages, flow measurement, and quantification of stenosis	No radiation, high soft tissue contrast, can be repeated over time, functional, operator-independent, with or without contrast, and many plaque components detected	Low resolution, system fibrosis due to contrast agent, time-consuming, metal implants contraindicated, claustrophobia, cardiac motion artefact, and limited spatial resolution
Ultrasound	50 micron	Plaque morphology, intima media thickness, flow velocities, and neoangiogenesis (contrast US)	High temporal resolution, cheap, easy to use, no radiation, bedside/large availability, fastest, and functional	Limited sensitivity and specificity, interobserver variability, calcium and air artefacts, limited spatial resolution, and penetration
PET	1-2 millimeters	Plaque inflammation, macrophages, and neoangiogenesis	High sensitivity and specific targets are detected	Limited resolution, radiation exposure, expensive, limited availability, myocardial uptake of FDG, and cardiac motion artefact
SPECT	0.3–1 millimeters	Plaque inflammation, apoptosis, lipoprotein accumulation, chemotaxis, angiogenesis, proteolysis, and thrombogenicity.	High sensitivity, low cost, and more spatial resolution as compared with PET	Limited resolution, nonspecificity, radiation exposure, limited availability, and cardiac motion artefact

CT, computed tomography; MRI, magnetic resonance imaging; US, ultrasound; PET, positron emission tomography; SPECT, single positron emission computed tomography.