Larose E et al. (2005) Characterization of human atherosclerotic plaques by intravascular magnetic resonance imaging. Circulation 112: 2324–2331

There is currently a need for imaging techniques that can successfully detect the presence, prognosis and progress of atherosclerotic plaques, especially in deeper arteries. One such method, intravascular MRI (IVMRI), has shown promise in ex vivo models.

Larose and colleagues first validated IVMRI against histopathology in atherosclerotic arteries ex vivo. Lipid, fibrous and calcified components within the plaque were successfully differentiated with good sensitivity and selectivity by combined T1-weighted, moderate T2-weighted and proton-density-weighted imaging. Accurate assessment of plaque size was also achieved. The technique was then assessed by imaging the iliac arteries of 25 patients in vivo, and results were compared with intravascular ultrasound (IVUS). By use of IVMRI, inner and outer plaque boundaries were readily visualized in all plaques, including those with heavy calcification; the heterogeneous structure of the plaques was also detectable. By contrast, IVUS did not detect this heterogeneity and was unable to measure size in calcified plaques because of interference. Interobserver and intraobserver agreement was high for the determination of plaque composition using IVMRI, but was poor for IVUS.

With IVMRI, the composition and size of plaques within deep vessels such as the iliac artery can be reliably determined. The authors suggest that this information might prove useful in research into new therapies for plaque stabilization. Although further work is needed to improve the associated technology, IVMRI shows potential as an investigative and clinical tool in atherosclerosis.