Figure 3.

Correlation of MRI signal intensities and AHA plaque types of vessel wall view segments.

Notes: Gray bars, with VSOP; white bars, without VSOP. With the progression of AHA type 0–5B, there is a correlation with a decrease in relative MRI signal intensity in rabbits with VSOP (Kendall’s tau-b, −0.278; P < 0.01), and as well without VSOP (Kendall’s tau-b, −0.366; P < 0.01) reflecting an influence of calcification on MRI signal intensities. MRI signal intensities for advanced lesion types 4, 5A, and 5B were significantly lower for the vessel wall segments of rabbits with VSOP compared to the control without VSOP. AHA type 5C reflects a fibrotic stable type with no significant MRI signal decrease with VSOP. P-values given above the columns refer to the differences in relative MRI signal intensities compared with the next higher AHA type with VSOP (upper row) and without VSOP (lower row). The middle row provides P-values for differences in relative MRI signal intensities between groups with VSOP and without VSOP. There was no segment observed with lesion type 6 in the rabbit without VSOP injection.

Abbreviations: MRI, magnetic resonance imaging; AHA, American Heart Association; VSOP, very small superparamagnetic iron oxide particles.