Mid-infrared reflectivity of experimental atheromas.

We report that the pathologic components present within the atheromatous plaques of ApoE knock-out mice can reflect significant amounts of mid-infrared (mid-IR) light. Furthermore, the reflected light spectra contained the unique signatures of a variety of biologic features including those found in unstable or "vulnerable" plaque. This discovery may represent a unique opportunity to develop a new intravascular diagnostic modality that can detect and characterize sites of atherosclerosis.