Automatic lipid detection in human coronary atherosclerosis using spectroscopic intravascular photoacoustic imaging

Lipid content is a key factor in vulnerable atherosclerotic plaques that may lead to myocardial infarction. Intravascular photoacoustic (IVPA) imaging is a possible method to identify lipid content in the artery wall. We developed a method to automatically detect lipids in human coronary atherosclerosis using spectroscopic IVPA. In cross-sectional IVPA/intravascular ultrasound (IVUS) scans of fresh ex vivo human coronary arteries, we correlated the photoacoustic spectra to a reference lipid spectrum in the 1200 nm spectral range. Correlation coeffcients above a certain cut-off value indicated similarity between IVPA and reference lipid spectra. Automatically detected lipid areas exhibited good correspondence with the histological lipid stain of the same cross section.