Characterisation of atherosclerotic plaque by spectral analysis of intravascular ultrasound: An in vitro methodology

Abstract

Raw 30-MHz intravascular ultrasound data have been captured from postmortem coronary arteries ( n = 4) to develop radio frequency analysis techniques for the characterisation of atherosclerotic plaque. Digitised data acquired from positions ( n = 8) within diseased sections of artery were compared with the corresponding histology and radiology. Scan-converted images were used to locate regions of interest (ROI = 33) within areas of known tissue composition: loose fibrotic tissue (LFT), dense fibrotic tissue (DFT) and calcium (CA). A range of parameters was extracted from the normalised power spectrum of each ROI within the bandwidth 17–42 MHz. Significant discrimination between LFT DFT and between LFT CA was provided by maximum power and spectral slope (dBMHz −1). However, the greatest discriminative power was given by the y-axis (0 Hz) intercept of the spectral slope: LFT DFT ( p = 0.001); LFT CA ( p = 0.0001); and DFT CA ( p = 0.089).