Computer-Aided Image Analysis Algorithm to Enhance In Vivo Diagnosis of Plaque Erosion by Intravascular Optical Coherence Tomography
Background—Recent reports show that plaque erosion can be diagnosed in vivo using optical coherence tomography (OCT) in patients with acute coronary syndromes (ACS). However, quantitative OCT image criteria for computer-aided diagnosis of plaque erosion have not been established.
Methods and Results—A total of 42 patients with ACS caused by plaque erosion were included. Plaque erosion was identified according to the previously established OCT criteria. Both optical properties and morphological features of the focal eroded region as well as erosion-adjacent region were analyzed using a custom designed computer algorithm. Non-eroded fibrous plaques remote from the erosion site within the same vessel were used as controls. Compared to control plaques, eroded plaques have significantly lower surface intensity (p<0.001), lower region of interest (ROI) intensity (p<0.001), lower surface normalized standard deviation (NSD) (p<0.001), lower ROI NSD (p<0.001), higher optical attenuation (p<0.001), larger tissue protrusion area (p<0.001) and greater surface roughness (p<0.001). Erosion-adjacent regions also have lower ROI NSD (p=0.008), higher attenuation (p<0.001), and greater surface roughness (p=0.005). Using a logistic regression model built upon the quantitative features, plaque erosion can be accurately classified against intact fibrous plaques. There was low inter- and intra-observer variability associated with the algorithm-assisted quantitative assessment.
Conclusions—Plaque erosion has distinctive optical properties and morphological features compared to non-eroded fibrous plaques. Quantitative image analysis may enhance diagnostic accuracy for plaque erosion in vivo.
- Received January 14, 2014.
- Accepted July 8, 2014.