Table 1: Similarities and differences IVUS-based imaging modalities.

	VH	IMAP	Integrated backscatter
Backscatter radiofrequency signal analysis	Autoregressive model	Fast Fourier transformation	Fast Fourier transformation
Colour code	Fibrous: green Fibrofatty: light green Necrotic core: red Dense calcium: white	Fibrotic: light green Lipidic: yellow Necrotic: pink Calcified: blue	Fibrosis: light green Dense fibrosis: yellow Lipid: blue Calcified: red
Ex vivo Validation against histology	The overall predictive accuracies were 93.5 % for fibrous, 94.1 % for fibro-fatty, 95.8 % for necrotic core, and 96.7 % for dense calcium regions with sensitivities and specificities ranging from 72 % to 99 %[36]	The accuracies at the highest level of confidence (75-100%) were 95 % for fibrotic, 98 % for lipidic, 97 % for necrotic, and 98 % for calcified regions[25]	The sensitivity was 100 % for calcification, 94 % for fibrosis, and 84 % for lipid pool. The specificity was 99 % for calcification, 93 % for fibrosis, and 67 % for lipid pool[37]
In vivo validation of vulnerable plaque	The diagnostic accuracy to detect TCFA as determined by optical coherence tomography was 86 % with sensitivity 89 %, specificity 86 %[38]
Limitations	Acoustic shadowing behind the calcified tissue is expressed as fibrous of fibrofatty tissue VH shows external elastic membrane as a grey media stripe VH misclassifies stent struts as calcification with or without necrotic core Thrombus may be misclassified as fibrous or fibrofatty plaque	Acoustic shadowing behind the calcified tissue and the wire artifact is expressed as necrotic tissue Metallic stent struts appear as dense calcium without necrotic core	It cannot show plaque composition behind a severe calcification and guidewire It does not have the signal profile of metallic stent struts Intimal hyperplasia and lipid pool have similar IB values