Computed tomography versus near-infrared spectroscopy for the assessment of coronary atherosclerosis.

Background: Coronary computed tomography angiography (CCTA) has been proposed as an alternative to intravascular imaging for assessing plaque pathology.

Aims: We aimed to assess the efficacy of CCTA against near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) in evaluating atheroma burden and composition and for guiding coronary interventions.

Methods: Seventy patients with a chronic coronary syndrome were recruited and underwent CCTA and NIRS-IVUS. The imaging data were matched, and the estimations of lumen, vessel wall and plaque dimensions and composition of the two modalities were compared. The primary endpoint of the study was the efficacy of CCTA in detecting lipid-rich plaques identified by NIRS-IVUS. Secondary endpoints included the performance of CCTA in evaluating coronary artery pathology in the studied segments and its value in stent sizing, using NIRS-IVUS as the reference standard.

Results: In total, 186 vessels were analysed. The attenuated plaque volume on CCTA had weak accuracy in detecting lipid-rich plaques (58%; p=0.029). Compared to NIRS-IVUS, CCTA underestimated the lumen volume (309.2 mm³ vs 420.4 mm³; p=0.001) and plaque dimensions (total atheroma volume 116.1 mm³ vs 292.8 mm³; p<0.001 and percentage atheroma volume 27.67% vs 41.06%; p<0.001) and overestimated the lipid component (lipid core burden index 48.6 vs 33.8; p=0.007). In the 86 lesions considered for revascularisation, CCTA underestimated the reference vessel area (8.16 mm² vs 12.30 mm²; p<0.001) and overestimated the lesion length (23.5 mm vs 19.0 mm; p=0.029) compared to NIRS-IVUS.

Conclusions: CCTA has limited efficacy in assessing plaque composition and quantifying lumen and plaque dimensions and tissue types, which may potentially impact revascularisation planning.