Diagnostic accuracy of coronary opacification derived from coronary computed tomography angiography to detect ischemia: first validation versus single-photon emission computed tomography

Transluminal attenuation gradient derived from coronary CT angiography to predict ischemia in SPECT myocardial perfusion imaging: Effect of coronary cross-sectional area

BACKGROUND

Coronary computed tomography angiography (CCTA)-based transluminal attenuation gradient (TAG) was suggested to determine the functional significance of a stenosis. However, evidence that TAG acquired by wide-volume scanners can assess the hemodynamic significance of stenosis assessed by single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is lacking. Moreover, coronary cross-sectional area may influence TAG. Hence, we aimed at assessing the diagnostic value of TAG to predict ischemia in SPECT-MPI and the correlation between TAG and the transluminal cross-sectional area gradient (TCG).

METHODS

Patients undergoing CCTA and SPECT-MPI for suspected coronary artery disease were included. TAG and TCG were calculated measuring the mean vessel attenuation and the cross-sectional area along major coronary vessels at 5-mm intervals.

RESULTS

A total of 255 coronary arteries of 87 patients were included. TAG and TCG did not discriminate between coronary arteries with or without ischemia as assessed by SPECT-MPI (p = .44 and p = .25, respectively). The area under the curve to predict ischemia was not increased by adding TAG (0.88, 95% CI 0.83-0.92) or TCG (0.87, 95% CI 0.81-0.90) to CCTA alone (0.85, 95% CI 0.80-0.89). There was a significant correlation between TAG and TCG (r = 0.43; p < .001).

CONCLUSIONS

CCTA-derived TAG and TCG do not offer any value in predicting ischemia assessed by SPECT-MPI. TAG is partly affected by differences in the coronary luminal area.

The value of coronary computed tomography angiography in assessing the cardiac circulation of an outpatient-based population

To evaluate the perfusion of coronary circulation and its related factors and the difference in the peak filling times in aortic sinus and coronary sinus by coronary computed tomography angiography (CCTA).From January 1 to August 1, 2018, 61 outpatients with angina pectoris were recruited, completed a questionnaire about risk factors and underwent CCTA, which was also used to assess the stenosis of different coronary artery segments.The duration of circulation was 9.50 ± 2.43 seconds in patients with flat T wave, which was shorter than the duration in normal subjects (P = .021). However, other cardiovascular risk factors showed no effect on the duration of circulation. In addition, the duration of circulation was closely related to the peak filling time of coronary sinus [r(s) = 0.681]. We further divided the circulation time difference (delta) values into 3 levels (<6, 6-12, and ≥12 seconds).It showed that the circulation duration (Y) was associated with:Therefore, the cardiac circulation duration was negatively related to the degree of stenosis in the 1 diagonal and proximal LCA.It compensates for the inability of CCTA to assess circulation at rest simply by determining the peak filling time in the aortic sinus and the coronary sinus. Moderate cardiac microcirculation duration was related to a low incidence of clinical symptoms and electrocardiogram disorders, which was determined mainly by the diagonal and left circumflex branch 1 of LCA.

Coronary CT angiography-derived plaque quantification with artificial intelligence CT fractional flow reserve for the identification of lesion-specific ischemia

OBJECTIVES

We sought to investigate the diagnostic performance of coronary CT angiography (cCTA)-derived plaque markers combined with deep machine learning-based fractional flow reserve (CT-FFR) to identify lesion-specific ischemia using invasive FFR as the reference standard.

METHODS

Eighty-four patients (61 ± 10 years, 65% male) who had undergone cCTA followed by invasive FFR were included in this single-center retrospective, IRB-approved, HIPAA-compliant study. Various plaque markers were derived from cCTA using a semi-automatic software prototype and deep machine learning-based CT-FFR. The discriminatory value of plaque markers and CT-FFR to identify lesion-specific ischemia on a per-vessel basis was evaluated using invasive FFR as the reference standard.

RESULTS

One hundred three lesion-containing vessels were investigated. 32/103 lesions were hemodynamically significant by invasive FFR. In a multivariate analysis (adjusted for Framingham risk score), the following markers showed predictive value for lesion-specific ischemia (odds ratio [OR]): lesion length (OR 1.15, p = 0.037), non-calcified plaque volume (OR 1.02, p = 0.007), napkin-ring sign (OR 5.97, p = 0.014), and CT-FFR (OR 0.81, p < 0.0001). A receiver operating characteristics analysis showed the benefit of identifying plaque markers over cCTA stenosis grading alone, with AUCs increasing from 0.61 with ≥ 50% stenosis to 0.83 with addition of plaque markers to detect lesion-specific ischemia. Further incremental benefit was realized with the addition of CT-FFR (AUC 0.93).

CONCLUSION

Coronary CTA-derived plaque markers portend predictive value to identify lesion-specific ischemia when compared to cCTA stenosis grading alone. The addition of CT-FFR to plaque markers shows incremental discriminatory power.

KEY POINTS

• Coronary CT angiography (cCTA)-derived quantitative plaque markers of atherosclerosis portend high discriminatory power to identify lesion-specific ischemia. • Coronary CT angiography-derived fractional flow reserve (CT-FFR) shows superior diagnostic performance over cCTA alone in detecting lesion-specific ischemia. • A combination of plaque markers with CT-FFR provides incremental discriminatory value for detecting flow-limiting stenosis.