Table 4.
Influence of image quality and coronary arterial calcifications on recategorization.
| CT-FFR Values | Level of Observation | n | Image Quality | Calcium Burden | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| r CNR | 95% CI | p | r HU | 95% CI | p | r QIQ | 95% CI | p | r CAC | 95% CI | p | ||||
| Absolute | Patient | 109 | −0.059 | −0.241, 0.127 | 0.55 | −0.073 | −0.261, 0.120 | 0.45 | −0.064 | −0.208, 0.080 | 0.40 | 0.394 | 0.221, 0.542 | <0.001 | |
| Vessel | RCA | 109 | −0.032 | −0.223, 0.157 | 0.74 | −0.081 | −0.276, 0.121 | 0.41 | −0.127 | −0.283, 0.033 | 0.10 | 0.078 | −0.115, 0.264 | 0.42 | |
| LM | 109 | 0.173 | −0.038, 0.363 | 0.07 | 0.204 | −0.010, 0.396 | 0.03 | 0.004 | −0.178, 0.184 | 0.97 | 0.001 | −0.184, 0.192 | 1.00 | ||
| LAD | 109 | −0.122 | −0.311, 0.075 | 0.21 | −0.146 | −0.340, 0.059 | 0.13 | −0.094 | −0.246, 0.066 | 0.22 | 0.393 | 0.200, 0.553 | <0.001 | ||
| LCX | 109 | 0.090 | −0.102, 0.276 | 0.35 | 0.066 | −0.135, 0.260 | 0.50 | −0.026 | −0.175, 0.128 | 0.73 | 0.129 | −0.069, 0.311 | 0.18 | ||
| Categorized | Patient | 109 | 0.011 | −0.177, 0.199 | 0.91 | −0.040 | −0.226, 0.149 | 0.68 | 0.009 | −0.227, 0.243 | 0.94 | 0.133 | −0.057, 0.313 | 0.17 | |
| Vessel | RCA | 109 | 0.114 | −0.076, 0.296 | 0.24 | 0.218 | 0.031, 0.390 | 0.02 | −0.226 | −0.444, 0.016 | 0.05 | 0.013 | −0.176, 0.200 | 0.90 | |
| LAD | 109 | 0.118 | −0.071, 0.300 | 0.22 | 0.091 | −0.098, 0.275 | 0.35 | −0.019 | −0.249, 0.213 | 0.86 | 0.099 | −0.091, 0.282 | 0.31 | ||
| LCX | 109 | −0.020 | −0.207, 0.169 | 0.84 | -0.061 | −0.246, 0.129 | 0.53 | 0.139 | −0.131, 0.389 | 0.28 | 0.207 | 0.019, 0.380 | 0.03 | ||
Correlation of CNR, contrast opacification (measured in HU), qualitative image quality, or CAC with either absolute CT-FFR values or categorization into hemodynamically relevant CAD. The first p-value column (and 95% CI) corresponds to CNR, the second to HU, and the third to QIQ, while the fourth p-value column (and 95% CI) corresponds to CAC. All p-values are with respect to the null hypothesis that no correlation exists (correlation coefficient r = 0). p-values < 0.05 were considered statistically significant. Thresholds for significant CAD were ≥50% diameter for QCA and ≤0.80 for CT-FFR, respectively. The LM was excluded in categorized values because no recategorizations were observed in the cohort. CAC = coronary artery calcium score, CAD = coronary artery disease, CI = confidence interval; CNR = contrast-to-noise ratio; CT-FFR = CT-derived fractional flow reserve; HU = Hounsfield units; LAD = left anterior descending artery; LM = left main coronary artery; LCX = circumflex artery; QCA = quantitative coronary angiography; QIQ = qualitative image quality; RCA = right coronary artery.