Abstract 15108: Incremental Value of Quantitative and Qualitative CT Myocardial Perfusion Assessment in Combination With CT Coronary Angiography for Determination of Functionally Significant Coronary Artery Disease - Comparison with Fractional Flow Reserve
Background: CT coronary angiography (CTA) is increasingly used to detect coronary artery disease but is limited in assessing its functional significance. Myocardial perfusion can be qualitatively interpreted on CT (CTP) or quantified by the ratio of subendocardial and subepicardial attenuation namely the transmural perfusion ratio (TPR). Fractional flow reserve is an invasive method to assess the functional significance of coronary artery stenosis with a high index of accuracy.
Aim: To determine the incremental value of TPR and qualitative perfusion assessment when used in combination with CTA for determination of functionally significant coronary artery stenoses using FFR as reference standard.
Methods: 31 patients with chest pain referred for invasive angiography underwent FFR and CT assessment including CTA, CTP and TPR which were acquired using 320-row detector CT and prospective ECG-gating. FFR was determined in all major vessels and assumed 0.5 in vessels with ≥90% stenosis and 0.95 in smooth arteries. FFR ≤0.8 was considered to indicate significant stenosis (FFRSS). CTA and CTP images were assessed by consensus between two blinded observers. TPR <0.99 was used as threshold for abnormal perfusion.
Results: Significant stenosis was present in 54% of patients and 32% of vessels. The presence of ≥50% stenosis on CTA had a per-vessel sensitivity of 0.93, specificity 0.73, positive and negative predictive values (PPV & NPV) of 0.62 and 0.96. Combined CTA and TPR increased the specificity and PPV to 0.85 and 0.65 and decreased the sensitivity and NPV to 0.61 and 0.82. In comparison, combined CTA and qualitative perfusion assessment increased the specificity to 0.98 and PPV 0.95 with a sensitivity of 0.78 and 0.90. Per patient and vessel accuracy of CTA, combined CTA/TPR and CTA/CTP was 0.80 and 0.77, 0.76 and 0.77and 0.97 and 0.90.
Conclusion: Quantitative myocardial perfusion assessment using TPR in combination with CTA increased the specificity of CTA to detect functionally significant stenosis with no improvement on overall accuracy. On the contrary, the use of qualitative assessment in combination with CTA significantly increased specificity and overall accuracy in detecting FFR significant coronary stenosis.
- © 2011 by American Heart Association, Inc.