Abstract
BackgroundThe aim of this study was to investigate the correlation of the qualitative transmural extent of hypoperfusion areas (HPA) using stress dynamic whole-heart computed tomography perfusion (CTP) imaging by 256-slice CT with CTP-derived myocardial blood flow (MBF) for the estimation of the severity of coronary artery stenosis.Methods and ResultsEleven patients underwent adenosine triphosphate (0.16 mg/kg/min, 5 min) stress dynamic CTP by 256-slice CT (coverage: 8 cm, 0.27 s/rotation), and 9 of the 11 patients underwent coronary angiography (CAG). Stress dynamic CTP (whole–heart datasets over 30 consecutive heart beats in systole without spatial and temporal gaps) was acquired with prospective ECG gating (effective radiation dose: 10.4 mSv). The extent of HPAs was visually graded using a 3-point score (normal, subendocardial, transmural). MBF (ml/100g/min) was measured by deconvolution. Differences in MBF (mean ± standard error) according to HPA and CAG results were evaluated. In 27 regions (3 major coronary territories in 9 patients), 11 coronary stenoses (> 50% reduction in diameter) were observed. In 353 myocardial segments, HPA was significantly related to MBF (P < 0.05; normal 295 ± 94; subendocardial 186 ± 67; and transmural 80 ± 53). Coronary territory analysis revealed a significant relationship between coronary stenosis severity and MBF (P < 0.05; non-significant stenosis [< 50%], 284 ± 97; moderate stenosis [50–70%], 184 ± 74; and severe stenosis [> 70%], 119 ± 69).ConclusionThe qualitative transmural extent of HPA using stress whole-heart dynamic CTP imaging by 256-slice CT exhibits a good correlation with quantitative CTP-derived MBF and may aid in assessing the hemodynamic significance of coronary artery disease.
Highlights
Recent technical advancements in multi-detector row computed tomography (MDCT) have enabled coronary CT angiography to become a preferred noninvasive technique to assess coronary artery stenosis [1,2] and atherosclerotic plaque [3,4] in patients with coronary artery disease (CAD).Myocardial perfusion abnormality, which is the first step in the ischemic cascade, has been evaluated with nuclear medicine [5,6,7,8], magnetic resonance (MR) imaging [9,10], and echocardiography [11] for risk stratification of myocardial ischemia
In 2 of 13 patients, whole-heart dynamic stress computed tomography perfusion (CTP) data could not be acquired, because their heart position was slightly deviated from the coverage of the 256-slice MDCT; in the remaining 11 patients, whole-heart dynamic series of contiguous short-axis views were successfully acquired and evaluated with neither spatial nor temporal gaps (Figures 1, 2)
Because stress dynamic CTP imaging had insufficient coverage in 2 patients, and no coronary stenosis on coronary CTA was found in 2 other patients, 9 patients underwent coronary angiography (CAG) and were included in the analysis
Summary
Recent technical advancements in multi-detector row computed tomography (MDCT) have enabled coronary CT angiography (coronary CTA) to become a preferred noninvasive technique to assess coronary artery stenosis [1,2] and atherosclerotic plaque [3,4] in patients with coronary artery disease (CAD).Myocardial perfusion abnormality, which is the first step in the ischemic cascade, has been evaluated with nuclear medicine [5,6,7,8], magnetic resonance (MR) imaging [9,10], and echocardiography [11] for risk stratification of myocardial ischemia. Single-phase first-pass CTP imaging by retrospective or prospective electrocardiogram (ECG) gated acquisition allows us to evaluate qualitative methods such as CT attenuation based hypoperfusion areas (HPA) [12,13,14,15], and dynamic CTP imaging enables us to estimate quantitative parameters such as myocardial blood flow (MBF) [16,17,18,19]. The aim of this study was to investigate the correlation of the qualitative transmural extent of hypoperfusion areas (HPA) using stress dynamic whole-heart computed tomography perfusion (CTP) imaging by 256-slice CT with CTP-derived myocardial blood flow (MBF) for the estimation of the severity of coronary artery stenosis. Conclusion: The qualitative transmural extent of HPA using stress whole-heart dynamic CTP imaging by 256-slice CT exhibits a good correlation with quantitative CTP-derived MBF and may aid in assessing the hemodynamic significance of coronary artery disease
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