Evaluation of chronic ischemic heart disease with myocardial perfusion and regional contraction analysis by contrast-enhanced 256-MSCT

Effect of heart rate on the diagnostic accuracy of 256-slice computed tomography angiography in the detection of coronary artery stenosis: ROC curve analysis

The aim of the present study was to investigate the effect of heart rate (HR) on the diagnostic accuracy of 256-slice computed tomography angiography (CTA) in the detection of coronary artery stenosis. Coronary imaging was performed using a Philips 256-slice spiral CT, and receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic value of 256-slice CTA in coronary artery stenosis. The HR of the research subjects in the study was within a certain range (39-107 bpm). One hundred patients suspected of coronary heart disease underwent 256-slice CTA examination. The cases were divided into three groups: Low HR (HR <75 bpm), moderate HR (75≤ HR <90 bpm) and high HR (HR ≥90 bpm). For the three groups, two observers independently assessed the image quality for all coronary segments on a four-point ordinal scale. An image quality of grades 1-3 was considered diagnostic, while grade 4 was non-diagnostic. A total of 97.76% of the images were diagnostic in the low-HR group, 96.86% in the moderate-HR group and 95.80% in the high-HR group. According to the ROC curve analysis, the specificity of CTA in diagnosing coronary artery stenosis was 98.40, 96.00 and 97.60% in the low-, moderate- and high-HR groups, respectively. In conclusion, 256-slice coronary CTA can be used to clearly show the main segments of the coronary artery and to effectively diagnose coronary artery stenosis. Within the range of HRs investigated, HR was found to have no significant effect on the diagnostic accuracy of 256-slice coronary CTA for coronary artery stenosis.

Semi-quantitative myocardial perfusion measured by computed tomography in patients with refractory angina: a head-to-head comparison with quantitative rubidium-82 positron emission tomography as reference

INTRODUCTION

Computed tomography (CT) is a novel method for assessment of myocardial perfusion and has not yet been compared to rubidium-82 positron emission tomography (PET). We aimed to compare CT measured semi-quantitative myocardial perfusion with absolute quantified myocardial perfusion using PET and to detect stenotic territories in patients with severe coronary artery disease.

MATERIALS AND METHODS

Eighteen patients with stenosis narrowing coronary arteries ≥70% demonstrated on invasive coronary angiography underwent rest and adenosine stress imaging obtained by 320-multidetector CT scanner and CT/PET 64-slice scanner. CT measured myocardial attenuation density (AD) and perfusion index (PI) were correlated to absolute PET myocardial perfusion values.

RESULTS

Rest AD, rest and stress PI did not correlate to PET findings (r = 0·412, P = 0·113; r = 0·300, P = 0·259; and r = 0·508, P = 0·064, respectively). However, there was a significant correlation between stress AD and stress PET values (r = 0·670, P = 0·009) and between stress and rest differences for AD and PI with PET differences (r = 0·620, P = 0·006; and r = 0·639, P = 0·004, respectively). Furthermore, significant differences were observed between remote and stenotic territories for rest and stress AD (48 ± 14HU and 37 ± 16HU, P = 0·002; 76 ± 19HU and 58 ± 13HU, P<0·001, respectively), PI (9·6 ± 2·9 and 7·5 ± 3·1, P = 0·002; 21·6 ± 4·1 and 16·9 ± 3·9, P<0·001, respectively) and PET (0·96 ± 0·37 ml g^-1  min^-1 and 0·86 ± 0·26 ml g^-1  min^-1 , P = 0·036; 2·07 ± 0·76 ml g^-1  min^-1 and 1·61 ± 0·76 ml g^-1  min^-1 , P = 0·006, respectively).

CONCLUSIONS

Semi-quantitative CT parameters may be useful in the detection of myocardium subtended by stenotic coronary arteries.

Revascularization in heart failure in the post-STICH era

Left ventricular (LV) dysfunction caused by ischemia secondary to coronary artery disease results not only from cardiac myocyte death but also from stunning and hibernation, which are potentially reversible phenomena. Myocardial viability testing is often used in patients with ischemic cardiomyopathy to predict recovery of contractile function after revascularization. Although several observational studies have supported the use of viability testing, the Surgical Treatment for Ischemic Heart failure (STICH) viability substudy challenged its role in clinical decision-making, as viability testing in this study did not predict differential outcomes based on treatment type, and there was a trend toward increased survival in patients with no viability who underwent revascularization. However, the results of the STICH trial have caused controversy because of limitations in study design and implementation. Randomized controlled trials using high-resolution modalities such as positron emission tomography or delayed hyperenhancement cardiac magnetic resonance are needed to determine the incremental benefits that revascularization may afford based on myocardial viability.