Multimodality imaging of the ischemic right ventricle: an overview and proposal of a diagnostic algorithm.

Right ventricular (RV) involvement is frequently detected in patients presenting with acute left ventricular myocardial infarction. The ischemic right ventricle carries a dismal outcome by predisposing the heart to arrhythmic events and mechanical or hemodynamic complications. A comprehensive RV evaluation by multimodality imaging could guide clinical practice but has always been a conundrum for the imagers. Two-dimensional echocardiography is the best first-line tool due to its availability of bedside capabilities. More advanced imaging techniques provide a more comprehensive evaluation of the complex RV geometry but are mostly reserved for the post-acute setting. Three-dimensional echocardiography has improved the evaluation of RV volumes and function. The recent application of speckle-tracking echocardiography to the right ventricle appears promising, allowing the earlier detection of subtle RV dysfunction. Cardiac magnetic resonance imaging is considered the gold standard for the RV assessment. Cardiac multidetector computed tomography could be a reliable alternative. The aim of this review is to focus on the growing importance of multimodality imaging of the ischemic right ventricle and to propose a diagnostic algorithm, in order to reach a comprehensive assessment of this too frequently neglected chamber.

Ultra-low-dose CT for left atrium and pulmonary veins imaging using new model-based iterative reconstruction algorithm.

AIMS: To evaluate the feasibility of ultra-low-dose CT for left atrium and pulmonary veins using new model-based iterative reconstruction (MBIR) algorithm. METHODS AND RESULTS: Two hundred patients scheduled for catheter ablation were randomized into two groups: Group 1 (100 patients, Multidetector row CT (MDCT) with MBIR, no ECG triggering, tube voltage and tube current of 100 kV and 60 mA, respectively) and Group 2 [100 patients, MDCT with adaptive statistical iterative reconstruction algorithm (ASIR), no ECG triggering, and kV and mA tailored on patient BMI]. Image quality, CT attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of left atrium (LA) and pulmonary veins, and effective dose (ED) were evaluated for each exam and compared between two groups.No significant differences between groups in terms of population characteristics, cardiovascular risk factors, anatomical features, prevalence of persistent atrial fibrillation and image quality score. Statistically significant differences were found between Group 1 and Group 2 in mean attenuation, SNR, and CNR of LA. Significantly, lower values of noise were found in Group 1 versus Group 2. Group 1 showed a significantly lower mean ED in comparison with Group 2 (0.41 ± 0.04 versus 4.17 ± 2.7 mSv). CONCLUSION: The CT for LA and pulmonary veins imaging using MBIR is feasible and allows examinations with very low-radiation exposure without loss of image quality.

Feasibility and diagnostic accuracy of a low radiation exposure protocol for prospective ECG-triggering coronary MDCT angiography.

AIM: To compare the feasibility, accuracy, and effective radiation dose (ED) of multidetector computed tomography (MDCT) in the detection of coronary artery disease using a combined ED-saving strategy including prospective electrocardiogram (ECG) triggering with a short x-ray window and a body mass index (BMI)-adapted imaging protocol using adaptive statistical iterative reconstruction (ASIR; group 1), in comparison with a prospective ECG triggering strategy alone (group 2). MATERIALS AND METHODS: One hundred and seventy patients scheduled for invasive coronary angiography (ICA) were evaluated. Fourteen patients were not eligible for MDCT. The remaining 156 patients were randomized to group 1 (78 patients) and group 2 (78 patients). Eight and 11 patients in groups 1 and 2, respectively, were excluded after randomization because the patients' heart rates were >65 beats/min. MDCT images were assessed for feasibility, signal-to-noise ration (SNR), and contrast-to-noise ratio (CNR), accuracy in detection of coronary stenoses >50% versus ICA and for ED. RESULTS: The feasibility, SNR, CNR, accuracy in a segment-based and patient-based model were similar in both groups (97 versus 95%, 14.5 ± 3.9 versus 14.2 ± 4.1, 16 ± 4.6 versus 16.5 ± 4.4, 95 versus 94% and 97 versus 99%, respectively). The ED in group 1 was 72% lower than in group 2 (2.1 ± 1.2 versus 7.5 ± 1.8 mSv, respectively; p<0.01). CONCLUSIONS: The use of a multi-parametric ED saving protocol results in a significant reduction in ED without a negative impact on accuracy.