A Preliminary Study of Computed Tomography Coronary Angiography Within a Single Cardiac Cycle in Patients With Atrial Fibrillation Using 256-Row Detector Computed Tomography

Usefulness of second-generation motion correction algorithm in improving delineation and reducing motion artifact of coronary computed tomography angiography

BACKGROUND

The purpose of this study was to investigate the usefulness of second-generation intra-cycle motion correction algorithm (SnapShot Freeze 2, GE Healthcare, MC2) in improving the delineation and interpretability of coronary arteries in coronary computed tomography angiography (CCTA) compared to first-generation intra-cycle motion correction algorithm (SnapShot Freeze, GE Healthcare, MC1).

METHODS

Fifty consecutive patients with known or suspected coronary artery disease who underwent CCTA on a 256-slice CT scanner were retrospectively studied. CCTA were reconstructed with three different algorithms: no motion correction (NMC), MC1, and MC2. The delineation of coronary arteries on CCTA was qualitatively rated on a 5-point scale from 1 (nondiagnostic) to 5 (excellent) by two radiologists blinded to the reconstruction method and the patient information.

RESULTS

On a per-vessel basis, the delineation scores of coronary arteries were significantly higher on MC2 images compared to MC1 images (median [interquartile range], right coronary artery, 5.0 [4.5-5.0] vs 4.5 [4.0-5.0]; left anterior descending artery, 5.0 [4.5-5.0] vs 4.5 [3.5-5.0]; left circumflex artery, 5.0 [4.5-5.0] vs 4.5 [3.9-5.0]; all p ​< ​0.05). On a per-segment basis, for both 2 observers, the delineation scores on segment 1, 2, 8, 9, 10, 12 and 13 on MC2 images were significantly better than those on MC1 images (p ​< ​0.05). The percentage of interpretable segments (rated score 3 or greater) on NMC, MC1, and MC2 images was 90.5-91.9%, 97.4-97.9%, and 100.0%, respectively.

CONCLUSION

Second-generation intra-cycle motion correction algorithm improves the delineation and interpretability of coronary arteries in CCTA compared to first-generation algorithm.

A look at radiation detectors and their applications in medical imaging

The effectiveness and precision of disease diagnosis and treatment have increased, thanks to developments in clinical imaging over the past few decades. Science is developing and progressing steadily in imaging modalities, and effective outcomes are starting to show up as a result of the shorter scanning periods needed as well as the higher-resolution images generated. The choice of one clinical device over another is influenced by technical disparities among the equipment, such as detection medium, shorter scan time, patient comfort, cost-effectiveness, accessibility, greater sensitivity and specificity, and spatial resolution. Lately, computational algorithms, artificial intelligence (AI), in particular, have been incorporated with diagnostic and treatment techniques, including imaging systems. AI is a discipline comprised of multiple computational and mathematical models. Its applications aided in manipulating sophisticated data in imaging processes and increased imaging tests' accuracy and precision during diagnosis. Computed tomography (CT), positron emission tomography (PET), and Single Photon Emission Computed Tomography (SPECT) along with their corresponding radiation detectors have been reviewed in this study. This review will provide an in-depth explanation of the above-mentioned imaging modalities as well as the radiation detectors that are their essential components. From the early development of these medical instruments till now, various modifications and improvements have been done and more is yet to be established for better performance which calls for a necessity to capture the available information and record the gaps to be filled for better future advances.

Evaluation of the second-generation whole-heart motion correction algorithm (SSF2) used to demonstrate the aortic annulus on cardiac CT

The main purpose of pre-transcatheter aortic valve implantation (TAVI) cardiac computed tomography (CT) for patients with severe aortic stenosis is aortic annulus measurements. However, motion artifacts present a technical challenge because they can reduce the measurement accuracy of the aortic annulus. Therefore, we applied the recently developed second-generation whole-heart motion correction algorithm (SnapShot Freeze 2.0, SSF2) to pre-TAVI cardiac CT and investigated its clinical utility by stratified analysis of the patient's heart rate during scanning. We found that SSF2 reconstruction significantly reduced aortic annulus motion artifacts and improved the image quality and measurement accuracy compared to standard reconstruction, especially in patients with high heart rate or a 40% R-R interval (systolic phase). SSF2 may contribute to improving the measurement accuracy of the aortic annulus.

Adoption of Computed Tomography Image via Nano Contrast Agent in the Diagnosis and Treatment of Arrhythmia Patients

To explore the function and specific adoption of nano contrast agent in computed tomography (CT) images of patients with arrhythmia. In this study, the control group received general CT examination, and the test group received preoperative injection of nano contrast agent. All patients were scanned by retrospective electrocardiogram (ECG)-gated helical scanning, after which the coronary artery reconstruction and analysis were performed in a dedicated image post-processing workstation. Compared with the control group, there were decreases in heart rate variability, multistage reconstruction requirement, ECG editing requirement, and the undiagnosed segment ratio during CT scanning in the test group, while the proportion of diagnosable segments and diagnosable patients increased; the average duration of CT image postprocessing in the test group was higher than that in the control group. The nano contrast agent could improve the quality of CT images of some patients with arrhythmia, and the improvement was different in patients with different types of arrhythmia. The overall CT image quality and post-processing of patients with arrhythmia were improved by nano contrast agent, and this experiment laid a foundation for the clinical adoption of nano contrast agent in CT image detection and pointed out the direction for subsequent clinical research.

Computed tomography recent history and future perspectives

Purpose: We provide a review of the key computed tomography (CT) technologies developed since the late 1980s and offer an overview of one of the future technologies under development. The focus of this review is mainly on the hardware and system development. The topics on the historical event linked to the early days of CT development and other innovations that contributed to the CT development, such as advanced image reconstruction techniques, are covered by companion papers in this special issue. Approach: The review is divided into five major sections, each linked to a key innovation in CT: helical spiral data acquisition, multi-slice CT, wide-cone CT, dual-source CT, and spectral CT. Given the limited scope of this review, only one of the future technologies, photon-counting CT, is discussed in detail. Whenever possible, both theory of operation and clinical examples are provided. Results: Theoretical analyses, phantom results, and clinical examples clearly demonstrate the efficacy and clinical relevancy of five historical technology developments and one future technology in CT. These technologies have improved and will continue to improve CT performance in terms of isotropic volume coverage, improved temporal resolution, and material differentiation and characterization capabilities. Conclusions: Over the past 30 years, technological developments of CT have contributed to the success of CT in many clinical applications such as trauma, oncology, cardiac imaging, and stroke. Advanced clinical applications have and will continue to demand more advanced technology development.

Can the Coronary Artery Calcium Score Scan Reduce the Radiation Dose in Coronary Computed Tomography Angiography?

RATIONALE AND OBJECTIVES

Radiation exposure from coronary computed tomography angiography (CCTA) remains a cause for concern. The objective of this study was to investigate whether using the coronary artery calcium score scan (CACS) would reduce the radiation dose for CCTA scanning and the overall radiation exposure (ORE).

MATERIALS AND METHODS

In total, 256 patients were examined with a third-generation dual-source CT (n = 200) or 256-row CT (n = 56), among whom 105 (Group A) and 28 patients (Group B), respectively, underwent CCTA with CACS for field of view planning. The remaining patients, with the scout view for field of view planning, constituted Group A1 and B1. The scanning parameter settings were standardized between groups.

RESULTS

Shorter scan lengths were observed in Group A (9.98 ± 0.79 cm) compared to Group A1 (13.64 ± 1.79 cm; p < 0.001), which also resulted in a lower dose-length product (DLP) in Group A (115.04 ± 64.13) relative to Group A1 (138.67 ± 68.87; p < 0.05). Similarly, shorter scan lengths were found in Group B (14.92 ± 1.17 cm) compared to Group B1 (15.79 ± 0.63 cm; p = 0.001); this resulted in a lower DLP (322.07 ± 45.39) compared to Group B1 (354.34 ± 65.27; p = 0.036). The CACS resulted in an increase in ORE in both groups.

CONCLUSION

CACS may have a critical role in the reduction of radiation dose in CCTA scanning, but the potential effectiveness of CACS in reducing ORE is weak.

Left Atrial Appendage Mechanical Exclusion: Procedural Planning Using Cardiovascular Computed Tomographic Angiography

Left atrial appendage (LAA) mechanical exclusion is being investigated for nonpharmacologic stroke risk reduction in selected patients with atrial fibrillation. There are multiple potential approaches in various stages of development and clinical application, each of which depends on specific cardiothoracic anatomic characteristics for optimal performance. Multiple imaging modalities can be utilized for application of this technology, with transesophageal echocardiography used for intraprocedural guidance. Cardiovascular computed tomographic angiography can act as a virtual patient avatar, allowing for the assessment of cardiac structures in the context of surrounding cardiac, coronary vascular, thoracic vascular, and visceral and skeletal anatomy, aiding preprocedural decision-making, planning, and follow-up. Although transesophageal echocardiography is used for intraprocedural guidance, computed tomographic angiography may be a useful adjunct for preprocedure assessment of LAA sizing and anatomic obstacles or contraindications to deployment, aiding in the assessment of optimal approaches. Potential approaches to LAA exclusion include endovascular occlusion, epicardial ligation, primary minimally invasive intercostal thoracotomy with thoracoscopic LAA ligation or appendectomy, and minimally invasive or open closure as part of cardiothoracic surgery for other indications. The goals of these procedures are complete isolation or exclusion of the entire appendage without leaving a residual appendage stump or residual flow with avoidance of acute or chronic damage to surrounding cardiovascular structures. The cardiovascular imager plays an important role in the preprocedural and postprocedural assessment of the patient undergoing LAA exclusion.

Qualitative and quantitative image analysis of 16 cm wide-coverage computed tomography compared to new-generation dual-source CT

BACKGROUND

Diagnostic quality of computed tomography (CT) images depends on numerous factors. Recently, two different modalities were introduced for coronary CT angiography (CCTA).

OBJECTIVE

This study aims to compare the performance of 16 cm wide-coverage detector CT (WDCT) using the snapshot freeze technique with a new-generation dual-source CT (DSCT) with 66 ms temporal resolution for CCTA.

METHODS

Total 101 patients with suspected coronary heart disease were enrolled. Of these, 50 and 51 patients were examined on WDCT and DSCT, respectively. CT values, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured. The image processing efficiency was recorded, followed by statistical comparison of diagnostic accuracy and radiation dose.

RESULTS

Ninety-nine patients (98.02%) had satisfactory diagnostic image quality. DSCT was significantly better than WDCT in terms of quantitative image quality, image processing efficiency, and qualitative analysis (P < 0.05). However, radiation dose was significantly lower on WDCT (P < 0.05) as compared to DSCT.

CONCLUSIONS

Image processing efficiency and image quality of CCTA was higher on DSCT compared to WDCT due to the limitation of maximal tube current of WDCT.

Diagnostic accuracy of computed tomography coronary angiography utilizing recent advances in technology in patients with high heart rates: a systematic review protocol

OBJECTIVE

The objective of this review is to determine the diagnostic accuracy of computed tomography coronary angiography (CTCA) using recent scan technologies for detecting coronary artery disease (CAD) in adults with high heart rates.

INTRODUCTION

Invasive coronary angiography is the gold standard for detecting significant CAD, but it is costly and carries risks of complications. Computed tomography coronary angiography has a high sensitivity for diagnosing CAD, although image quality may be affected by elevated heart rates. Recent technological advances in scanner design may increase the diagnostic accuracy of CTCA.

INCLUSION CRITERIA

This review will consider diagnostic test accuracy studies that include adults 18 years and older with a heart rate greater than 65 beats per minute who have undergone CTCA to diagnose CAD (greater than 50% stenosis). Eligible studies will compare invasive coronary angiography with computed tomography scanner technologies that use either single- or dual-source scanner configuration in prospective electrocardiogram scan acquisition mode, and with a total scanner coverage equal to or greater than 128 detector-rows. Studies published in English from 2007 will be considered.

METHODS

PubMed, Embase, CINAHL and Scopus will be searched, along with Google Scholar, the NIHR-HTA register, computed tomography vendors and conference abstracts. Screening of potential titles and abstracts, retrieval of full-text studies, assessment of methodological quality and data extraction will be performed independently by two reviewers. Meta-analyses will be performed, if possible, and a Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Summary of Findings presented.