Computed tomography to diagnose coronary artery disease: A reduction in radiation dose increases applicability

Application of prospective ECG-gated multiphase scanning for coronary CT in children with different heart rates

BACKGROUND

To investigate the application of prospective ECG-gated multiphase scanning in coronary CT imaging in children with different heart rates.

METHODS

In the control group, 160 children aged 2-4 years who underwent a coronary CT examination in our hospital from May 2016 to December 2017 were retrospectively selected. They were divided into five subgroups according to their heart rate frequency: 75-85 beats/min, 86-95 beats/min, 96-105 beats/min, and 106-120 beats/min. There were 40 children in each subgroup. Each child was treated with retrospective ECG-gated scanning technology. Six groups of phase images were reconstructed: 40%, 45%, 50%, 70%, 75% and 80%. The optimal phase was selected for coronary artery reconstruction. In the study group, 240 children aged 2-4 years who underwent coronary artery CT examination in our hospital from January 2018 to May 2019 were prospectively selected and divided into five subgroups according to the heart rate frequency: 75-85 beats/min, 86-95 beats/min, 96-105 beats/min, and 106-120 beats/min. There were 60 children in each subgroup. A prospective ECG-gated multiphase scanning technique was used to reconstruct 70%, 75% and 80% phase images in the subgroups with heart rates < 85/min. In the remaining subgroups, 40%, 45% and 50% phase images were reconstructed, and the optimal phase was selected for coronary artery reconstruction. The scanning parameters, dosage of contrast medium and injection mode of contrast medium were the same in both groups. The radiation dose and image quality of the coronary artery were compared between the two groups at the same heart rate.

RESULTS

When comparing the two groups at the same heart rate, the radiation dose in the study group was 72% lower than that in the control group (P < 0.05). There was no significant difference in coronary artery image quality between the two groups at the optimal phase (P > 0.05).

CONCLUSIONS

Applying prospective ECG-gated multiphase scanning technology to children's coronary CT imaging can significantly reduce the scanning radiation dose without affecting the quality of the coronary artery image.

Clinical impact of low-radiation computed tomography coronary angiography diagnosis for coronary artery stenosis: Study Protocol

BACKGROUND

The objective of this study aims to assess the clinic impact of low-radiation computed tomography coronary angiography (LR-CTCA) diagnosis for coronary artery stenosis (CAS).

METHODS

This study will comprehensively search the following electronic databases from inception to the present: PUBMED, EMBASE, Cochrane Library, PsycINFO, Web of Science, Google, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, VIP database, WANGFANG, and China National Knowledge Infrastructure. All these electronic databases will be searched without language restrictions. All case-controlled studies on assessing the clinical impact of LR-CTCA diagnosis for patients with CAS will be included. Quality Assessment of Diagnostic Accuracy Studies tool will be utilized to evaluate the methodological quality for each qualified studies.

RESULTS

We will assess the clinic impact of LR-CTCA diagnosis for CAS by measuring sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio.

CONCLUSION

The results of this study will summarize the latest evidence of LR-CTCA diagnosis for CAS.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019139336.

Utility of Multimodality Imaging in the Morphologic Characterization of Anomalous Aortic Origin of a Coronary Artery

Background:

Anomalous aortic origin of a coronary artery from the wrong Sinus of Valsalva (AAOCA) is a rare congenital anomaly and is associated with sudden cardiac death. Morphologic features considered to be “high risk” are significant luminal narrowing, acute coronary angulation at its origin, intramural course, and long interarterial course. A consistent approach for characterization of these features is lacking.

Methods:

A retrospective single-center review of all patients diagnosed with AAOCA using echocardiogram and computed tomography (CT)/magnetic resonance imaging (MRI) studies was performed. Twenty-nine patients were identified (25 using CT and 4 using MRI) with subsequent three-dimensional data sets. The MRI data sets lacked adequate resolution and were excluded. Twenty-five patients (median age 15.1, range 10-39.5 years, 72% male) were further analyzed using echocardiogram and CT. Morphologic assessment focused on luminal stenosis, coronary angulation, and interarterial length. Additional morphologic features focusing on cross-sectional area and degree of ellipticity were also assessed.

Results:

Echocardiography tended to yield smaller measurements compared to CT and had poor interobserver reproducibility for measurements pertaining to the narrowest proximal and distal coronary segments. Computed tomography showed good inter-/intraobserver reproducibility for the same. Agreement between both modalities for coronary angulation at its origin was excellent. There was good agreement for measurements of interarterial length between echocardiography and CT, but echocardiography had superior reproducibility. Assessment of luminal cross-sectional area and elliptical shape by CT had excellent inter-/intraobserver reproducibility.

Conclusion:

The combination of echocardiography and CT characterizes morphologic features of anomalous origin of the coronary artery more reliably than either modality alone.

Assessment of the myocardium with cardiac computed tomography

The imaging of myocardial disease is of increasing importance for cardiologists from all subspecialties, for diagnosis, risk stratification, or to facilitate therapy. While the gold standard modalities for such assessment are cardiac magnetic resonance and echocardiography, these are not universally suitable. Cardiac computed tomography (CT), well-established for the assessment of coronary artery disease (CAD), can be of value in the assessment of myocardial pathology, due to excellent patient compatibility and tolerability, high spatial resolution, and acceptable tissue characterization. This review considers the value and limitations of CT in the assessment of the myocardial sequelae of CAD, and for patients with a variety of other cardiomyopathic diseases, depicts some of the common findings, and considers current developments in this area.