Coronary artery visibility in free-breathing young children on non-gated chest CT: impact of temporal resolution

Efficacy and safety of coronary computed tomography angiography in diagnosing coronary lesions in children

INTRODUCTION

Identification of paediatric coronary artery abnormalities is challenging. We studied whether coronary artery CT angiography can be performed safely and reliably in children.

MATERIALS

Retrospective analysis of consecutive coronary CT angiography scans was performed for image quality and estimated radiation dose. Both factors were assessed for correlation with electrocardiographic-gating technique that was protocoled on a case-by-case basis, radiation exposure parameters, image noise artefact parameters, heart rate, and heart rate variability.

RESULTS

Sixty scans were evaluated, of which 96.5% were diagnostic for main left and right coronaries and 91.3% were considered diagnostic for complete coronary arteries. Subjective image quality correlated significantly with lower heart rate, increasing patient age, and higher signal-to-noise ratio. Estimated radiation dose only correlated significantly with choice of electrocardiographic-gating technique with median doses as follows: 2.42 mSv for electrocardiographic-gating triggered high-pitch spiral technique, 5.37 mSv for prospectively triggered axial sequential technique, 3.92 mSv for retrospectively gated technique, and 5.64 mSv for studies which required multiple runs. Two scans were excluded for injection failure and one for protocol outside the study scope. Five non-diagnostic cases were attributed to breathing motion, scanning prior to peak contrast enhancement, or scan acquisition during the incorrect portion of the R-R interval.

CONCLUSIONS

Diagnostic-quality coronary CT angiography can be performed reliably with a low estimated radiation exposure by tailoring each scan protocol to the patient's body habitus and heart rate. We propose coronary CT angiography is a safe and effective diagnostic modality for coronary artery abnormalities in children.

Childhood Interstitial Lung Disease: Imaging Guidelines and Recommendations

Childhood interstitial lung disease (ChILD) is an umbrella term encompassing a diverse group of diffuse lung diseases affecting infants and children. Although the timely and accurate diagnosis of ChILD is often challenging, it is optimally achieved through the multidisciplinary integration of imaging findings with clinical data, genetics, and potentially lung biopsy. This article reviews the definition and classification of ChILD; the role of imaging, pathology, and genetics in ChILD diagnosis; treatment options; and future goals. In addition, a practical approach to ChILD imaging based on the latest available research and the characteristic imaging appearance of ChILD entities are presented.

Principles and applications of dual source CT

This article describes the technical principles and clinical applications of dual source CT. A dual source CT (DSCT) is a CT system with two x-ray tubes and two detectors at an angle of approximately 90°. Both measurement systems acquire CT scan data simultaneously at the same anatomical level of the patient (same z-position). DSCT provides temporal resolution of approximately a quarter of the gantry rotation time for cardiac, cardio-thoracic and pediatric imaging. Successful imaging of the heart and the coronary arteries at high and variable heart rates has been demonstrated. DSCT systems can be operated at twice the spiral pitch of single source CT systems (up to pitch 3.2). The resulting high table speed is beneficial for pediatric applications and fast CT angiographic scans, e. g. of the aorta or the extremities. Operating both X-ray tubes at different tube potential (kV) enables the acquisition of dual energy data and the corresponding applications such as monoenergetic imaging and computation of material maps. Spectral separation can be improved by different filtration of the X-ray beams of both X-ray tubes. As a downside, DSCT systems have to cope with some challenges, among them the limited size of the second measurement system, and cross-scattered radiation.

Image Quality of Coronary Arteries on Non-electrocardiography-gated High-Pitch Dual-Source Computed Tomography in Children with Congenital Heart Disease

This study aimed to evaluate image quality of coronary artery imaging on non-electrocardiography (ECG)-gated high-pitch dual-source computed tomography (DSCT) in children with congenital heart disease (CHD) and to assess factors affecting image quality. We retrospectively reviewed the records of 142 children with CHD who underwent non-ECG-gated high-pitch DSCT. The subjective image quality of the proximal coronary segments was graded using a five-point scale. A score <3 represented a non-diagnostic image. Age, body weight, and heart rate were compared between the two groups: patients with good diagnostic image quality in all four segments and patients with at least one segment with non-diagnostic image quality. Predictors of image quality were assessed by multivariate logistic regression, including age, body weight, and heart rate. Four-hundred-fifty-seven of the 568 segments (80.5%) had diagnostic image quality. Patients with non-diagnostic segments were significantly younger (21.6 ± 25.5 months), had lower body weight (7.82 ± 5.00 kg), and a faster heart rate (123 ± 23.7 beats/min) (each p < 0.05) than patients with diagnostic image quality in all four segments (30.6 ± 20.7 months, 10.3 ± 4.00 kg, and 113 ± 21.6 beats/min, respectively; each p < 0.05). The multivariate logistic regression revealed that body weight (odds ratio 1.228; p = 0.029) was a significant predictor of image quality. Non-ECG-gated high-pitch DSCT provided adequate image quality of the proximal coronary segments in children with CHD. Lower body weight was a factor that led to poorer image quality of the coronary arteries.