Chest CTA in children younger than two years - a retrospective comparison of three contrast injection protocols

Pediatric Applications of Photon-Counting Detector CT

Photon-counting detector (PCD) CT represents the most recent generational advance in CT technology. PCD CT has the potential to reduce image noise, improve spatial resolution and contrast resolution, and provide multispectral capability, all of which may be achieved with an overall decrease in the radiation dose. These effects may be used to reduce the iodinated contrast media dose and potentially obtain multiphase images through a single-acquisition technique. The benefits of PCD CT have previously been shown primarily in phantoms and adult patients. This article describes the application of PCD CT in children, as illustrated by clinical examples from a commercially available PCD CT system.

Cardiothoracic CTA in Infants Referred for Aortic Arch Evaluation-Retrospective Comparison of Iomeprol 350, Ioversol 350, Iopromide 370 and Iodixanol 320

Background: Computed tomography angiography (CTA) in infants is considered one of the most challenging radiological examinations due to difficulties in balancing start delay, contrast agent (CA) volume and flow in order to achieve optimal opacification of the large vessels. This study aimed to compare the contrast enhancement achieved by four CAs when taking into consideration CA injection parameters and patient characteristics. Methods: We performed a retrospective assessment of forty-eight consecutive cardiothoracic CTAs performed for aortic arch evaluation on children aged 0–1 year. All examinations were performed using the same 64-slice scanner and power injector using the bolus tracking technique. Axial 0.6 mm slices were used to measure large vessel enhancement using regions of interest at the level of the main pulmonary artery, ascending and descending aorta. The recorded variables included anthropometric measurements, CA type, flow rate, volume, and the average Hounsfield unit (HU) values of the blood pool. Descriptive statistics are presented as averages and standard deviations (SD) for normal distributed data or otherwise as medians and interquartile ranges (IQRs). Results: We found no statistically significant differences between age and anthropometric parameters when looking at different CAs. The median CA volume was 7 (IQR, 7–9) mL with the average flow rate of 0.94 (SD, 0.23) mL/s. Ascending aorta average HU values were 605.9 (SD, 177.23) for Iomeprol 350, 626 (SD, 183.83) for Ioversol 350, 530.83 (SD, 175.56) for Iopromide 370 and 354.91 (SD, 115.81) for Iodixanol 320. The difference in HU value for Iodixanol 320 compared to the other CAs was statistically significant. Similar differences were found for the other vascular structures. Conclusion: In CTA of infants suspected of aortic arch hypoplasia/coarctation, Iodixanol 320 provided up to 40% less enhancement of the great vessels when compared to Iomeprol 350, Ioversol 350 and Iopromide 370.