Evaluation of Contrast Injection Site Effectiveness: Thoracic CT Angiography in Children With Hand Injection of IV Contrast Material

OBJECTIVE. The purpose of this study was to evaluate the effectiveness of various contrast injection sites when performing thoracic CT angiography (CTA) using hand injection of IV contrast material in infants and young children with a small IV catheter. MATERIALS AND METHODS. We used our hospital information system to retrospectively identify consecutive pediatric patients who underwent thoracic CTA with hand injection of contrast material from August 2012 to July 2013. The study indication for thoracic CTA was to evaluate the thoracic systemic arterial vasculature and pulmonary venous vasculature. Both qualitative and quantitative evaluation of thoracic CTA image quality was performed by two reviewers independently. Qualitative evaluation of thoracic CTA image quality was performed by visual assessment of the degree of contrast enhancement in the ROI on a 4-point scale. Quantitative evaluation was performed by measuring attenuation obtained with the ROI placed within the aorta at two locations (the level of the aortic arch and at the level of the carina) to evaluate the thoracic systemic arterial vasculature. For evaluation of the pulmonary venous system, attenuation measurements were obtained at the center of the left atrium. Six individual injection sites were identified: head, jugular vein, arm vein, hand vein, leg vein, and foot vein. Injection sites were categorized into three regional groups: head-neck region (head vein and jugular veins), upper extremity region (arm and hand veins), and lower extremity region (leg and foot veins). Comparisons of attenuation values between individual and regionally grouped contrast injection sites were determined using the F-test in ANOVA. RESULTS. The study cohort included 50 pediatric patients (29 boys and 21 girls; mean age, 8 months ± 1 year; range, 1 week to 5 years) who underwent a total of 50 thoracic CTA studies for evaluating the thoracic systemic arterial vasculature (n = 38; 76%) or pulmonary venous vasculature (n = 12; 34%). All 50 thoracic CTA studies were of diagnostic quality on the basis of qualitative evaluation (all ≥ 3). For quantitative evaluation with the threshold for a diagnostic thoracic CTA study defined as attenuation greater than 150 HU in the ROI, all 50 thoracic CTA studies were technically successful (aortic arch, 380 ± 150 HU; descending thoracic aorta at the level of the carina, 392 ± 155 HU; and left atrium, 352 ± 90 HU). There were no significant differences in mean attenuation between individual injection sites (p > 0.20 for each comparison) or different regional groups (p > 0.50 for each comparison). CONCLUSION. Diagnostic quality thoracic CTA can be achieved with hand injection of IV contrast material in infants and young children with a small IV catheter, independent of the IV access site.