Computed Tomography Angiography with Three-dimensional Reconstruction for Pulmony Venous Definition in High-risk Infants with Congenital Heart Disease

Positional Relationship Between the Pulmonary Venous Confluence-Vertical Vein and Atria in Infracardiac Total Anomalous Pulmonary Venous Connection

To explore the positional relationship between the pulmonary venous confluence-venous vein (PVC-VV) and both the atria in infracardiac total anomalous pulmonary venous connection (iTAPVC), using two-dimensional (2D) computerized tomography (CT) reconstruction. Through the 2D reconstruction of enhanced cardiac CT images of patients with iTAPVC, the projection of PVC-VV on coronal axial images was acquired and its location on the bilateral atrial splice was analyzed. Sagittal axial reconstruction was used to identify which atrium had a precise anterior-posterior positional relationship with PVC-VV. The type of iTAPVC, where the projection of PVC-VV was lying on the left atrium, and the left atrium had a precise anterior-posterior positional relationship with PVC-VV, was classified as the left atrial type. If the projection of PVC-VV was lying on the right atrium and the right atrium had a precise anterior-posterior positional relationship with PVC-VV, it was classified as the right atrial type. Finally, if the projection of PVC-VV was lying in the middle of the bilateral atria, and both the atria had precise anterior-posterior positional relationship with PVC-VV, it was referred to as the bilateral atrial type. Upon analysis of the 22 enhanced cardiac CT images, 6 were the left atrial type (27.27 %), 9 were right atrial type (40.91 %), while 7 were of the bilateral atrial type (31.82 %). The positional relationship between PVC-VV and the bilateral atria are variable, and iTAPVC classification using 2D CT reconstruction is an invaluable tool in designing the surgical approaches in iTAPVC.

Radiation dose reduction in pediatric cardiac computed tomography: experience from a tertiary medical center

Cardiac CT angiography (cCTA) has become an established method for the assessment of congenital heart disease. However, the potential harmful effects of ionizing radiation must be considered, particularly in younger, more radiosensitive patients. In this study, we sought to assess the temporal change in radiation doses from pediatric cCTA during an 8-year period at a tertiary medical center. This retrospective study included all patients ≤18 years old who were referred to electrocardiography (ECG)-gated cCTA for the assessment of congenital heart disease or inflammatory disease (Kawasaki disease) from November 2004 to September 2012. During the study period, 95 patients were scanned using 3 different scanner models-64-slice multidetector CT (64-MDCT) and first- (64-DSCT) and second-generation (128-DSCT) dual-source CT-and 3 scan protocols-retrospective ECG-gated helical scanning (RG), prospective ECG-triggered axial scanning (PT), or prospective ECG-triggered high-pitch helical scanning (HPH). Effective dose (ED) was calculated with the dose length product method with a conversion factor (k) adjusted for age. ED was then compared among scan protocols. Image quality was extracted from clinical cCTA reports when available. Overall, 94 % of scans were diagnostic (80 % for 64-slice MDCT, 93 % for 64-slice DSCT, and 97 % for 128-slice DSCT).With 128-DSCT, median ED (1.0 [range 0.6-2.0] mSv) decreased by 85.8 % and 66.8 % compared with 64-MDCT (6.8 [range 2.9-13.6] mSv) and 64-DSCT (2.9 [range 0.9-4.1] mSv), respectively. With HPH, median ED (0.9 [range 0.6-1.8] mSv) decreased by 59.4 % and 85.4 % compared with PT (2.2 [range 0.9-3.4] mSv) and RG (6.1 [range 2.5-10.6] mSv). cCTA can now be obtained at very low radiation doses in pediatric patients using the latest dual-source CT technology in combination with prospective ECG-triggered HPH acquisition.

Effective radiation dose in computed tomographic angiography of the chest and diagnostic cardiac catheterization in pediatric patients

Computed tomographic angiography (CTA) and cardiac catheterization are useful adjuncts to echocardiography for delineating cardiovascular anatomy in pediatric patients. These studies require ionizing radiation, and it is paramount to understand the amount of radiation pediatric patients receive when these tests are performed. Modern dosimetry methods facilitate the conversion of radiation doses of varying units into an effective radiation dose. To compare the effective radiation dose between nongated CTA of the chest and diagnostic cardiac catheterization in pediatric patients. This is a retrospective cohort study of patients of patients who underwent either nongated CTA of the chest or diagnostic cardiac catheterization between July 2009 and April 2010. Fifty patients were included in each group as consecutive samples at a single tertiary care center. An effective radiation dose (mSv) was formulated using conversion factors for each group. The median effective dose (ED) for the CTA group was 0.74 mSv compared with 10.8 mSv for the catheterization group (p < 0.0001). The median ED for children <1 year of age in the CTA group was 0.76 mSv compared with 13.4 mSv for the catheterization group (p < 0.0001). Nongated CTA of the chest exposes children to 15 times less radiation than diagnostic cardiac catheterization. Unless hemodynamic data are necessary, CTA of the chest should be considered in lieu of diagnostic cardiac catheterization in patients with known or presumed cardiac disease who need additional imaging beyond echocardiography.