320 Slice CT in Imaging of Congenital Heart Diseases in Infants: A Single-Center Experience

Abstract

Objective The study was conducted to evaluate the best possible imaging technique for neonatal cardiac imaging including optimal injection techniques, intravenous line placement, expected radiation dose, and need for sedation while performing the study on a 320 slice Toshiba® Aquilion ONE® scanner. Study results can be used to optimize imaging parameters for maximum clinical yield. We provide representative images of our cases. Methodology Cardiac CTs performed on infants less than one year of age at the time of study were evaluated. Data collection included radiation dose, duration of the scan, heart rate, type and route of contrast injection, need for sedation or general anesthesia and quality of study including image contrast and motion artifacts. Results Average age of infants at the time of scan was approximately two months. Prospectively gated volumetric scans performed within one heartbeat with a single gantry turn formed the majority of studies. Average effective dose was below 1 mSv. Several patients were scanned without any sedation. Most studies were deemed diagnostic and of superior quality on a 4-point scale. Qualitative image analysis revealed an excellent intraclass correlation between two raters. Conclusion Parameters needed for successfully performing cardiac CTs with a high degree of diagnostic quality in neonates were identified. For infants below a year hand injection of Isovue 300 in a 24 G peripheral upper extremity IV line with real-time contrast bolus monitoring and manual start to scanning is adequate when being scanned on a 320 slice Volumetric scanner with prospective auto-target EKG gating. Sedation may not be necessary for infants when wrap and feed techniques and free breathing are employed. Radiation doses utilizing this technique were uniformly low.

Keywords: infant cardiac imaging.

Figure 1. A and B: Axial and coronal images show streak artifacts (arrows) of moderate severity in the SVC in a patient with L-TGA (Congenitally corrected). C: 3D recons depict the great vessel origins. D: 3D recon depicts the B-T shunt.

Figure 2. A (3D) and B (coronal) images depict Type 2 truncus arteriosus (arrows). Injection was through the UVC in this one-day-old.

UVC: umbilical venous catheters.

Figure 3. Coronal (A and C) and 3D (B) images in a one-day-old with complex CHD – heterotaxy with midline liver (starred), total anomalous pulmonary venous return (TAPVR) (not shown), DORV with side-by-side origin of great vessels (straight arrow) and ASD (curved arrow) are all well depicted.

CHD: congenital heart disease; DORV: double outlet right ventricle.

Figure 4. A and B - sagittal images in a one-day-old with TOF (with absent pulmonary valve) show the aorta overriding the VSD (arrows) and C - axial images show dilated RPA (star) compressing the main stem bronchus, also seen on 3D recons (D and E).

TOF: Tetralogy of Fallot; VSD: ventricular septal defect; RPA: right pulmonary artery.