Patient history

7 day-old girl with transposition of the great arteries (TGA) and ventricular septum defect. Ultrasound is inconclusive especially regarding the pulmonary arteries, veins and possible aorto pulmonary collateral arteries.

Technique

The CT exam of the Thoracic Aorta and Heart was performed on the Discovery CT750 HD.
Parameter settings: 80 kVp @ Pitch 0.969:1, with the use of Auto mA/Smart mA (NI 28), leading to 30-40 mAs. ASiR image reconstruction was used. Total scan time was 2.8 seconds for a coverage of 108 mm.
DLP of the exam is 27.6 mGy.cm, including Smart Prep, resulting to be 1.08 mSv*.

Obtained using ICRP 0-year-old Chest factor of 0.039 * DLP. Reference: Annals of the ICRP, Volume 37, Issue 1, March 2007.

Findings

A significant stenosis of the proximal part of the right pulmonary artery was discovered, together with a stenosis and anomaly of the right main bronchus. One significant aorto pulmonary collateral artery originated from the abdominal aorta at the level of the coeliac trunk. This collateral supports the lower lobe of the right lung. No other collaterals were depicted. The pulmonary veins are located properly. Confirmation of the ventricular septal defect together with an open arterial duct.

Conclusion

“This exam highlights one of the reasons why we bought a new CT.
The Discovery CT750 HD has allowed us to minimize significantly radiation dose on this small patient who presented a transposition of the great arteries. We scan about 80-90 patients with congenital heart failure per year on CT. When Ultrasound is not conclusive CTA gives us excellent morphological information.”

F. Stålhammar, M.D.

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