Evaluation of ventricular septal defects using high pitch computed tomography angiography of the chest in children with complex congenital heart defects below one year of age

Abstract

Background: Aim of this study was to assess the accuracy of ventricular septal defects (VSD) using high pitch computed tomography angiography (CTA) of the chest in children below 1 year of age, compared to the intraoperative findings and echocardiography.

Methods: Out of 154 patients that underwent Dual-Source CTA of the chest using a high-pitch protocol at low tube voltages (70-80 kV), 55 underwent surgical repair of a VSD (median age 8 days, range 1-348 days). The margins of the VSDs and their relation to the surrounding structures were reproduced by en-face views using multiplanar reformations (MPR). Absolute diameter, normalized area and relative area compared to the aortic valve annulus were used for discrimination between restrictive and non-restrictive defects. Localization was classified into four subtypes. The results were compared to two-dimensional echocardiography and intraoperative findings.

Results: Median absolute size of VSDs did not differ significantly between CTA-measurements (10.8 mm, range 2.8-18.1 mm) and intraoperative findings (12.0 mm, 3.0-25.0 mm, p = 0.09). Echocardiographic values were significantly lower (9.6 mm, 3.0-18.5 mm, both p < 0.01). The classification of the location and orientation matched the intraoperative situs in 96.4% of all cases using CT and in 87.3% using echocardiography. Echocardiography missed the relation to valves in 11% of all cases. Pre-interventional sensitivity and specificity for detection of a VSD were 97.2/98.9% compared to echocardiography. Median radiation dose was 0.32 mSv (range 0.12-2.00 mSv) and differed significantly between second and third generation Dual-Source CT (0.43 vs. 0.22 mSv, p = 0.003).

Conclusion: Size and subtype of VSDs can be accurately assessed by CTA of the chest in patients with complex congenital heart defects at a very low radiation dose.

Keywords: Computed tomography angiography; Congenital heart defect; Dual-source; High pitch; Ventricular septal defect.