The investigation on image quality and radiation dose of low dose wider detector array CT scanning for young children with congenital heart disease

Objective: To investigate the image quality and radiation dose of the wider detector array CT scanner with low dose scanning mode in young children with congenital heart disease. Methods: Totally 100 consecutive pediatric patients younger than 3 years with congenital heart disease were enrolled. They were divided into two groups. The low dose group with fifty patients underwent axial CT scanning with ECG gating, and the control group with fifty patients were scanned with volume helical shuttle (VHS) technique. CT number and noise of two groups images at the level of ascending aorta, main pulmonary artery, left ventricle, descending aorta and adjacent muscle were measured, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The double blind method was used to evaluate subjective image quality of the level of intra-cardiac, extra-cardiac and coronary artery. Effective dose was also calculated for both groups. Results: No significant difference was found in the CT number, image noise, SNR, and CNR between the two groups in the same anatomic regions (P > 0.05). No significant difference was found in subjective image quality between the two groups for the intra-cardiac and extra-cardiac structure (P > 0.05). The subjective image quality of coronary artery was significant higher in low dose group than the control group (4.10 ± 0.90 vs. 2.88 ± 0.82, Z = -5.818, P < 0.05). Effective dose was (0.57 ± 0.30) mSv in group A and (2.39 ± 1.15) mSv in group B with dose savings of 76% (t = -11.642, P < 0.05). Conclusions: The wider detector array CT scanner with low dose scanning mode can improve image quality with lower radiation dose. (authors)