Torel Ogur MD, Abstract Co-Author: Nothing to Disclose

Patrick T. Norton MD, Presenter: Nothing to Disclose

Juan Carlos Ramirez Giraldo PhD, Abstract Co-Author: Employee, Siemens AG

Klaus D. Hagspiel MD, Abstract Co-Author: Research Grant, Siemens AG

To compare the radiation dose and image quality of pediatric cardiac computed tomography angiography (CCTA) examinations using existing scan modes on dual source (DS) scanners.

CCTA scans of 56 pediatric patients (age range 1d - 18yrs, mean 7.8±7.9 yrs) were reviewed retrospectively. Scans were performed on first or second generation DS CT systems. Scans were divided into 3 groups according to scan mode: retrospective ECG-gated helical (RETRO) (n=33), prospective ECG-triggered sequential (PRO) (n=8) and high-pitch spiral (FLASH) (n=15). The impact in radiation dose of automated dose-optimized selection of x-ray tube voltage (CARE kV), available in second generation DS scanner, was also assessed, relative to manual tube voltage selection in first generation DS. Size-specific dose estimate (SSDE) and effective dose were calculated. Image quality was assessed qualitatively by two radiologists on a 5 point Likert scale.

For RETRO scans, PRO scans and FLASH scans the mean effective dose values (mSv) were 3.90±2.98, 3.33±2.13, and 2.01±1.05 and mean SSDE values (mGy) were 13.90±9.52, 13.85±12.14, and 4.23±2.69. The differences in effective doses between RETRO and FLASH modes were statistically significant (p<0.04). For SSDE, differences between RETRO and FLASH and PRO and FLASH were significant (p<0.02). CARE kV was applied in 19 patients resulting in mean effective dose and SSDE of 2.10±1.04 mSV, 5.83±4.63 mGy versus 3.89±2.91 mSv and 13.90±10.29 mGy for the remaining 37 patients. For the effective dose and SSDE, the difference between scans with or without CARE kV was statistically significant (p<0.02). Average image quality scores were 4.45, 4.50 and 4.47 for RETRO, PRO, and FLASH, respectively; and 4.47 for scans with CARE kV and 4.46 for scans without. Pearson Χ2 revealed no difference in image quality based on the presence of CARE kV or based on the scan mode used.

Using high pitch spiral mode, low RD pediatric DS CCTA can be performed without sacrificing quality. The use of automated dose-optimized selection of kV resulted in the lowest doses.

When using DS scanners for pediatric cardiac CTA, high pitch spiral mode and automatic kV selection should be employed to produce high quality examinations with the minimal radiation dose possible.

Ogur, T, Norton, P, Ramirez Giraldo, J, Hagspiel, K, Dual Source Pediatric Cardiac Computed Tomography—Techniques and Radiation Dose.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13027935.html