AJR:190, February 2008
Dagmar Honnef, Joachim E. Wildberger, Gabriel Haras, Christian Hohl, Gundula Staatz, Rolf W. Gunther, Andreas H. Mahnken
Objective: The purposes of this study were to evaluate prospective adjustment of dose settings in pediatric 16-MDCT by use of computer-simulated images in a patient image gallery and to compare the dose reduction achieved with that of standard pediatric protocols.
Subjects and Methods: The image gallery consisted of images from weight-dependent sample examinations performed with varied simulated tube current-exposure time settings. The scanning parameters prospectively chosen on the basis of the image quality of the image gallery were used for 30 16-MDCT examinations (chest, n = 15; abdomen, n = 8; pelvis, n = 7) of 22 children (14 boys, eight girls; mean age, 6.8 ± 5.8 years; mean body weight, 26.7 ± 19.6 kg). Three blinded radiologists used a 4-point grading scale to rate the overall image quality of the image gallery and the 16-MDCT scans. Objective and subjective image quality was assessed for the simulated and actual CT scans. The concordance correlation coefficient (K) was determined.
Results: There was mainly moderate concordance with regard to objective (chest, K = 0.69; abdomen, K = 0.33; pelvis, K = 0.55) and subjective (chest soft-tissue window, kappa coefficient [K] = 0.00; chest lung window, K = 0.53; abdomen, K = 1.00; pelvis, K = 0.48) analysis of image gallery compared with actual 16-MDCT examinations. Compared with use of previous weight-adapted pediatric standard protocols, use of an image gallery resulted in further dose reduction for abdominal and pelvic CT but not for thoracic CT.
Conclusion: A patient image gallery can be used as a basis for pediatric 16-MDCT examinations. The gallery provides a preexamination overview of expected image quality. Radiation exposure can be optimized with regard to patient weight and the image quality needed to answer the clinical question.