Optimal Multidetector Row CT Parameters for Evaluations of the Breast: A Phantom and Specimen Study

Abstract

The use of breast computed tomography (CT) has been limited by radiation hazard and image quality. The objective of this study was to compare radiation doses and image quality for different 64-channel multidetector row CT (MDCT) parameters, and to potentially provide optimal CT parameters for breast imaging. For assessment of radiation doses, CT dose index (CTDI(100)) values were obtained at various x-ray tube voltages (80, 120, 140 kVp) and currents (30, 50, 100, 150, 200 mAs) using a standard CT body dose phantom. To evaluate image quality, four fresh mastectomy specimens were scanned and three radiologists graded images for overall image quality, glandular tissue-fat conspicuity, and Cooper's ligament sharpness. Statistically, linear regression analyses and multiple comparisons were used for investigation of the relationship between radiation dose, image qualities, and CT parameters. CTDI(100) values of < or =6 mGy were obtained at 80 kVp and any mAs, 120 kVp and 30 or 50 mAs, and 140 kVp and 30 or 50 mAs. Image quality at 80 kVp and 200 mAs, 120 kV and 50, 100, 150, or 200 mAs, and 140 kVp and all mAs values tested were significantly superior to those at 80 kVp and 30, 50, 100, or 150 mAs and 120 kV and 30 mAs (P < .05). Based on our results, 80 kVp and 200 mAs, 120 kVp and 50 mAs, 140 kVp and 30 mAs, or 140 kVp and 50 mAs can be used for breast MDCT scanning to reduce radiation dose and preserve image quality and 140 kVp at 30 mAs is the optimal setting.