Low-dose MSCT pulmonary angiography: low kVp with individual-adapted low tube current

Objective: To assess the feasibility of low-dose MDCT pulmonary angiography (MDCTPA) by using low kVp combined with individual-adapted low tube current protocol and noise reduction filter algorithms. Methods: Fifty-six consecutively patients with MDCTPA were enrolled in the study. The patients were randomly divided into group A (120 kVp, 100 mAs) and group B (100 kVp, individual-adapted tube current about 1.0 mAs/kg). Two series of images were reconstructed in group B: B1 with standard filter algorithms (FC13, B1) and B2 with noise reduction filter algorithms (FC11, B2). The image noise, quality and radiation dose in two groups were compared. Results: The CTDI_vol, DLP and E of group B were 5.1 mGy, 83.3 mGy·cm and 1.4 mSv respectively, which were reduced by 64.3%, 66.4% and 66.7%, respectively(F =32.57, 12.32, 11.98, P < 0.05) when compared with those in group A. Compared with group A, the image noise in B1 was increased by 118.2%(t = 10.05 P < 0.05), the central and peripheral SNR and CNR and scores were increased by 51.5%, 46.6%, 50.8%, 45.3% and 20.4%, respectively(t = 7.20, 6.30, 6.58, 5.54, 8.35, P < 0.05). Compared with B1, the image noise in B2 was reduced by 32.5%(t = 6.12, P < 0.05), the central and peripheral SNR and CNR and scores were increased by 46.2%, 46.2%, 45.9%, 46.9% and 18.4%(t = 3.19, 3.55, 2.95, 3.37, 5.42, P < 0.05). Compared with group A, the image noise in B2 group was increased by 47.3%(t = 4.03, P < 0.05), the central and peripheral SNR and CNR and scores were reduced by 29.1%, 21.8%, 28.2%, 19.6% and 8.2%(t = 4.06, 2.82, 3.68, 2.22, 3.02, P < 0.05). Conclusions: Keeping effective diagnostic image quality, the protocol with low kVp and individual-adapted low tube current for low-dose MDCT pulmonary angiography would be effective and feasible, and the radiation dose would be significantly reduced. (authors)