Objective: This study is to investigate the possibility of CT Pulmonary Angiography (CTPA) at low kV and low-concentration contrast medium using iterative reconstruction technique.
Methods: Ninety suspected cases of Pulmonary Embolism (PE) scheduled for CTPA were randomly and equally divided into 3 groups (group A, B and C). The dose of the contrast medium was 270 mg/ml, 350 mg/ml and 370 mg/ml, respectively. CT values of the pulmonary trunk together with the left and right pulmonary artery were measured. The image quality was assessed based on Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR). Gender distribution and scores of image quality were compared using Kappa statistics.
Results: The three groups showed no significant difference in gender, age, height, body weight and BMI. The subjective and objective image quality of CTPA did not differ significantly among the three groups. Subjective evaluation showed a high consistence (p=0.85) and the images were all sufficient for diagnosis. The effective dose of group A was considerably lower than that of group B and C.
Conclusion: By using iterative reconstruction, CTPA images acquired at low kV and low-concentration contrast medium were of comparable quality as conventional CTPA images.