Application Of CARE KV And SAFIRE In Contrast-Enhanced CT Examination On Thorax

BackgroundImages acquired from computed tomography (CT) never look overexposed in the sense of being too light or dark, not like screen radiographs. The normalization of CT data to represent a fixed amount of attenuation relative to that of water ensures that the image always appears properly exposed. Thus, CT operators have not been noticed to decrease the tube current-time product or the peak kilo-voltage for scanning in the small size patients, and, so, such patients often were exposed to an excessive radiation dose. Now CT technology has entered the era of low dose. Following the minimum principle has become the consensus of the CT industry. That how to reduce the X ray dose as far as possible while maintain or improve the diagnostic image quality, is the current CT clinical research important content and direction. People have tried many ways to reduce the radiation dose, such as, current automatic adjustment technology, large pitch scanning technology of prospective ECG-controlled triggering in scanning step, Iterative reconstruction technique in Image reconstruction step. CARE kV and SAFIRE are the world’s latest low-dose technology in the CT scan and image reconstruction,currently. There have been related to clinical trials to prove that these two technologies can significantly reduce the dose of X-ray radiation, while maintain the good diagnostic image quality.ObjectiveTo evaluate the potential of automated tube potential selection algorithm (CARE kV) and Sinogram Affirmed Iterative Reconstruction (SAFIRE) on image quality improvement and radiation dose reduction of patients. Material and Methods60consecutive patients were enrolled and divided into2groups(group1; group2) with30patients per group.Group1underwent128-slice DSCT with routine scan, and images were reconstructed with FBP; group2underwent128-slice DSCT using an automated tube potential selection algorithm (CARE kV), images were reconstructed with FBP(group2a) and SAFIRE(group2b) separately.Two observers rated image quality using a5-point score (5:excellent to1:non-diagnostic) independently.Image attenuation and noise were measured, contrast-to-noise-ratio (CNR) was calculated, and the basic information of patients were recorded as well as operational radiation dose.ResultsAll the images were diagnostic(the average score of groups1,2a and2b is3.83,3.60,4.33,k=0.749,P=0.003). The image quality of group2b and2a is better than that of group1, and the CNR of group2a and2b was increased to16.7%(t=2.065,P=0.043),61.2%(t=6.312,P<0.001) compared with that of group1. The effective radiation dose of group2(2.26±0.77mSv) was significantly lower than that of group1(2.82±1.15mSv), corresponding to an overall dose reduction of19.7%(t=3.370,P=0.001)ConclusionThe combined application of both CARE kV and SAFIRE can improve image quality while reduce the radiation dose of patients. CARE kV alone, can not only reduce the radiation dose, but also can improve the contrast of the image under the premise of maintaining the same image CNR, but will cause image noise increasing. The combined application of both CARE kV and SAFIRE has the potential to reduce60%the radiation dose, while product similar quality images.