Application Of CARE KV And SAFIRE In Contrast-Enhanced CT Examination In Chest Lesions

BackgroundCT scan is an important method for the diagnosis of chest diseases, and the sensitivity and specificity are relatively high, but X-ray is a double-edged sword, it can make patients exposed to radiation while satisfying the diagnosis of the disease. In the medical work of CT examination,there is a hazard that the radiation dose is too high.CT is an important source of iatrogenic radiation,and now the development of CT technology has entered the era of low dose imaging. We follow the the principle of ALARA (as low as reasonably achievable),and use the radiation reasonably,and this has become the consensus.As the self protective consciousness is more and more urgently,so how to get the good image that can satisfy the diagnosis of the disease while reducing the radiation dose during CT scanning has become an important problem for radiological workers.In order to reduce the radiation of CT scanning,we have made many attempts, such as lowering the tube voltage and tube current,and with high-pitch during the scanning,using using iterative reconstruction techniques during the image reconstruction process.There have been two new technologies: CARE kV and SAFIRE, and they play the role in the scanning and image reconstruction process respectively. Many clinical practices have proved that these two kinds of techniques can guarantee the good image while reducing the radiation dose,or improve the quality of the image significantly while use the conventional scanning.ObjectiveTo evaluate the potential of combined use of automated tube potential selection algorithm (CARE kV) and Sinogram Affirmed Iterative Reconstruction (SAFIRE) can not only meet the requirements of the diagnosis of the disease while improving image quality,but also can reduce the radiation dose of patients.Methods90patients with lung mass using Siemens SOMATOM Flash CT were enrolled and divided into3groups (group1; group2; group3) with30patients per group. Group1underwent128-slice DSCT with routine scan, and images were reconstructed with filtered back projection (FBP); Group2and3underwent128-slice DSCT using an automated tube potential selection algorithm (CARE kV) with tube current of90mAs(group2) and80mAs(group3), images were reconstructed with SAFIRE. Two blinded, independent readers measured image quality on a five-point scale (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 interobserver agreement for image quality rating was good (k=0.749, P=0.003). The image quality of group2、3are better than that of group1, and the CNR of group2、3are increased by19.3%(t=6.312, P<0.001)、14.7%,(t=-1.730, P=0.088) compared with that of group1; The effective radiation dose of group2(2.06±0.47mSv)、3(1.88±0.51mSv) are significantly lower than that of group1(2.86±0.56mSv), corresponding to an overall dose reduction of27.9%(t=6.461, P<0.001)、34.2%,(t=7.556, P<0.001). The image quality of group3is better than that of group2, and the CNR of group2was increased by4.0%,(t=0.592, P=0.555) compared with that of group2. The effective radiation dose of group3(1.88±0.51mSv) was significantly lower than that of group2(2.06±0.47mSv), corresponding to an overall dose reduction of8.7%,(t=1.634, P=0.106).ConclusionThe combined application of both CARE kV and SAFIRE can improve image quality while reduce the radiation dose of patients.