Objective To evaluate the feasibility of low-tube-voltage, low injection rate, low contrast agent dosage in combination with iterative model reconstruction ( IMR) algorithm in CT angiography ( CTA) of the head-and-neck vessels .Methods Sixty patients who underwent CT angiography of the head-and-neck vessels were randomly divided into groups A and B with 30 cases in each group .Patients in group A received a conventional scan with 120 kVp and filterback projected ( FBP) reconstruction .Patients in group B received a low-dose scan with 80 kVp, and image reconstruction with FBP ( group B1) and IMR (group B2)algorithm.The contrast agent protocol were as follows: the injection time in all patients was 10s, the injection rate was 4.5-5.5 ml/s in group A while 3.5-4.0 ml/s in group B.The CT values of artery, image noise, signal to noise ratio ( SNR) and contrast to noise ratio ( CNR) were measured and compared among three groups with One-way ANOVA analysis . Image quality was evaluated by two radiologists with five scale method , and compared with Kruskal-Wallis test .The CT dose index volume (CTDIvol) and dose length product ( DLP) were recorded and compared between groups with two independent samples t-test.Results The image quality scores of groups A , B1and B2 were 3-5, 2-4 and 3 -5, respectively .Image quality of twelve patients in group B 1 couldn′t meet the diagnostic requirements but none in group A and B 2.The objective image parameters SNR and CNR for group B 2 were equal to group A ( P >0.05), while those for group B1 were lower than group A (t=13.39, 9.45, P<0.05) and group B2 (t=-12.14, -9.96,P<0.05).CTDIvol and DLP for group B were separately 80.9%, 81.3%lower than those of group A(t=39.1, 32.2,P<0.05).The injection rate and contrast agent volume for group B were separately 22.0%, 22.1% lower than those of group A ( t=20.8, 20.8, P<0.01) .Conclusions It is feasible in CT angiography of the head-and-neck vessels with lower tube-voltage, lower injection rate, lower contrast agent dose and combining with iterative model reconstruction algorithm.This protocol can reduce the radiation dose by 81.3% while maintaining image quality .Trial registration Chinese clinical trial registry ,ChiCTR-BOC-16010060.

The development of gastritis is associated with an increased risk of gastric cancer. Current invasive gastritis diagnostic methods are not suitable for monitoring progress. In this work based on 78 gastritis patients and 50 healthy individuals, we observed that the variation of tongue-coating microbiota was associated with the occurrence and development of gastritis. Twenty-one microbial species were identified for differentiating tongue-coating microbiomes of gastritis and healthy individuals. Pathways such as microbial metabolism in diverse environments, biosynthesis of antibiotics and bacterial chemotaxis were up-regulated in gastritis patients. The abundance of Campylobacter concisus was found associated with the gastric precancerous cascade. Furthermore, Campylobacter concisus could be detected in tongue coating and gastric fluid in a validation cohort containing 38 gastritis patients. These observations provided biological evidence of tongue diagnosis in traditional Chinese medicine, and indicated that tongue-coating microbiome could be a potential non-invasive biomarker, which might be suitable for long-term monitoring of gastritis.