Objective To analyze various scanning parameters and contrast agent injection schemes,and explore the feasibility of three-low scanning technology characterized by lower radiation dose,slower injection rate and reduced contrast agent dosage in coronary angiography with wide-detector CT.Methods A total of 210 patients who underwent coronary angiography were recruited and randomly divided into group A(routine group,n=105)and group B(three-low group,n=105),and all of them were examined using the Revolution CT from the American GE company.Group A and group B adopted 120 and 100 kV tube voltages,respectively.The contrast injection rate and contrast agent dosage were calculated using formulas based on body mass index and beat per minute.Image quality was objectively evaluated using CT number,signal-to-noise ratio and contrast-to-noise ratio,and subjectively scored using Likert 5-point method.Results No statistical differences were found in the basic data between two groups(P>0.05).The CT numbers of the aortic sinus orifice in coronary artery images obtained from group A and group B were(442.70±58.26)and(454.11±62.36)HU,respectively.The differences between two groups in CT number,image score,signal-to-noise ratio,and contrast-to-noise ratio were trivial(P>0.05),while statistically significant differences were noted in injection rate,contrast agent dosage,tube current,and effective radiation dose(P<0.05).Group B reduced the effective radiation dose by 33.89%as compared with group A.Conclusion Based on the patient's body mass index and beat per minute,a personalized contrast agent injection scheme can be developed.Both routine group and three-low group can obtain image quality that meets imaging diagnosis requirements,and the latter has better image quality,demonstrating that the three-low scheme benefits the patients more for it can reduce the patient's radiation dose and contrast agent dosage while achieving higher image quality.

Objective To analyze various scanning parameters and contrast agent injection schemes,and explore the feasibility of three-low scanning technology characterized by lower radiation dose,slower injection rate and reduced contrast agent dosage in coronary angiography with wide-detector CT.Methods A total of 210 patients who underwent coronary angiography were recruited and randomly divided into group A(routine group,n=105)and group B(three-low group,n=105),and all of them were examined using the Revolution CT from the American GE company.Group A and group B adopted 120 and 100 kV tube voltages,respectively.The contrast injection rate and contrast agent dosage were calculated using formulas based on body mass index and beat per minute.Image quality was objectively evaluated using CT number,signal-to-noise ratio and contrast-to-noise ratio,and subjectively scored using Likert 5-point method.Results No statistical differences were found in the basic data between two groups(P>0.05).The CT numbers of the aortic sinus orifice in coronary artery images obtained from group A and group B were(442.70±58.26)and(454.11±62.36)HU,respectively.The differences between two groups in CT number,image score,signal-to-noise ratio,and contrast-to-noise ratio were trivial(P>0.05),while statistically significant differences were noted in injection rate,contrast agent dosage,tube current,and effective radiation dose(P<0.05).Group B reduced the effective radiation dose by 33.89%as compared with group A.Conclusion Based on the patient's body mass index and beat per minute,a personalized contrast agent injection scheme can be developed.Both routine group and three-low group can obtain image quality that meets imaging diagnosis requirements,and the latter has better image quality,demonstrating that the three-low scheme benefits the patients more for it can reduce the patient's radiation dose and contrast agent dosage while achieving higher image quality.

Objective:To investigate the association between bone lesions distribution and survival outcome and prognostic risk stratification in renal cell carcinoma bone metastasis (RCC-BM).Methods:The data of 122 RCC-BM patients admitted to Peking University People's Hospital between January 2009 and December 2019 were retrospectively reviewed. There were 100 males and 22 females, with a baseline age of (59.87±11.33) years old. According to the Memorial Sloan-Kettering Cancer Center (MSKCC)/Motzer score, patients were stratified into different risk groups using profiles at first bone metastasis diagnosis, with 20 (16.4%), 74 (60.6%) and 28 (23.0%) patients in favorable, intermediate and poor group, respectively. The spatial distribution of bone metastasis was investigated at the first bone metastasis diagnosis. The overall distribution patterns were as follows: locoregional group (lesions only involved thoracic and/or lumbar vertebrates) in 26 cases (21.3%), stochastic group (bone lesions randomly distributed) in 69 cases (56.6%), extensive group (with concomitant visceral metastasis) in 27 cases (22.1%). Metastatic site involvement was as follows: spine in 48 cases(39.3%), pelvis in 43 cases (35.2%), upper extremities in 22 cases (18.0%), and lower extremities in 20 cases (16.4%). Half (61 cases) of the enrolled patients had synchronous bone metastasis as their first bone metastases were diagnosed simultaneously with their renal tumors. Of all the patients, 99 (81.1%) accepted radical nephrectomy, 6 (4.9%) accepted partial nephrectomy, and the other 17 patients (13.9%) accepted the treatment of ablation or embolization. Eighty-two patients (67.2%) received definitive treatment for bone metastatic lesions, respectively. Forty patients (32.8%) accepted the palliative tumor reduction therapy. Thirty-two patients (26.2%) received tyrosine kinase inhibitor (TKI) or immune checkpoint inhibitor (ICI) medication, and 12 patients (9.8%) received local radiotherapy. Distribution variation and therapeutic strategies throughout the disease course until the last follow-up were recorded. Univariate analysis (chi-squared test, Mantel-Haenszel test), Kaplan-Meier survival analysis, and multivariate ordinal logistic regression were performed for the possible association.Results:Patients from the locoregional group (30.8%, 8/26) were prone to have higher risk stratification at first diagnosis than patients in the stochastic and extensive groups ( 20.8%, 20/96, P=0.107) as the marginal difference was found. At first bone metastasis diagnosis, RCC-BM patients with spinal involvement were more likely to have higher MSKCC risk stratification than those without spinal involvement [20.3%(15/48) vs. 17.6%(13/74), P<0.05]. Multivariate ordinal logistic regression showed that after adjusting for general data, bone metastasis sites, and concomitant visceral metastasis, RCC-BM patients with spinal involvement at first bone metastasis diagnosis were 3.3 times (95% CI 1.195-9.091, P<0.05)more likely to fall into the higher MSKCC risk group than those without spinal involvement.In those 93 cases with follow-up records, 20 (21.5%), 53 (57.0%), and 20 (21.5%) cases were in the locoregional group, stochastic group, and extensive group, respectively. The median overall survival time (mOS) of patients with pelvic involvement (36 cases) throughout the disease course was 32.0 months (95% CI 6.0-58.0), which was shorter than that of patients without pelvic involvement (57 cases, mOS 49.0 months, 95% CI 20.4-77.5, P<0.05). Conclusions:Spinal involvement (especially limited to thoracic and/or lumbar vertebrates) at first bone metastasis diagnosis and pelvic involvement throughout the disease course were associated with poor prognosis.

Objective: To investigate the smartphone addiction among college students during the Coronavirus Disease 2019 (COVID-19) pandemic and its association with daily behaviors and mental health,and to provide reference for heath education and psychological counseling for college students. Methods: An observational study using online quyestionnaire was conducted among 10 357 college students of two provincial medical schools in Guangdong and Shanxi Province from February 24th to March 4th in 2020. Participants were investigated on demographic information, smartphone addiction, daily routine, physical activity, weight status, anxiety, and other health information. Logistic regression with inverse probability treatment weighting (IPTW) based on propensity score was used to analyze the association between smartphone addiction with daily behavior and mental health. Results: The prevalence of smartphone addiction was 59.42%. The prevalence of phone addiction was higher in postgraduates, senior undergraduates, students with non-medical major, students living in GuangDong and those without regular exercise habit before vacation(χ 2=47.91，17.78，42.75，138.58，P<0.05). With IPTW, there were significant associations between smartphone addiction and late bedtimes (OR=1.82, 95%CI=1.66-1.98) and wake-up times (OR=1.55, 95%CI=1.44-1.68), more sedentary behaviors (OR=1.21, 95%CI=1.12-1.31), less moderate to vigorous physical activity (OR=1.33, 95%CI=1.22-1.44), anxiety (OR=2.98, 95%CI=2.52-3.40), weight gain(OR=1.27，95%CI=1.17-1.37) and other detrimental daily behavior and feelings. Conclusion High prevalence of smartphone addiction has been observed during the COVID-19 pandemic, with impaired daily behavior and mental health.

Since the outbreak of coronavirus disease 2019 (COVID-19), chest computed tomography (CT) has been an important imaging modality in the diagnosis, treatment and follow-up of patients with COVID-19,but meanwhile the risk of cross-infection between the staff and patients in Department of Radiology is increasing. Shelter CT is specifically used for the examination of patients with suspected or confirmed COVID-19 to reduce the infection risk. Based on practical work experience, the management and prevention measures for COVID-19 in shelter CT are discussed from the aspects of the installation, function division and examination procedures of shelter CT, patient examination route, the staff management and infection prevention for radiology technologists, and the disinfection of CT equipments and object surface.