Objective To assess the effectiveness of Z-axis automatic tube current modulation ( ATCM) technique with respect to dose reduction and image noise in the thyroid regional tissues during neck computed tomography angiography (CTA). Methods A total of 140 patients underwent neck CTA with 64-slice spiral CT, and were randomized into fixed-tube current group and ATCM group. Objective noise, CTDIw, DLP and mA of each group were recorded. Results The image qualities of all the patients were diagnostically acceptable, though the objective noise of neck in the ATCM group was higher than that in the group of fixed-tube current (P＜ 0.05 ). The radiation doses in the ATCM group [ CTDIw (35.99±1.31 ) mGy, DLP (11 121.39 ±5.51) mGy·cm] were significantly inferior to those in the group of fixed tube current [ CTDIw (43.22±1.42) mGy, DLP (1514.45±5.56) mGy·cm]. Conclusions Compared with fixedtube current technique, ATCM technique could significantly reduce the radiation dose in neck CT with diagnostic acceptability of the image quality.

Objective:To summarize the clinical and high resolution CT(HRCT) characteristics of 141 patients with COVID-19.Methods:From January 20 to 28, 2020, 141 COVID-19 patients, 77 males and 64 females, with a median age of 49 (9, 87), were enrolled in the study. The clinical features, laboratory test results and HRCT findings of all patients were analyzed retrospectively.Results:In all of the patients, the decreasing leukocyte countin 38 (26.95%) and lymphocyte ratio in 71 (50.35%), a fever over 37.5 ℃ in 139 (98.58%), coughing in 106 (75.18%), headache in 11 (7.80%), expectoration in 41 (29.08%), chest distress in 93 (65.96%), and diarrhea in 4 (2.84%) were found. The HRCT of all patients were abnormal, including ground glass opacity (GGO) with patchy opacity in 52 (36.88%) mainly distributed along subpleural area, GGO with focal consolidation in 23 (16.31%),small patchy opacity in 27 (19.15%),large patchy consolidation in 20 (14.18%),thickened bronchovascular bundleing and blood vessel crossing the lesion in 48 (34.04%), air bronchus sign in 5 (3.55%), small nodule in 7 (4.96%),fibrous stripes and reticular opacities in 5 (3.55%), bilateral pleural effusion in 7 (4.96%), and mediastinal or bilateral hilar lymphadenopathy in 4 (2.84%).Conclusions:The clinical and HRCT manifestations of COVID-19 are various. Under the specific epidemiological background of COVID-19, chest HRCT scan should be carried out as soon as possible for early warning of this disease.

Objective:To explore the value of low-dose CT in pregnancy with COVID-19.Methods:A retrospective analysis was performed on the clinical characteristics, laboratory tests, and chest CT findings of 12 pregnant women with COVID-19 diagnosed by nucleic acid testing in the Renmin Hospital of Wuhan University from January 20, 2020 to February 16, 2020. Two radiologists blinded to the reconstruction algorithm independently scored subjective image quality on a 5-point Likert scale. Image quality score ≥ 3 was acceptable in clinics. The CT radiation doses were recorded, including CT volume dose index (CTDI vol), dose length product (DLP), and effective radiation dose ( E). Two radiologists observed the distribution, shape, density, and other characteristics of lung lesions, and they also decided whether hilar, mediastinal lymphadenopathy, and pleural changed. Results:A total of 12 pregnant women with COVID-19, 8 had cough, 4 had fever, 2 had chest tightness, and 1 had dyspnea and diarrhea each. The CT image quality score of all patients was 3-4, with an average of 3.46, which fully met the clinical diagnosis requirements. The CTDI vol value was 1.13-4.31 mGy, with an average of 3.02 mGy. The DLP value was 34.48-75.29 mGy·cm, with an average of 55.48 mGy·cm. The Evalue was 0.48-1.05 mSv, with an average of 0.78 mSv. In all cases, chest CT examination showed abnormal manifestations after clinical symptoms, including unilateral lung lesions in 5 cases and bilateral lung lesions in 7 cases, 1 case of ground-glass opacity, 1 case of solidification, 7 cases of ground-glass and consolidation, 1 case of strip opacity, ground-glass, and consolidation and strip cable shadow coexisted in 2 cases. Conclusions:The application of low-dose CT scan in pregnant women with COVID-19 is completely feasible. CT mainly manifested as bilateral lung patchy and flaky ground-glass opacity with consolidation. Active and effective treatment can help recover and improve prognosis.

Objective:To explore the value of chest low-dose CT (LDCT) in post-discharge follow-up assessments of patients with coronavirus disease 2019 (COVID-19).Methods:The chest CT findings of 58 patients with COVID-19 from March 17 to March 25, 2020 at Remin Hospital of Wuhan University were retrospectively analyzed. Two radiologists independently scored the subjective image quality on a 5-point Likert scale. The signal-to-noise ratio (SNR) and SD air of images and the CT radiation dose parameters were calculated, including the CT volume dose index (CTDI vol), dose length product (DLP), and effective radiation dose ( E). Results:The subjective image quality scores on CT images obtained before and after discharge by readers 1 and 2, were 4.45±0.22, 3.88±0.33 ( P>0.05) and 4.37±0.18, 3.91±0.35 ( P>0.05), respectively. The SNR and SD air in LDCT after discharge were 4.39±0.95 and 7.19±2.41, which were significantly lower than those in routine chest CT before discharge (5.14±1.06, Z=-5.551, P<0.001; 6.48±1.57, Z=-3.217, P<0.001). All of the obtained images were sufficient for diagnosis. The CTDI vol, DLP, and E in LDCT were significantly lower than those in routine CT [(2.41±0.09), (10.53±1.03)mGy, Z=-6.568, P<0.001; (88.03±5.33), (338.74±34.64)mGy·cm, Z=-6.624, P<0.001; and (1.23±0.17), (4.74±0.48)mSv, Z=-5.976, P<0.001]. Conclusions:Patients with COVID-19 can be followed up with low-dose chest CT after discharge.

Objective To preliminary explore the feasibility of three‐dimensional transesophageal echocardiography ( 3D‐T EE) as images data source for 3D printing model by comparing the 3D‐T EE with CT of the aortic root Digital Imaging and Communications in M edicine ( DICOM ) data into 3D printing models respectively . Methods Fifteen patients w ho underwent surgical aortic valve replacement in the hospital were enrolled ,and the aortic root 3D‐T EE and CT DICOM data were obtained in perioperative . T he images were imported into M imics software to generate digital model standard tessellation language file ,and to print the aortic root models by 3D printer . T he structural morphology of both 3D‐T EE and CT models were qualitatively evaluated respectively . T he aortic annular area ,perimeter ,maximal diameter and minimal diameter of the original data , digital model , model and aortic valve replacement were quantitatively evaluated ,and the consistency of each parameter value were analyzed . T he mean diameter of 3D‐T EE and CT model were calculated . T he correlation of mean diameter with the number of replacement was analyzed . Results ①Both 3D‐TEE and CT images data were successfully printed into 3D models ,and the positive rate of aortic valve structure were 93 .3% ( 14/15) and 80 .0% ( 12/15) respectively . ②T he measured values of the aortic annular 3D‐T EE and digital model were smaller than CT ,CTdigital model and replacement ( P＜0 .05) ,and the measurement consistency among groups was high . ③ T he parameter values of 3D‐T EE model were smaller than CT model ( P ＜0 .05 ) ,and the measured values were all within the consistency range . T he mean diameters were highly correlated with the replacement values ( r ＞ 0 .95 , P ＜ 0 .05 ) . Conclusions 3D printing aortic root model based on 3D‐TEE image data is of high feasibility .

Objective: To summarize the clinical characteristics of 141 patients with novel coronavirus pneumonia (NCP) and the imaging characteristics of High Resolution CT(HRCT) in the chest. Methods: From January 20, 2020 to 28, 141 NCP patients, 77 males and 64 females, with a median age of 49 (9,87), were retrospectively analyzed. The clinical features, laboratory examination indexes and HRCT findings of 141 NCP patients were analyzed. Results: In 141 NCP patients, 38 (26.95%) had a decrease in leukocyte count and 71 (50.35%) had a decrease in lymphocyte ratio. Among 141 NCP patients, 139 (98.58%) had fever (over 37.5 ° C), 106 (75.18%) coughed, 11 (7.80%) had headache, 41 (29.08%) coughed up sputum, 93 (65.96%) had chest distress, and 4 (2.84%) had diarrhea. HRCT of 141 NCP patients were abnormal, 52 (36.88%) showed ground glass shadow (GGO) and patchy shadow, mainly subpleural distribution; 23 (16.31%) showed GGO with focal consolidation; 27 (19.15%) had small patchy blur; 20 (14.18%) had large patchy consolidation; 48 (34.04%) had bronchovascular bundle thickening and vascular perforator sign; 5 (3.55%) had Air bronchus sign; small nodule shadow in 7 cases (4.96%); fibrosis, grid shadow or strip shadow in 5 cases (3.55%); bilateral pleural effusion in 7 cases (4.96%); mediastinal or bilateral hilar lymphadenopathy in 4 cases (2.84%). Conclusions The clinical features and HRCT images of NCP are various. Under the specific epidemiological background of NCP, HRCT scan of chest should be carried out in time to make early warning of disease.

Objective: To understand the epidemiologic characteristics of fall in the elderly in Shanghai, as well as the differences between urban and rural areas, and provide evidence for targeted fall prevention and intervention. Methods: From January to March in 2017, a questionnaire survey was conducted in the elderly aged 60 or above selected from 7 urban communities and 6 rural communities in Shanghai to understand the epidemiologic characteristics of fall in the elderly and analyze the gender and urban-rural differences. Results: In urban area, a total of 3 386 elderly people were surveyed, in whom 441 (13.0%) had fall and 261 (7.7%) were injured after fall. In rural area, a total of 2 826 elderly people were surveyed, in whom 320 (11.3%) had fall and 169 (6.0%) were injured after fall. Fall risk in women were higher than that in men in both urban and rural areas with OR of 1.62 (95%CI: 1.42-1.86) and 1.16 (95%CI: 1.38-1.98) respectively, but the differences of fall related injury were not significant. Compared with urban areas, fall risk and fall related injury risk were both lower in rural areas with OR of 0.86 (95%CI: 0.73-0.99) and 0.74 (95%CI: 0.56-0.99). Compared with urban areas, men had lower risk for fall, and women had lower risk for fall related injury with OR of 0.68 (95%CI: 0.51-0.90) and 0.66 (95%CI: 0.47-0.93) respectively. Fall mainly occurred at home. Fall in urban area more frequently occurred on stairs, and fall in rural area more frequently occurred during farming. More than 60% of the falls had environmental risk factors. Slippery ground and uneven ground were main reasons. The incidence of fracture resulted from fall was high indicated by 89 fracture cases in urban areas (28.2%) and 64 fracture cases in rural areas (36.1%). Conclusions The risk for fall in Shanghai had gender and urban-rural differences. Targeted intervention should be conducted according to the characteristics of fall in the elderly.

Objective: To preliminary explore the feasibility of three-dimensional transesophageal echocardiography (3D-TEE) as images data source for 3D printing model by comparing the 3D-TEE with CT of the aortic root Digital Imaging and Communications in Medicine(DICOM) data into 3D printing models respectively. Methods: Fifteen patients who underwent surgical aortic valve replacement in the hospital were enrolled, and the aortic root 3D-TEE and CT DICOM data were obtained in perioperative. The images were imported into Mimics software to generate digital model standard tessellation language file, and to print the aortic root models by 3D printer. The structural morphology of both 3D-TEE and CT models were qualitatively evaluated respectively. The aortic annular area, perimeter, maximal diameter and minimal diameter of the original data, digital model, model and aortic valve replacement were quantitatively evaluated, and the consistency of each parameter value were analyzed. The mean diameter of 3D-TEE and CT model were calculated. The correlation of mean diameter with the number of replacement was analyzed. Results: ①Both 3D-TEE and CT images data were successfully printed into 3D models, and the positive rate of aortic valve structure were 93.3% (14/15) and 80.0% (12/15) respectively. ②The measured values of the aortic annular 3D-TEE and digital model were smaller than CT, CTdigital model and replacement (P<0.05), and the measurement consistency among groups was high. ③The parameter values of 3D-TEE model were smaller than CT model (P<0.05), and the measured values were all within the consistency range. The mean diameters were highly correlated with the replacement values (r>0.95, P<0.05). Conclusions 3D printing aortic root model based on 3D-TEE image data is of high feasibility.