Objective To assess the usefulness of combined dual-energy CT pulmonary angiography (DE-CTPA) and indirect CT venography (CTV) in the diagnosis of venous thromboembolism (VTE).Methods Forty-nine patients with leg swelling suspected of pulmonary embolism (PE) underwent both DE-CTPA combined with CTV and lower extremity venous ultrasound (US) in 1-2 days prior to CT.Image quality of CTPA and dual energy lung perfusion image (DEPI) was rated using a 5-point scale and the coherence between CTPA and DEPI was analyzed by Kappa statistics.The ability of CTV and US in the diagnosis of deep venous thrombosis (DVT) was compared by Chi-square test.Results Twenty-nine of 49 patients were identified with PE by DE-CTPA,including 28 patients identified by CTPA and one more by DEPI,and 21 patients were found to have both PE and DVT.Both DE-CTPA and DEPI had positive findings for pulmonary embolism in 19 patients and both had negative findings in 18 patients.There was a moderate agreement between DEPI and DE-CTPA in the assessment of PE (Kappa value =0.7534).Thirty-eight patients with DVT were identified by US,while 35 patients were identified by CTV.Among the 35 patients with DVT identified by CTV,pelvic veins were involved in 25 patients,while the inferior vena cava was involved in 3 patients.There was no significant difference between CTV and US in the diagnosis of DVT(P =0.625).The detection rate of VTE with DE-CTPA combining CTV was 30.6％ higher than that with CTPA alone.Conclusions The combined DE-CTPA and CTV achievesone-stop examination.It not only provides evaluation of PE and DVT and increases detection of VTE,but also depicts perfusion defect of pulmonary parenchyma that corresponds to PE.

Objective To compare the differences in radiation doses from CT scanning between children of different age groups and adult patients by using both traditional radiation dose assessment parameters and size-specific dose estimates (SSDE).Methods A total of 406 patients undergoing lung CT examination were studied.They were sampled retrospectively and continuously from the Union Hospital and divided into six groups by age distritution (0-2,3-6,7-10,11-14,15-18,＞18 years old).The CTDIvol and DLP values were randomly sampled using MATLAB platform-based dicom data software.The SSDE and water equivalent diameter were also calculated according to the AAPM 220 Report.The differences in radiation doses from lung CT scaning between children and adult patients were analysed.Results The CTDIvol values for all age groups were significantly lower than the SSDE values.The differences were statistically significant (t =-36.36,-32.83,-30.36,-28.74,-23.89,P＜0.05).The SSDE values were 137％,94％,79％,57％ and 42％ higher than the CTDIvol values,respectively.The CTDIvol values for the adult group were also lower than the SSDE values,and the difference was statistically significant (t=-21.92,P＜0.05),and the SSDE value was about 41％ higher than the CTDIvol value.With the increased age,CTDIvol value,DLP value,Dw value and SSDE value for children of all age groups gradually increased and were significantly smaller than those for the adult group.The difference was statistically significant (F=63.39,203.28,89.27,103.44,P＜0.05).The conversion coefficient f for all age groups decreased significantly with age,which was significantly higher than that for the adult group,and the difference was statistically significant (F =109.83,P ＜ 0.05).Conclusions In lung CT scanning,the CTDIvol value significantly underestimated the radiation doses to children as compared to adults.CTDIvol values are more easily underestimated for younger patients.The SSDE method allows for more accurate reflection of the radiation doses to different patients,taking into account differences in the examined patient size.

The clinical application of 16-slice CT coronary angiography (CTCA) and the impact of plaques differently characterized on assessing coronary artery stenosis were evaluated. Thirty-eight patients with coronary artery disease diagnosed by conventional coronary angiography (CAG) un- derwent 16-slice CTCA (collimation: 16×0.75 mm; rotation time: 420 msec; kernel: 35f; effective current: 500 mAs; tube voltage: 120 kV). The interval between CTCA and CAG was within one month. CTCA was evaluated by consensus of two independent experienced radiologists unknowing CAG findings. Original images, maximum intensity projections and multiplanar reconstructions were used to assess coronary artery stenosis. For a determined plaque an attenuation value≥130 HU was considered as calcified, and ＜130 HU noncalcified. The plaques were then classified into significant calcification (extensive calcification), medium calcification (small isolated calcification) and noncal- cification. The diagnostic accuracy of 16-slice CTCA findings as well as to detect ≥50% stenoses caused by plaques was evaluated respectively regarding CAG as the standard of reference. In com- parison with CAG findings, the sensitivity, specificity, positive and negative predictive value derived from CTCA for mild stenosis (＜50%) were 72.7%, 38.5%, 50%, 62.5%, respectively; for moderate stenosis (50%-75%) 82.4%, 72.7%, 70%, 84.2%, resepctively; and for severe coronary stenosis (＞75%) 85%, 90.5%, 81%, 92.7% respectively. With the increase of stenoses degree, the value of CTCA was greater. For the classification of the plaque calcification with ≥50% stenosis CTCA at- tained the sensitivity, specificity, positive and negative predictive value for severe calcificatoin 73.3%, 22.2%, 61.1% and 33.3%, respectively; for moderate calcification 70%, 55.6%, 63.6% and 62.5%, respectively; for noncalcification 93.8%, 85.7%, 93.8% and 85.7% respectively. CTCA was restricted in assessing coronary artery stenosis in the presence of calcification, but CTCA value was much im-proved in assessing non-calcified stenosis. It was concluded that 16-slice CTCA could provide useful information about coronary artery stenosis, especially for severe stenosis (≥50%) and non-calcified plaque. Since CTCA is a noninvasive technique, it may be useful in screening coronary artery dis-ease.

Objective:To assess the clinical application of bedside X-ray photography assistor (Patent No. 202 023 219 898.1) in neonatal bedside photography.Methods:From April 2021 to February 2022, a total of 180 pediatric patients were selected who underwent bedside chest X-ray photography in neonatal intensive care unit (NICU) of Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology. These patients were divided into contrpol group, consisting of 48 males and 42 females aged at (3.3 ± 2.0) d (0-10 d), and experimental group, including 50 males and 40 females aged (3.1±2.2) d (0-12 d). For chest photography, routine workflow was followed in the control group while in experimental group bedside photography protection and body position fixing device was used. The examination time, reshoot rate and image quality were compared between the two groups.Results:The diagnostic physician score and patient comfort score in the experimental group were higher than those in the control group, with statistically significant differences ( t = 3.98, 3.82, P < 0.001). The success rate in the experimental group was higher than that in the control group, with statistically significant difference ( χ2= 7.84, P < 0.05). The average time of examination in the experimental group was not significantly different from in the control group ( P>0.05 ). Conclusions:The application of bedside X-ray photography assistor in neonatal bedside photography can significantly improve the success rate and image quality and reduce the radiation dose to pediatric patients without significantly increased examination time, which is worthy of clinical application and promotion.

Objective To explore the application value of virtual monochromatic imaging combined with adaptive statistical iterative reconstruction (ASIR) and automatic spectral imageing mode selection(ASIS) in reducing the radiation dose and contrast dose of CT portal venography.Methods We retrospectively collected 120 cases (80 males and 40 females) who underwent upper abdominal enhancement CT from January 2017 to April 2017.Patients were divided into 3 groups (40 cases in each group) according to the scanning program.Group A used conventional 120 kVp scan,NI =10,contrast agent dosage was 450 mgI/kg of body weight,image was reconstructed with 50％ ASIR technique;Groups B and C used spectral CT mode,NI =10 (Group B),NI =13 (Group C),the amount of contrast agent was 300 mgI/kg of body weight,and the image was reconstructed with 60 keV +50％ ASIR.One-way analysis of variance was used to compare the mean CT values and their differences,image noise,SNR and CNR of portal vein and liver parenchyma in three groups of images.Subjective image quality scores were performed on three groups of images by two senior radiologists.The patient's CTDIvol,DLP were recorded and the E was calculated.Results The amount of contrast agent in group B and C was reduced by about 30％ compared with group A.The portal vein CT values of groups A,B,and C were 168.22± 17.82,209.06±20.07,and 211.03±25.60.The portal vein CT values of group B and C were significantly higher than those of group A,respectively (t =-9.625,-8.680,P ＜ 0.05).The CT value difference between portal vein and liver parenchyma was 60.01± 17.01,106.63±25.83,107.72±25.39,respectively.SNRs were 8.48±1.41,12.64±2.94,10.77±1.94,and CNR were 5.16±1.80,8.13±2.54,7.32±1.84,respectively.The image quality scores were 3.53±0.68,4.75±0.54 and 4.53±0.64,respectively.The CT value difference,SNR,CNR and image quality scores of group B and group C were significantly higher than those in group A(t=-9.536,-9.857,-8.082,-6.064,-6.050,-5.308,-8.912,-6.779,P＜0.05).The CTDIvolof groups A,B and C were (12.15±5.02) mGy,(12.34±4.18) mGy,(10.03±3.13) mGy,DLP were (348.62± 155.99) mGy· cm,(355.56± 131.07) mGy·cm,(287.10±92.25) mGy·cm,respectively,E were (5.23±2.34) mSv,(5.33±1.97) mSv,(4.31±.1.38) mSv,compared with the A and B groups,the CTDI,ol,DLP and E of the C group were significantly lower(t=2.274,2.147,2.147,2.812,2.702,2.702,P＜0.05),and CTDIvol,DLP and E were decreased by 19％.Conclusions In CT portal venography,NI =13,60 keV combined with 50％ ASIR reconstruction and ASIS can be used to personalize the contrast dose and radiation dose of the patient and provide images that meet the diagnostic requirements.

Objective To evaluate the diagnose value of nonenhanced electrocardiogram (ECG)?gated quiescent?interval single?shot MR angiography (QISS MRA) in lower extremity arterial stenosis. Methods A retrospective analysis of 30 patients with lower extremity ischemic manifestations and concurrent lower extremity arterial CTA and QISS MRA was performed from April to December 2017 at the Union Hospital of Tongji Medical College, Huazhong University of Science and Technology. All patients underwent CTA and ECG?gated non?contrast?enhanced QISS MRA. The entire lower extremity arteries were divided into 19 segments (lower abdominal aorta, common iliac artery, internal iliac artery, external iliac artery, superficial femoral artery, deep femoral artery, radial artery, anterior tibialis anterior tibial artery, posterior tibial artery, radial artery). Two radiologists scored QISS MRA and CTA image quality using a 4?point scale and assessed the severity of arterial stenosis. Kappa analysis was used to evaluate the degree of stenosis of different examination methods in the same patient and the consistency of the scores of different radiologsts in the same patient. Result A total of 570 vessel segments were collected from 30 patients. The image quality of 560/570 (98.2%) and 548/570 (96.1%) of radiologist 1 was rated as excellent or good by CTA and QISS?MRA (grades 3 and 4), and 561/570 (98.4% of radiologist 2) The image quality of the segment and the 544/570 (95.4%) segment were rated as excellent or good by CTA and QISS?MRA, respectively. The image quality scores of radiologist 1 to CTA and QISS MRA were (3.87±0.38) and (3.70± 0.53), respectively, and radiologist 2 were (3.86±0.40) and (3.68±0.54) respectively. On the QISS?MRA, only 7 of the 570 segments (1.2%, 7/570) obtained images that could not satisfy the diagnostic image quality. The two radiologists used CTA and QISS MRA to evaluate the consistency of different degrees of vascular stenosis. The radiologist 1 evaluated the Kappa value of CTA and QISS MRA between 0.714 and 0.939 for different degrees of vascular stenosis. Radiologist 2 had a Kappa value of 0.603 to 0.939. QISS MRA was used to evaluate the consistency of vascular stenosis in different segments between the two radiologists. The Kappa value ranged from 0.813 to 0.933. Conclusion QISS?MRA is of great value in the diagnosis of lower extremity arterial stenosis.

Objective:To investigate the value of the size-specific dose estimate (SSDE) on dose estimations of children's head CT scans.Methods:A retrospective study was conducted on plain head CT scans of 252 patients with the 64-row detector CT device of Discovery 750HD in the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from January to September in 2019. The volume CT dose index (CTDI vol)values were recorded. The head circumference (HC), area, and CT value were measured using a self-developed computer program, and the water equivalent diameter (WED), size-specific conversion factors ( f293 and f220), and absorbed dose (SSDE 293 and SSDE 220) were calculated according to the AAPM reports 293 and 220.The patients were divided into three groups by the quartering meth odaccording to their HC(<47.8 cm, 47.8-52.7 cm, >52.7 cm)and four groups based on their ages(0-2, 3-6, 7-10 and 11-14 years old). The difference between parameters ( f220 and f293, SSDE 220 and SSDE 293、SSDE 293 and CTDI vol) were compared for different groups, and the correlation of HC with f293 and SSDE 293 was analyzed. Results:There was an overestimation of f220 by 11.11% ( t=252.61, P<0.05) compared with f293. SSDE 220 was overestimated by 10.31% ( t=228.21, P<0.05) compared with SSDE 293, and SSDE 293 was underestimated by 9.60% ( t=-31.34, P<0.05)compared with CTDI vol. For the three HC groups, SSDE 220 was overestimated by 8.54%, 10.37%, and 11.57% ( t=73.73, 438.58, 275.52, P<0.05)compared with SSDE 293, and SSDE 293 was underestimated by 1.30%, 9.79%, and 14.61% ( t=-1.91, -60.95, -47.64, P<0.05)compared with CTDI vol. For the four age groups SSDE 220 was overestimated by 8.45%, 10.00%, 10.57%, and 11.36% ( t=63.58, 232.29, 247.84, 302.95, P< 0.05)compared with SSDE 293, and SSDE 293 was underestimated by 1.49%, 8.27%, 10.63%, and 13.78% ( t=-1.83, -28.27, -37.30, -49.80, P< 0.05)compared with CTDI vol. Furthermore, HC was highly correlated with f293 and SSDE 293 ( r2=0.88 and 0.76, respectively, P< 0.05). Conclusions:The radiation dose in children′s head CT scanning can be more accurately estimated according to the AAPM Report 293, while it can be overestimated by CTDI vol. Meanwhile, the CT radiation dose can be patently overestimated with the AAPM Report 220 compared with Report 293.HC is closely correlated with f293 and SSDE 293 and it can be used to estimatee more accurately for SSDE and the radiation dose received by children during head CT scanning.

Objective:To study the feasibility that using size-specific dose estimation (SSDE) to estimate organ dose and effective dose in coronary CT angiography (CTA).Methods:Totally 421 consecutive patients with coronary artery CTA were included and retrospectively analized. All patients were scanned using the 3rd generation dual-source Force CT with prospectively ECG gated axis scan mode. The size specific dose estimation(SSDE) for each patient was conducted by calculate water equivalent diameters with Radimetrics. The organ doses of heart, lung, liver and breast, were estimated with Monte Carlo method. Patient-specific effective dose was calculated as a weighted sum of simulated organ doses with the coefficients from ICRP 103. Linear correlation analysis was used to validate the relationship between SSDE and organ doses as well as effective dose, and to derive coefficients for patient specific dose estimation. The mean error rate was used to evaluate estimation accuracy.Results:The CTDI vol, SSDE and effective dose were (16.8±8.7)mGy, (20.8±8.8)mGy and (4.4±2.9)mSv, respectively. The linear fitting formula for estimating organ dose based on SSDE were: Y=1.2 X-6.4 ( R2=0.91, P<0.05, mean error 0.1%) for heart, Y=1.4 X-7.4 ( R2=0.91, P<0.05, mean error 7.9%) for breast, Y=0.89 X-4.6 ( R2=0.86, P<0.05, mean error 8.3%) for lung, and Y=0.36 X-1.8 ( R2=0.64, P<0.05, mean error -17.9%) for liver. The linear fitting formula for estimating the individual effective dose based on SSDE were: Y=0.21 X-1.2 ( R2=0.92, P<0.05, mean error 0.2%) for men, Y=0.39 X-2.2 ( R2=0.93, P<0.05, mean error 1.7%) for women. Conclusions:In coronary artery CTA, the absorbed dose of the organs and patient specific effective dose could be estimated with SSDE and the corresponding conversion coefficients, which will help to achieve personalized assessment and precise management of patient radiation dose and risk in clinical practice.

Objective:To survey and supervise the risk of infection control and radiation safety in the radiological diagnostic workplace for COVID-19, and provide data support for the safety protection of radiographers and related staff.Methods:4 emergency hospitals for COVID-19 including 2 makeshift hospitals, module hospital and brick pattern hospital in Hubei province were performed for testing and evaluation of imaging performance and radiological protection for the 8 new installed CT scanners and places according to the national standards of WS 519-2019 and GBZ 130-2013. The infection control safety factors such as the layout of the equipment room were monitored and investigated. Two COVID-19 designated hospitals including general hospital and infectious disease specialized hospital were selected to carry out field investigation and sampling of environmental biological samples for 4 CT rooms. Then the samples were detected for the nucleic acid of novel coronavirus. The results of radiodiagnostic workplace overall arrangement, infection prevention and the nucleic acid testing were analyzed, and the biological safety reliability and risk point were evaluated.Results:The indicators of imaging performance and radiation protection for 8 CT scanners in emergency hospitals could meet the requirements of national standards.Each of 2 makeshift hospitals had 3 CT rooms with the area of 38.8 m 2 and 4 mm Pb equivalent thickness of protective shielding. The CT rooms in module hospital and brick pattern hospital were 20.0 m 2, and 35.8 m 2 in areas, with 4 mm Pb equivalent and 3 mm Pb equivalent thickness of protection shielding, respectively. The 8 radiological diagnostic workplaces of the emergency hospitals were designed and constructed based on " three zones with two passage ways" . The result of the nucleic acid test indicated that the positive samples were found at the multiple sites such as scanning bed, internal of gantry and ground touched by patients in CT scanning room. The areas such as console panel and ground were risked of pollution by the virus infected hands and feet of radiographers. In addition, the similar positive samples were found in the areas in scanning room with no touch of patients, such as observation window and air outlet. Conclusions:8 CT scanners and rooms in 4 emergency hospitals basically meet the requirements of imaging performance and radiation protection. The disinfection of COVID-19 radiodiagnostic workplace should be standardized.