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 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 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 compare the image quality of turbo gradient and spin echo-BLADE diffusion weighted imaging (TGSE-BLADE-DWI) with that of readout segmentation of long variable echo-trains (RESOLVE) at the sellar region.Methods:From September 15 th, 2019 to February 15 th, 2020, 38 patients with suspected sellar abnormalities were enrolled prospectively to perform RESOLVE and TGSE-BLADE-DWI at a 3.0 T MR scanner in Department of Radiology, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology. Totally, 32 patients were identified with sellar lesions. The DWI images were evaluated subjectively and objectively. Two experienced radiologists scored images of the two DWI methods for anatomical structures (including the internal carotid arteries, optic chiasm, pituitary stalk and pituitary gland), lesion conspicuity, susceptibility artifacts, geometric distortions and overall image quality using a five-point scale respectively. Objective parameters on the images of the two DWI methods were analyzed, including lesion size, signal to noise ratio (SNR) and apparent diffusion coefficient (ADC). The consistency of subjective scores of two radiologists was tested by Kappa test. Paired t-test, Wilcoxon signed rank test, Kappa statistics were used for statistical evaluation. Results:TGSE-BLADE-DWI performed significantly better than RESOLVE in depicting the sellar anatomical structures, lesion conspicuity, geometric distortion and overall image quality (all P<0.05). There were no significant differences in SNR, maximum longitudinal diameter of lesions and ADC of lesions between the two DWI methods(all P>0.05). The maximum transverse diameter measured by TGSE-BLADE-DWI was significantly smaller than that of RESOLVE ( Z=3.31, P=0.001). Conclusions:Compared with RESOLVE, TGSE-BLADE-DWI is superior in depicting the anatomical structures, decreasing susceptibility artifacts and geometric distortions at the sellar region and effectively improves the image quality of DWI, which has great value in clinical applications.

Objective:To explore the value of monoenergetic imaging on dual-layer spectral detector CT combined with individual injection protocol of contrast medium in brain CT angiography (CTA).Methods:Seventy-six patients who underwent brain CTA on the Philips IQon dual-layer spectral detector CT and individual injection protocol of contrast medium in Union Hospital of Tongji Medical College, Huazhong University of Science and Technology from August to November 2020 were retrospectively analyzed. Objective and subjective evaluation of image quality was performed in conventional energetic images (conventional group) which derived from 120 kVp hybrid iterative reconstruction algorithm and 50 keV virtual monoenergetic images (test group) which derived from spectral reconstruction algorithm. The objective evaluation content included CT values, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of internal carotid artery and middle cerebral artery, CT values and standard deviation (SD) of brain parenchyma. The subjective evaluation was completed by two senior radiologists according to the 5-point scale, and the inter-agreement between two radiologists was evaluated by Kappa test. Paired t test or Wilcoxon rank test was used for analysis between two groups. Results:The SNR and CNR of both internal carotid artery and middle cerebral artery, as well as CT values of internal carotid artery, middle cerebral artery and brain parenchyma, were significantly higher in test group than that in conventional group (all P<0.001). The subjective scores of two radiologists for test group were both 5 (5, 5) points, and the subjective scores for conventional group were both 4 (4, 4) points. The subjective scores of the radiologists were in good agreement, and the Kappa values were 0.74 and 0.84 respectively. The subjective scores of test group were significantly higher than that of conventional group ( Z=-11.15, P<0.001). Conclusion:Monoenergetic imaging on dual-layer spectral detector CT combined with individual injection protocol of contrast medium can improve SNR, CNR and the image quality of brain CTA.

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.

Objective:To investigate the clinical value of third-generation dual-source CT with high pitch, 70 kV combined with 16 ml contrast agent in low radiation dose imaging of pulmonary embolism (PE).Methods:Eighty-three patients with suspected PE underwent CT pulmonary angiography were randomly divided into two groups: group A with 36 cases, 100 kV, 1.0 pitch, and 60 ml contrast agent; group B with 47 cases, 70 kV, 2.2 pitch, and 16 ml contrast agent. The volume CT dose index and dose length product of the two groups were recorded to calculate the effective dose E, and the CT values of enhanced pulmonary arteries, background noise, and muscles values were recorded to calculate signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The overall image quality and the beam-hardening artifact of superior vena cava were subjectively evaluated on a 3-point scale. Results:There were no significant differences in gender, age, height, weight, BMI, proportion of PE, and CT values of enhanced pulmonary arteries at all levels ( P>0.05). The value E of group B was (0.76±0.13) mSv, significantly lower than that in group A [(1.91±0.54) mSv, Z=-5.23, P<0.001]. Although background noise of group B was significantly higher than that of group A ( Z=-4.99, P <0.001), SNR and CNR values of group B were significantly lower than those of group A ( Z=-4.56, -4.48, P<0.001), there was no statistically significant difference in the overall image quality scores between the two groups ( P>0.05). The beam-hardening artifact caused by superior vena cava in group B was significantly lower than that in group A ( Z=-5.15, P <0.001). Conclusions:The third generation dual-source CT with high pitch, 70 kV combined with 16 ml contrast agent can significantly reduce the interference of contrast agent beam-hardening artifact on the right and right superior pulmonary arteries to ensure the diagnostic image quality of PE, and effectively reduce radiation dose by 60% and total volume of contrast agent by 73%.

Objective:To investigate the application value of third-generation dual-source CT(3-G DSCT) low-dose scan mode combined with iterative reconstruction technology in the screening of COVID-19 and to evaluate the radiation dose.Methods:One hundred and twenty patients suspected of COVID-19 from December 2019 to February 2020 were retrospectively analysed and randomly divided into two groups (test group and conventional group, 60 patients in each). The parameters for test group included 3-G DSCT, Turbo Flash scan mode, CARE kV, with reference 90 kV, pitch 2.0, and ADMIRE algorithm, while those parameters for conventional group included the 128-slice CT, conventional spiral scan mode, 120 kV, pitch 1.2, and FBP algorithm. The CT values of aorta, spinal posterior muscle, and subcutaneous fat, the aortic noise, signal-to-noise ratio (SNR), and contrast noise ratio (CNR) were compared to evaluate the image quality between two groups. Two experienced doctors scored the image quality using a double-blind method, and compared the CT dose index volume (CTDI vol), dose-length product (DLP), and effective dose ( E) of the two groups. Results:The CT value of the aorta and spinal posterior muscle and the aortic SNR in the test group were (45.38±4.77), (53.41±8.44) HU, and 2.82±0.59, and significantly higher than those in the conventional group [(39.68±6.26), (42.66±6.32) HU, 2.58±0.61, t=5.608, 7.897, 2.162, P<0.05]. The aortic noise, CNR and subjective scores between the two groups had no significant difference( P>0.05). The CTDI vol, DLP, and E in the test group were (3.09±1.02) mGy, (107.57±32.81) mGy·cm, (1.51±0.46) mSv, significantly lower than those in the conventional group [(7.00±1.80) mGy, (261.65±73.93) mGy·cm, (3.66±1.03) mSv; t=-14.680, -14.756, -14.756, P<0.05]. Conclusions:In the screening of COVID-19, using low-dose scanning mode of 3-G DSCT combined with iterative reconstruction technology would provide diagnostic quality images and meanwhile effectively reduce the radiation dose and improve the SNR of the image.