Objective:To explore the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the microcirculatory perfusion of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.Methods:This study was an experimental study. Thirty-two male big ear white rabbits aged 6-8 months were assigned into electric burn group of 20 rabbits with high-voltage electric burns in the right lower limb and control group of 12 rabbits with sham injury in the right lower limb using the random number table method. At 0.5, 24.0, 48.0, and 72.0 h post injury, the lower limbs of rabbits in the two groups underwent axial fast spin echo T1-weighted imaging, fast spin echo T2-weighted imaging, and DCE-MRI examination. A reference region-based hemodynamic model was applied to obtain the blood perfusion parameters of skeletal muscle in the injured limbs, including the volume transfer constant K trans value and rate constant K ep value. The skeletal muscle tissue from the electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury and the control group of rabbits at 0.5 h post injury was harvested for immunohistochemical staining to observe the microvascular changes and calculate the microvascular density (MVD). The correlation between the K trans and K ep values and the MVD of skeletal muscle tissue in electric burn group of rabbits at 0.5-72.0 h post injury was analyzed. The number of samples was 5 in the electric burn group, and the number of samples was 3 in the control burn group. Results:From 0.5-72.0 h post injury, the K trans and K ep values in skeletal muscle tissue of electric burn group of rabbits exhibited the trends of increase first and decrease then, both of which reached peak values at 24.0 h post injury. The K trans values at 0.5, 24.0, 48.0, and 72.0 h post injury (with t values of -15.77, -14.91, -40.35, and -40.25, respectively, P<0.05) and the K ep values at 0.5, 24.0, and 48.0 h post injury (with t values of -5.39, -6.82, and -6.83, respectively, P<0.05) in skeletal muscle tissue in electric burn group of rabbits were significantly higher than those in control group. The MVD in skeletal muscle tissue in control group of rabbits at 0.5 h post injury and in electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury was (24.7±3.5), (21.8±2.2), (40.8±9.1), (16.4±2.4), and (9.8±0.8) per mm2, respectively. The MVD in skeletal muscle tissue in electric burn group of rabbits at 24.0 h post injury was significantly higher than that in control group at 0.5 h post injury ( t=2.89, P<0.05), and the MVD in skeletal muscle tissue at 48.0 and 72.0 h post injury was significantly lower than that in control group at 0.5 h post injury (with t values of 4.01 and 9.52, respectively, P<0.05). The K trans and K ep values of skeletal muscle tissue in rabbits in electric burn group were significantly positively correlated with microvascular density at 0.5 to 72.0 h post injury (with both r values of 0.95, P<0.05). Conclusions:The quantitative perfusion parameters K trans and K ep values of DCE-MRI can effectively reflect the microcirculatory perfusion changes of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.

Objective:To explore the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the microcirculatory perfusion of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.Methods:This study was an experimental study. Thirty-two male big ear white rabbits aged 6-8 months were assigned into electric burn group of 20 rabbits with high-voltage electric burns in the right lower limb and control group of 12 rabbits with sham injury in the right lower limb using the random number table method. At 0.5, 24.0, 48.0, and 72.0 h post injury, the lower limbs of rabbits in the two groups underwent axial fast spin echo T1-weighted imaging, fast spin echo T2-weighted imaging, and DCE-MRI examination. A reference region-based hemodynamic model was applied to obtain the blood perfusion parameters of skeletal muscle in the injured limbs, including the volume transfer constant K trans value and rate constant K ep value. The skeletal muscle tissue from the electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury and the control group of rabbits at 0.5 h post injury was harvested for immunohistochemical staining to observe the microvascular changes and calculate the microvascular density (MVD). The correlation between the K trans and K ep values and the MVD of skeletal muscle tissue in electric burn group of rabbits at 0.5-72.0 h post injury was analyzed. The number of samples was 5 in the electric burn group, and the number of samples was 3 in the control burn group. Results:From 0.5-72.0 h post injury, the K trans and K ep values in skeletal muscle tissue of electric burn group of rabbits exhibited the trends of increase first and decrease then, both of which reached peak values at 24.0 h post injury. The K trans values at 0.5, 24.0, 48.0, and 72.0 h post injury (with t values of -15.77, -14.91, -40.35, and -40.25, respectively, P<0.05) and the K ep values at 0.5, 24.0, and 48.0 h post injury (with t values of -5.39, -6.82, and -6.83, respectively, P<0.05) in skeletal muscle tissue in electric burn group of rabbits were significantly higher than those in control group. The MVD in skeletal muscle tissue in control group of rabbits at 0.5 h post injury and in electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury was (24.7±3.5), (21.8±2.2), (40.8±9.1), (16.4±2.4), and (9.8±0.8) per mm2, respectively. The MVD in skeletal muscle tissue in electric burn group of rabbits at 24.0 h post injury was significantly higher than that in control group at 0.5 h post injury ( t=2.89, P<0.05), and the MVD in skeletal muscle tissue at 48.0 and 72.0 h post injury was significantly lower than that in control group at 0.5 h post injury (with t values of 4.01 and 9.52, respectively, P<0.05). The K trans and K ep values of skeletal muscle tissue in rabbits in electric burn group were significantly positively correlated with microvascular density at 0.5 to 72.0 h post injury (with both r values of 0.95, P<0.05). Conclusions:The quantitative perfusion parameters K trans and K ep values of DCE-MRI can effectively reflect the microcirculatory perfusion changes of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.

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 explore the management strategies for patients with gynecological malignant tumors during the outbreak and transmission of COVID-19.Methods:We retrospectively analyzed the clinical characteristics, treatment, and disease outcomes of three patients with gynecological malignancies associated with COVID-19 in Renmin Hospital of Wuhan University, and proposed management strategies for patients with gynecological tumors underriskof COVID-19.Results:Based on the national diagnosis and treatment protocol as well as research progress for COVID-19, three patients with COVID-19 were treated. Meanwhile, they were also appropriately adjusted the treatment plan in accordance with the clinical guidelines for gynecological tumors. Pneumonia was cured in 2 patients, and one patient died of COVID-19.Conclusions:Patients with gynecological malignant tumors are high-risk groups prone to COVID-19, and gynecological oncologists need to carry out education, prevention, control and treatment according to specific conditions. While, actively preventing and controlling COVID-19, the diagnosis and treatment of gynecological malignant tumors should be carried out in an orderly and safe manner.

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.

Purpose To investigate the reproducibility and risk factors of aortic distensibility quantification in patients with abdominal aortic aneurysm using multi-slice spiral CT.Materials and Methods The abdominal aortic computed tomography angiography data of 54 patients with infrarenal abdominal aortic aneurysm were prospectively studied.64-muti detector spiral CT,retrospective ECG-gating and segment data collecting scanning were all carried out.The aortic distensibility,D value,and pulse wave velocity at renal artery level and infrarenal artery level were calculated using semiautomatic segmentation software.The difference of aortic distensibility at different levels was compared,and consistency test was performed.Results The D value at renal artery level and infrarenal artery level of abdominal aortic aneurysm was (1.05 ±0.22)×10-5/Pa and (0.49± 0.18)× 10-5/Pa,respectively;and the corresponding pulse wave velocity was (9.68± 1.09) m/s and (14.96 ±4.01) m/s,respectively.The intraclass correlation coefficient of intra-and interobserver at renal level was 0.92 and 0.79,while it was 0.85 and 0.79 at inffa level.The Bland-Altman graph showed that the vast majority of points were within the 95％ CI,the difference of intraobserver between the two positions was 0.017×105/pa and 0.010×10-5/Pa,and the difference of interobserver was 0.013×105/Pa and 0.018×10-5/Pa.Multivariate analysis of all these variables showed aortic distensibility to be independently correlated to body mass index,pulse pressure,diastolic pressure and abdominal aortic aneurysm diameter (R2=0.68).Conclusion The quantification of aortic distensibility using multi-slice spiral in patients with abdominal aortic aneurysm shows high stability.Taking into consideration of the relationship between different risk factors and the incidence of abdominal aortic aneurysm can lead to a better clinical approach.

Objective To investigate the effect of inversion time (TI) on flow-sensitive alternating inversion recovery (FAIR) perfusion imaging of spinal bone marrow (SBM),and evaluate the reproducibility of blood flow (BF) measurements using this technique.Methods Twenty four healthy volunteers without lumbar and other disease with clinical and MR studies were prospectively included.The first 14 healthy volunteers were included to study the effect of TI on ASL perfusion imaging of SBM to get the optimized TI,the remaining 10 volunteers were included to investigate the reproducibility of the SBM arterial spin labeling (ASL) scan protocol.The optimized TI of FAIR spinal bone marrow perfusion experiment was carried out on 14 healthy volunteers on 3.0 T magnet,two adjacent vertebral bodies were orderly selected from each volunteer to measure the △M and the SNR of FAIR perfusion MRI with 5 different TIs (800,1 000,1 200,1 400,1 600 ms),and the vertebral bodies selected order were determined by the order of the subjects enrolled.In addition,FAIR perfusion spinal vertebral BF measurements were repeated in last l0 healthy subjects on L4 or L5 by reposition immediately,paired t test and reproducibility statistics (included within-patient standard deviation (wSD) and within-patient coefficient of variation (WCV)) were used to analyze the test-retest experiment reproducibility.Result TI optimization experiments total included 28 vertebral bodies,when TI (ms) was chose as 800,1 000,1 200,1 400,1 600,ms respectively,the mean △M of spinal bone marrow were 20.8±9.0,29.0± 10.9,36.4± 12.5,26.2± 10.2 and 23.8± 11.5,and the mean SNR were 2.0± 1.0,2.3±0.8,2.4± 1.0,2.3±0.8 and 2.0±0.7.With TI increasing,AM and SNR increased first and then decrcascd,the maximum values of both were achieved when the TI near 1 200 ms.Test-retestexperimcnt were carried on 10 vertebral bodies eventually,and two measurements of spinal vertebral BF perfusion before and after were (108.9±4.6)and (109.2 ±4.6)ml · 100g-1· min 1,respectively,and no significant difference was found (t=-0.157,P=0.879),wCV of the measurements was 3.28％ (3.57/109.06).Conclusion The optimal TI was 1 200 ms for spinal bone marrow ASL perfusion image,at which the maximum AM,higher SNR,and good reproducibility for the FAIR spinal bone marrow perfusion imaging can be achieved.

Objective To explore the feasibility to diagnose ureterolithiasis by 16-multidetector spiral computed tomography (16-MDCT) at different low doses based on body mass index (BMI).Methods A total of one hundred patients from 2009 Sep to 2010 Feb suspected of ureterolithiasis were randomly divided into 2 equal groups undergoing 16-MDCT at standard-dose (120 kV, 240 mA) or lowdose (120, 80, and 50 mA, respectively) based on the body mass index (BMI).Taking the clinical diagnosis as the standard, the sensitivity level, specificity level, and positive predictive value of these groups were compared.Results The dose length product ( DLP ) of the low-dose CT group and the average CT dose index (CTDIvol ) were 18.95 and 6.65 mGy, respectively.There was significant difference between the two groups ( t = 31.78, P ＜ 0.01 ).The sensitivity level, specificity level, and positive predictive value of the low-dose group were 97.1% , 94.0% , and 94.3% , respectively, all not significantly different from those of the standard-dose groups (97.3% , 96.0% , and 97.3% , respectively,P ＞0.05).Conclusions It is feasible to diagnose ureterolithiasis by low-dose 16-MDCT based on BMI with the obtained image quality meeting the clinical diagnostic requirements.