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To investigate the computed tomography (CT) characteristics and differential diagnosis of high altitude pulmonary edema (HAPE) and COVID-19, CT findings of 52 cases of HAPE confirmed in Medical Station of Sanshili Barracks, PLA 950 Hospital from May 1, 2020 to May 30, 2020 were collected retrospectively. The size, number, location, distribution, density and morphology of the pulmonary lesions of these CT data were analyzed and compared with some already existed COVID-19 CT images which come from two files, "Radiological diagnosis of COVID-19: expert recommendation from the Chinese Society of Radiology (First edition)" and "A rapid advice guideline for the diagnosis and treatment of 2019 novel corona-virus (2019-nCoV) infected pneumonia (standard version)". The simple or multiple ground-glass opacity (GGO) lesions are located both in the HAPE and COVID-19 at the early stage, but only the thickening of interlobular septa, called "crazy paving pattern" belongs to COVID-19. At the next period, some increased cloudy shadows are located in HAPE, while lesions of COVID-19 are more likely to develop parallel to the direction of the pleura, and some of the lesions show the bronchial inflation. At the most serious stage, both the shadows in HAPE and COVID-19 become white, but the lesions of HAPE in the right lung are more serious than that of left lung. In summary, some cloudy shadows are the feature of HAPE CT image, and "crazy paving pattern" and "pleural parallel sign" belong to the COVID-19 CT, which can be used for differential diagnosis.

Objective: Sparse-view CT has the advantages of accelerated data collection and reduced radiation dose, but data missing arising from the data collection process causes serious streaking artifact and noise in the images reconstructed using the traditional filtering back projection algorithm (FBP). To solve this problem, we propose a multi-scale wavelet residual network (MWResNet) to restore sparse-view CT images., Methods: The MWResNet was based on the combination of deep learning and traditional model in MWCNN, and the wavelet network was combined with the residual block to enhance the network's ability to embed image features and speed up network training. The network proposed herein was trained using the real spiral geometry CT image data, namely the Low-dose CT Grand Challenge dataset. The results of the proposed networks were visually and quantitatively compared to that by other existing networks, including the image restoration iterative residual convolution network (IRLNet), residual coding-decoding convolutional neural network (REDCNN) and the FBP convolutional neural network (FBPConvNet)., Results: The results demonstrated that the proposed method was superior to other competing methods in terms of visual inspection and quantitative comparison., Conclusions: The MWResNet network is an effective method for suppressing noise and artifacts and maintaining edges details in the sparse-view CT images.

Objective: We propose a sparse-view helical CT iterative reconstruction algorithm based on projection of convex set tensor total generalized variation minimization (TTGV-POCS) to reduce the X-ray dose of helical CT scanning., Methods: The three-dimensional volume data of helical CT reconstruction was viewed as the third-order tensor. The tensor generalized total variation (TTGV) was used to describe the structural sparsity of the three-dimensional image. The POCS iterative reconstruction framework was adopted to achieve a robust result of sparse-view helical CT reconstruction. The TTGV-POCS algorithm fully used the structural sparsity of first-order and second-order derivation and the correlation between the slices of helical CT image data to effectively suppress artifacts and noise in the image of sparse-view reconstruction and better preserve image edge information., Results: The experimental results of XCAT phantom and patient scan data showed that the TTGVPOCS algorithm had better performance in reducing noise, removing artifacts and maintaining edges than the existing reconstruction algorithms. Comparison of the sparse-view reconstruction results of XCAT phantom data with 144 exposure views showed that the TTGV-POCS algorithm proposed herein increased the PSNR quantitative index by 9.17%-15.24% compared with the experimental comparison algorithm; the FSIM quantitative index was increased by 1.27%-9.30%., Conclusions: The TTGV-POCS algorithm can effectively improve the image quality of helical CT sparse-view reconstruction and reduce the radiation dose of helical CT examination to improve the clinical imaging diagnosis.

Objective: To establish a cone beam computed tomography (ECBCT) system for high-resolution imaging of the extremities., Methods: Based on three-dimensional X-Ray CT imaging and high-resolution flat plate detector technique, we constructed a physical model and a geometric model for ECBCT imaging, optimized the geometric calibration and image reconstruction methods, and established the scanner system. In the experiments, the pencil vase phantom, image quality (IQ) phantom and a swine feet were scanned using this imaging system to evaluate its effectiveness and stability., Results: On the reconstructed image of the pencil vase phantom, the edges were well preserved with geometric calibrated parameters and no aliasing artifacts were observed. The reconstructed images of the IQ phantom showed a uniform distribution of the CT number, and the noise power spectra were stable in multiple scanning under the same condition. The reconstructed images of the swine feet had clearly displayed the bones with a good resolution., Conclusions: The ECBCT system can be used for highresolution imaging of the extremities to provide important imaging information to assist in the diagnosis of bone diseases.

Objective: To investigate the methods for assessing angiogenesis in experimental liver fibrosis., Methods: Male C57BL/6 mice were randomly divided into a normal (unmodeled) group and a liver fibrosis model group.The model was established by a 4-week course of 10% CCl4 solution (in olive oil) intraperitoneal injection. Liver vasculature was observed by magnetic resonance (MR),computed tomography (CT),synchrotron radiation X-ray,and von Willibrand factor(vWF) immunofluorescence staining. Liver inflammation and fibrosis were observed by staining with hematoxylin-eosin and Sirius red.The t-test and Pearson's correlation analysis were used for statistical analyses., Results: Compared with the normal group,the model group had more robust inflammation and fibrosis in liver tissue.The liver tissue in the modeled mice showed significant deceases in MR signal intensity on T2WI before and after enhancement (386.67+/-69.04 vs.492.67+/-112.50,t =-2.456, P=0.026).The liver tissue in the modeled mice also showed significantly decreased enhancement CT values (P < 0.01).Synchrotron radiation X-ray imaging showed that the small vessels in the liver tissues of the modeled mice were significantly increased compared to that in the normal mice (P < 0.01).The MR T2W enhanced signal value (439.67+/-104.80, Pearson's r=0.714, P=0.009) and microvascular relative length (676.53+/-122.75, Pearson's r=0.791, P=0.002) were positive correlated with microvessel density (MVD) (14.50+/-5.95),as shown by detection of labeled vWF.The before and after CT enhancement difference (132.60+/-57.02, Pearson's r=-0.612, P=0.034) was negatively correlated with MVD., Conclusion: s MR,CT and synchrotron radiation X-ray imaging can be used for assessing angiogenesis in liver fibrosis,and the findings from each are correlated with the traditional MVD detection method. The two-dimensional imaging of synchrotron radiation X-ray is more intuitive,and has been confirmed as an effective evaluation method for liver angiogenesis.

Objective: To investigate the mechanism of salvianolic acid B (Sal B) action against liver fibrosis through preventing lipid peroxidation and regulating MMP-2 activity in liver., Method: The liver fibrotic model was induced through intraperitoneally injection of DMN at a dose of 10 microg x kg(-1) for every other day and lasting for 4 weeks. Sal B was administered (10 mg x kg(-1)), and perindopril (5 mg x kg(-1)) was used as positive control. Hepatic inflammation and collagen were observed with HE and sirius red staining. The liver function including serum ALT, AST activity, Alb and total bilirubin (T. Bil) level were determined. The hepatic lipid peroxidation including SOD and GST activities and GSH content were measured. Hepatic hydroxyproline (Hyp) content was detected with Jamall's method. The activity of metalloproteinase was assayed by gelatin zymography. The expressions of alpha-SMA, Col I in liver tissue were analyzed by Western blot., Result: The model rats had higher serum T. Bil content, ALT and AST activities but lower Alb content than the normal rats, also had remarkable inflammatory necrosis and collagen deposition in liver, with much higher Hyp content, protein expression of alpha-SMA and collagen I and MMP-2 activity in liver, but had a decreased GSH content, SOD and GST activities. Both Sal B and perindopril attenuated hepatic injury and collagen deposition in model rats, decreased serum ALT activity and hepatic Hyp content, down-regulated alpha-SMA and collagen I protein expressions and metalloproteinase-2 activity than those in the model group, but increased SOD activity and GSH content, and Sal B decreased serum T. Bil content and increased GST activity. Sal B had a much better comprehensive actions than perindopril., Conclusion: Sal B has a good preventive action against liver fibrosis, the action mechanism is related to the prevention from lipid peroxidation and down-regulation of metalloproteinase-2 activity in fibrotic liver.