Objective: To investigate the value of clinical data and qualitative and quantitative computed tomography (CT) in predicting the pathological grade of thymoma． Methods: The clinical data and CT images of 81 patients with confirmed pathological diagnoses of thymoma were retrospectively analyzed．The patients were divided into low-risk and high-risk groups according to the pathological results，and the clinical features and qualitative and quantitative CT findings were compared between the groups．The efficacy of different parameters in predicting the pathological thymoma grade was evaluated by logistic univariate and multivariate regression analyses and receiver operating characteristic (ROC) curves. Results: Sixty-two tumors were classified as low-risk thymoma and 19 as high-risk thymoma. The efficacies of both the maximum CT values on enhancement and maximum degree of enhancement for risk prediction were statistically significant (P＜0. 001)．Logistic regression analysis showed that both the maximum CT values on enhancement (OR = 0. 88，95% CI : 0. 83 － 0．94) and maximum degree of enhancement (OR = 0. 92，95% CI :0. 88－0. 97) were independent predictors of thymoma risk (P＜0. 001)．The area under the ROC curve (AUC) of the maximum CT values on enhancement was 0. 884，with a sensitivity of 68. 4% and a specificity of 96. 8% ; the AUC of the maximum degree of enhancement was 0. 833，with a sensitivity of 89. 5% and a specificity of 72. 6% . Conclusion Quantitative parameters based on enhanced CT are helpful for the preoperative prediction of thymoma risk stratification．The predictive efficacy of the maximum CT values on enhancement is superior to that of the maximum degree of enhancement.

Objective:To explore the imaging changes of lung lesions in patients with imported COVID-19 when reaching the discharge standard.Methods:The clinical and CT imaging data of 60 cured patients with imported COVID-19 and discharged from January to February 2020 in Anhui Province were retrospectively collected. At the initial diagnosis, 5 cases were mild, 53 were ordinary, and 2 were severe. The clinical characteristics of the patients and the characteristics of chest CT images at discharge were analyzed.Results:Fever (57 cases) and cough (55 cases) were the main symptoms in 60 patients. In 5 mild patients, 3 cases were negative in the whole course of CT examination, 2 cases were negative in the first time and abnormal in the second time. The first CT imaging features of 55 patients (53 common type and 2 severe type) were mainly bilateral lung involvement (51 cases), multiple lesions (33 cases), more common under the pleura (40 cases), and ground glass opacities were the most common (55 cases). The features of chest CT in clinical outcomes were that the ground glass shadow in the lung gradually faded and was completely absorbed (19 cases); the scope of ground glass shadow in the lung expanded and progressed to crazy-paving, consolidation shadow, and the lesion gradually absorbed again followed by fibrous cord shadows (27 cases); ground-glass opacities in the lungs quickly progressed to a consolidation and then slowly absorbed. Most of the lesions were accompanied by more residual fibrous cord shadows (4 cases). In 2 severe patients, the lesions in the lungs were larger ground glass, and a large amount of fibrous foci remained after slow absorption.Conclusions:Chest CT plays an important role in the diagnosis and treatment of imported COVID-19, and the degree of lung involvement seen on CT images is in good agreement with clinical outcome.

Objective: To explore the imaging changes of lung lesions in patients with imported COVID-19 patients when reaching the discharge standard. Method: The clinical and CT imaging data of 60 patients with imported COVID-19 cured and discharged from January to February 2020 in Anhui Province were retrospectively collected. The clinical characteristics of the patients and the characteristics of chest CT images at discharge were analyzed. Results: Fever (57 cases) and cough (55 cases) were the main symptoms in 60 patients. At the initial diagnosis, 5 cases were mild, 53 were ordinary, and 2 were severe. In 5 light patients, 3 cases were negative in the whole course of CT examination, 2 cases were negative in the first time and abnormal in the second time. . The first CT imaging features of 55 patients (53 common type and 2 severe type)were mainly bilateral lung involvement (51 cases), multiple lesions (33 cases), more common under the pleura (40 cases), and ground glass opacities were the most common. (55 cases). The clinical features of chest CT in clinical outcomes are that the ground glass shadow in the lung gradually fades and was completely absorbed (19 cases); the scope of ground glass shadow in the lung expanded and progressed to crazy-paving, consolidation shadow, and the lesion gradually absorbs again followed by Fibrous cord shadows (27 cases); ground-glass opacities in the lungs quickly progressed to a consolidation and then slowly absorbed . Most of the lesions were accompanied by more residual fibrous cord shadows (4 cases). In 2 severe patients, the lesions in the lungs were larger ground glass, and a big amount of fibrous foci remained after slowly absorption. Conclusion Chest CT plays an important role in the diagnosis and treatment of imported COVID-19, and the degree of lung involvement seen on CT images is in good agreement with clinical outcome.

Objective To investigate the effect of muscle function on structural stress in patient with lumbar disc herniation (LDH), by observing the stress changes in LDH lumbar-pelvis finite element model loaded with muscle force. Methods One normal healthy volunteer and one LDH patient were selected. Their CT data were collected to establish two corresponding normal and LDH lumbar-pelvis finite element models, and their gait data were also simultaneously collected to drive the AnyBody musculoskeletal model. The muscle force around the lumbar and pelvis as well as the hip-joint force were obtained as the loading condition. Self-loading of the normal and LDH model as well as the normal model loaded with LDH muscle forces were conducted seperately. Then the stress changes in L4 and L5 intervertebral discs and sacroiliac joints under two above loading conditions were compared. Results The stress curve of normal model loaded with LDH muscle force showed a unimodal stress curve, instead of a bimodal curve, and such trend of stress-time curve was as same as the trend of the LDH model during self-loading. But the stress difference in L4 and L5 intervertebral discs and sacroiliac joint of the normal model loaded with LDH muscle force was smaller than that in the LDH model during self-loading. Conclusions Abnormal muscle function of LDH could lead to abnormal joint stress of the intervertebral discs and sacroiliac joint. Structural imbalance itself could lead to stress imbalance, and muscle as a driving factor was an important cause of anomaly structural dynamic stress, thus leading to abnormal joint motion patterns. Therefore, attention should be paid to assessment of the imbalance of peripheral muscle function in clinical treatment of LDH.

Objective To compare the MRI features of ovarian thecoma-fibroma and adult-type ovarian granulosa cell tumor (OGCT),and to investigate the differential value of MRI.Methods 13 patients (8 cases of ovarian thecoma-fibroma,5 cases of adult-type OGCT)confirmed by pathology were collected,in which MRI findings were analyzed retrospectively.Results 13 lesions were all unilateral.The shape of more lesions appeared round or oval,and huge lesions were lobulated.Most tumors were dominant solid and well-defined borders.The length-diameter of ovarian thecoma-fibromas ranged from 23 to 268 mm,with the mean diameter of (124±84)mm;on T1WI the solid part of tumors showed equal signal in 5 cases,slight lower signal in 3 cases,on T2WI all tumors were heterogeneous signal,6 lesions appeared equal signal with obscure nebulous high signal;all of 8 lesions were enhanced slightly;4 cases were accompanied with pelvic effusion and other type tumors of the ovarian.The length-diameter of adult-type OGCT tumors ranged from 27 to 110 mm, with the mean diameter of (84±33)mm;the solid part of lesions showed slight lower signal on T1WI and high signal on T2WI,the honeycomb and fissure cystic areas were found in all tumors,4 cases were accompanied with hemorrhage;all tumors were enhanced from moderately to highly,and delay contrast enhancement;the cases were accompanied with endometrial hyperplasia in 3 cases,endometrial carcinoma in 1 case.The non-enhanced cystic areas of two groups of tumors showed lower signal on T1WI and high signal on T2WI. Conclusion There are different characteristics between ovarian thecoma-fibroma and adult-type OGCT on MRI findings,which are helpful to the differential diagnosis.

Objective To evaluate the MDCT and MRI findings of the ovarian thecofibroma.Methods 15 patients with 16 lesions of ovarian thecofibroma confirmed by pathology after surgery were analyzed retrospectively.MDCT was performed in 1 2 patients and MRI in 8.Results 16 lesions were all unilateral,of which 1 patient had 2 lesions on the same side.10 lesions were located in the right side of ovary,while 6 ones were in the left side.The shape of more lesions was round or oval,and that of huge lesions was lobulated. 14 lesions were well-defined.These tumors were solid in 4 lesions,mixed in 9,and cystic in 3.The largest diameter of tumors ranged from 20 to 220 mm with a mean value of (89±58.29)mm.Plain MDCT showed the substantial part of tumors with iso-den-sity or slight lower density with the mean CT value of (40±8)HU.There was no or slight enhancement in comparison with the mean CT values of (49±9)HU on enhanced MDCT.5 lesions with isointensity and 3 with slight hypointensity on T1-weighted ima-ges,and all the tumors with heterogeneous signal on T2-weighted images were found.6 lesions appeared isointensity with obscure nebulous high signal on T2-weighted.The capsules of 5 lesions showed incomplete ring with lower signal.There was high signal ring outside of tumor capsule on T2-weighted in 5 lesions.All of 8 lesions were enhanced slightly,and the cystic portion was lower signal on T1-weighted images and high signal on T2-weighted images.Among all patients,ascites was found in 10 cases (66.7%)and other kinds of tumors of ovarian or uterus in 13 cases (86.7%).Conclusion MDCT and MRI findings of the ovarian thecofibroma have cer-tain characteristics,which is helpful for the diagnosis and differential diagnosis.

Objective To discuss the influence of the change in ceiling-mounted shield positions on the radiation doses to the first and second operators during percutaneous coronary intervention.Methods In this study,the entrance surface dose (ESD) rates were measured for the first and second operators at 125 cm and 155 cm height on different ceiling-mounted shield positions separately through transradial approach.Measurements were repeated 20 times for each position and T test was used for statistical analysis of dose rate arithmetic mean values.Results For the first operator,the effective dose values were obtained only on left foot position.The ESD rate values at ceiling-mounted shield position close to patient were higher than that close to operators (t125 =46.9,t155 =4.1,P ＜0.05).For the second operator,the ESD rate values on his foot position,right foot position,left anterior oblique position and right anterior oblique position at ceiling-mounted shield position close to the operator,were higher than that close to the patient separately (t125 =11.9,24.4,11.2,2.7,t155 =16.1,2.8,14.4,28.8,P ＜ 0.05).The ESD rate values on head position,left foot position,left head position at ceiling-mounted shield position close to the operator,were lower than that close to the patient (t125 =-4.3,-2.4,-80.4,t155 =-10.2,-6.7,-152.6,P ＜ 0.05).Conclusions The change in the ceiling-mounted shield positions gave rise to change in radiation dose to the operators.The changes in radiation doses caused by the changes in ceiling-mounted shield positions are different in various angiographic positions.Ceiling-mounted shield should be used in a reasonable way in agreement with different positions in percutaneous coronary intervention so as to effectively reduce operators radiation dose.

Objective To investigate the effects of mitochondrial DNA (mtDNA) copy number in peripheral blood and related factors on the risk of hypertension in coal miners.Methods A case-control study was conducted in 378 coal miners with hypertension and 325 healthy coal miners recruited from Datong Coal Mine Group.A standard questionnaire was used to collect their general information,such as demographic characteristics,habits and occupational history.Fluorescence quantitative PCR was performed to detect the copy number of mtDNA.Logistic regression model was applied for identifying the related risk factors of hypertension and analyzing the interaction between mtDNA copy number and risk factors.Results The prevalence of hypertension of high mtDNA copy number was lower than mtDNA copy numberin 0-5.67 group,but the difference was not statistically significant (P=0.414).Alcohol drinking (OR=1.80,95％CI:1.26-2.56),family history of hypertension (OR=1.74,95％ CI:1.20-2.50),work shifts (OR=0.69,95％ CI:0.48-0.99),education level (P=0.012) and family monthly income level (P=0.001) were related to the prevalence of hypertension.There were potential interactions between mtDNA copy number and alcohol drinking,family monthly income level,family history of hypertension,respectively.Alcohol drinking was a risk factor for hypertension [1.77(1.25-2.50)].Potential interactions between mtDNA copy number and alcohol drinking reduced the risk of hypertension (OR=1.20,95％CI:1.07-1.35).Family history of hypertension was a risk factor for hypertension [1.81(1.26-2.59)].Potential interactions between mtDNA copy number and family history of hypertension reduced the risk of hypertension (OR=1.24,95％ CI:1.09-1.41).Family monthly income level was a protect factor for hypertension [0.55(0.46-0.66)].Potential interactions between mtDNA copy number and family monthly income level increased the protection role of hypertension (OR=0.90,95％CI:0.86-0.94).Conclusion mtDNA copy number variation was not significantly associated with the prevalence of hypertension in coal miners,but mtDNA copy number shewed multiplication interaction on the prevalence of hypertension with alcohol drinking,family monthly income level as well as family history of hypertension and made their influences weaken.

Gardner syndrome is a rare disease in oral and maxillofacial diseases which is characterized by intestinal polyposis, multiple osteomas, skin and soft tissue tumors. Early treatment has a better prognosis; therefore the early diagnosis of Gardner syndrome is very important. Maxillofacial pathology always appears to precede the other pathologies, so the importance of early detection of the syndrome by dentists is also emphasized. This review summarizes the etiology of Gardner syndrome-related mutations and the clinical manifestations of Gardner syndrome characterized by oral and maxillofacial deformities, multiple gastrointestinal polyps, and desmoid tumour, and their associated treatment.

Objective To discuss the effect of the bedside shielding protection on the first and second operators against position radiation in percutaneous coronary intervention.Methods The surface entrance dosage rate for the first and second operators at 125 cm height with and without radiation protection shielding (provided separately) were measured.The t-test was used for statistical analysis of arithmetic mean values of dosage rates.And the effect of bedside shielding protection was calculated.Results The position radiation dosage rate at which the first operator exposed was significantly higher than that for the second in the case of no bedside protection (t =97.1-2 263.0,P ＜ 0.05),whereas the dosage rate at which the first operator (except for the left foot position) exposed was significantly lower than that for the second in the case of no bedside protection (t =-80.9-275.1,P ＜ 0.05).The shielding effect of bedside protection on the first and second operators was in the range of 92.26％-99.36％ and 27.83％-97.90％,respectively.Conclusions The bedside protection may effectively reduce position radiation dose to patients and the use of bedside protection changed the trends in the dose distribution in operators' standing region.Attention should be focused on the radiation protection of the second operators in daily work by making full use of bedside protection.