Objective To explore the CT features of pediatric pleuropulmonary blastoma(PPB)and its clinical application value.Methods The CT features of 9 patients with PPB confirmed by postoperative pathology were analyzed retrospectively and compared with the postoperative pathological types.Results There was 1 case with type Ⅰ PPB,whose CT manifestations were multilocular septated cystic space-occupying lesions,with mild enhancement of the cyst wall and septum after enhancement,and was misdiagnosed as type Ⅳ congenital pulmonary airway malformation(CPAM)before surgery.There were 2 cases with type Ⅱ PPB,whose CT manifestations were well-defined cystic and solid space-occupying lesions,closely related to the pleura,with uneven mild to moderate progressive enhancement of the solid components,and multiple thickened and tortuous blood vessels were visible in both lesions.The preoperative imaging diagnosis and pathological type prediction of type Ⅱ PPB,lesions were completely consistent with the post-operative pathological diagnosis and type,with a diagnostic accuracy of 100％.There were 6 cases with type Ⅲ PPB,whose CT man-ifestations were solid soft tissue density space-occupying lesions,with uneven enhancement of the solid part after enhancement,and multiple thickened and tortuous blood vessels within the masses.Before surgery,2 cases(33.3％)with type Ⅲ PPB were misdiag-nosed as Askin tumors of the chest wall,and the diagnostic accuracy was 66.7％.Conclusion PPB is a rare tumor in the chest of children,with high malignancy.Type Ⅰ PPB is difficult to be differentiated from benign cystic lesions of the chest before surgery.For suspected type Ⅰ PPB pulmonary cystic lesions,the postoperative pathological sampling should be extensive to search for whether there are primitive mesenchymal cells for a clear diagnosis.The CT features of type Ⅱ and Ⅲ PPB are cystic-solid and solid masses in the chest,with clear boundaries,pseudocapsules,and nodular enhancement.Generally,the consistency rate between preoperative imaging diagnosis and pathological type prediction and postoperative pathological diagnosis and type is relatively high.Combining the CT characteristics of PPB is helpful to improve the accuracy of preoperative diagnosis and pathological type prediction,and can assist clinicians in selecting reasonable treatment plans.

Objective To explore the clinical characteristics and CT features of malignant ovarian germ cell tumor(MOGCT)in children.Methods The CT image features and clinical characteristics of 27 cases of MOGCT confirmed by postoperative pathology were retrospectively analyzed.Results There were 6 cases of dysgerminoma(DG)(22.2%).The CT features were solid soft tissue masses with mild to moderate enhancement,"separate-like"enhancement within the mass,and thickened blood vessels around it.There were 8 cases of immature teratoma(IT)(29.7%).The CT features were mixed-density masses with soft tissue,fat,and calcifi-cation inside,and the solid part was significantly enhanced.There were 7 cases of yolk sac tumor(YST)(25.9%).The CT features were significantly enhanced,tortuous small blood vessels inside the mass,presenting a"bright spot sign".There were 3 cases of non-gestational choriocarcinoma(11.1%).The CT features were a low-density mass with large central necrosis,obvious enhance-ment after contrast,and thickened ovarian arteries and veins around it.There were 3 cases of mixed germ cell tumor(MGCT)(11.1%).The CT features were related to the tumor components.Conclusion MOGCT in children have their own CT characteristics.Combi-ning with the clinical manifestations of the children and serum tumor markers,qualitative diagnosis of the lesions can be made,which provides reliable help for the formulation of clinical diagnosis and treatment plans.

Objective To explore the clinical characteristics and CT features of malignant ovarian germ cell tumor(MOGCT)in children.Methods The CT image features and clinical characteristics of 27 cases of MOGCT confirmed by postoperative pathology were retrospectively analyzed.Results There were 6 cases of dysgerminoma(DG)(22.2%).The CT features were solid soft tissue masses with mild to moderate enhancement,"separate-like"enhancement within the mass,and thickened blood vessels around it.There were 8 cases of immature teratoma(IT)(29.7%).The CT features were mixed-density masses with soft tissue,fat,and calcifi-cation inside,and the solid part was significantly enhanced.There were 7 cases of yolk sac tumor(YST)(25.9%).The CT features were significantly enhanced,tortuous small blood vessels inside the mass,presenting a"bright spot sign".There were 3 cases of non-gestational choriocarcinoma(11.1%).The CT features were a low-density mass with large central necrosis,obvious enhance-ment after contrast,and thickened ovarian arteries and veins around it.There were 3 cases of mixed germ cell tumor(MGCT)(11.1%).The CT features were related to the tumor components.Conclusion MOGCT in children have their own CT characteristics.Combi-ning with the clinical manifestations of the children and serum tumor markers,qualitative diagnosis of the lesions can be made,which provides reliable help for the formulation of clinical diagnosis and treatment plans.

Objective To explore the CT features of pediatric pleuropulmonary blastoma(PPB)and its clinical application value.Methods The CT features of 9 patients with PPB confirmed by postoperative pathology were analyzed retrospectively and compared with the postoperative pathological types.Results There was 1 case with type Ⅰ PPB,whose CT manifestations were multilocular septated cystic space-occupying lesions,with mild enhancement of the cyst wall and septum after enhancement,and was misdiagnosed as type Ⅳ congenital pulmonary airway malformation(CPAM)before surgery.There were 2 cases with type Ⅱ PPB,whose CT manifestations were well-defined cystic and solid space-occupying lesions,closely related to the pleura,with uneven mild to moderate progressive enhancement of the solid components,and multiple thickened and tortuous blood vessels were visible in both lesions.The preoperative imaging diagnosis and pathological type prediction of type Ⅱ PPB,lesions were completely consistent with the post-operative pathological diagnosis and type,with a diagnostic accuracy of 100％.There were 6 cases with type Ⅲ PPB,whose CT man-ifestations were solid soft tissue density space-occupying lesions,with uneven enhancement of the solid part after enhancement,and multiple thickened and tortuous blood vessels within the masses.Before surgery,2 cases(33.3％)with type Ⅲ PPB were misdiag-nosed as Askin tumors of the chest wall,and the diagnostic accuracy was 66.7％.Conclusion PPB is a rare tumor in the chest of children,with high malignancy.Type Ⅰ PPB is difficult to be differentiated from benign cystic lesions of the chest before surgery.For suspected type Ⅰ PPB pulmonary cystic lesions,the postoperative pathological sampling should be extensive to search for whether there are primitive mesenchymal cells for a clear diagnosis.The CT features of type Ⅱ and Ⅲ PPB are cystic-solid and solid masses in the chest,with clear boundaries,pseudocapsules,and nodular enhancement.Generally,the consistency rate between preoperative imaging diagnosis and pathological type prediction and postoperative pathological diagnosis and type is relatively high.Combining the CT characteristics of PPB is helpful to improve the accuracy of preoperative diagnosis and pathological type prediction,and can assist clinicians in selecting reasonable treatment plans.

Objective To investigate the clinical and imaging features of extralobar pulmonary sequestration(ELS)with torsion.Methods The clinical and imaging data,surgical records and pathological results of four ELS children with torsion were analyzed ret-rospectively.Results All four children presented with abdominal pain,and all CT scans showed soft tissue masses on the medial side of the lower lobe,and there were 2 masses with long fusculine-shaped in the right pleural cavity,2 round masses in the left pleural cavity,all of which were accompanied by pleural effusion and poor ventilation of adjacent lung lobes.There were 1 case without enhance-ment,1 case with mild enhancement,and 2 cases with simple marginal linear enhancement.There were no patients with definitive supplying artery and 3 cases with peripheral post-intercostal dilated veins.Intraoperative ELS combined with torsion was shown,and the nutrient artery were derived from the thoracic aorta.All ELS showed bleeding and necrosis according to the pathological results,and 1 case was complicated with congenital pulmonary airway malformation(type 2).Conclusion ELS combined with torsion is mostly abdominal pain as the first symptom,and there are soft tissue mass adjacent to the lower lobe with pleural effusion on the affected side as the imaging features with no,mild or marginal linear enhancement,with no supplying artery,and with intracostal posterior venous expansion.

Objective:To explore the positive rates of 2019-nCoV nucleic acid at different time of courses of COVID-19.Methods:Patients with confirmed COVID-19 were enrolled in this study. Nasal and throat swabs were collected from different courses of disease. Real-time RT-PCR was used to detect 2019-nCoV nucleic acid.Results:From January 23 to February 20, 2020, a total of 120 confirmed cases of COVID-19 were reported in Xi’an, and 85 cases(70.83%) were positive in first detection. The COVID-19 cases included consistently nucleic acid positive and intermittently nucleic acid positive patients. 2019-nCoV nucleic acid could be detected in incubation period, and the longest observed duration of nucleic acid positive in this study was 26 days. The positive rate of 2019-nCoV nucleic acid was up to 84.21% on the 6th day, and the positive rate decreased as time passed during the course of COVID-19. Three patients (2.86%) were tested positive for 2019-nCoV nucleic acid again in nasal and throat swabs after discharge.Conclusions:The positive rate of 2019-nCoV nucleic acid was higher in the early stage of disease. 2019-nCoV nucleic acid can be detected in incubation period, and virus shedding may last for a long period.

Objective To understand the distribution of novel coronaviruses in the external environment of confirmed COVID-19 cases. Methods Environmental surface swab specimens such as bed rails, doorknob, closestool, hand washing sink, table, locker,ward pager, mobile phone, cup, clothes, were collected from the sentinel hospital of COVID-19, and samples were collected for the nucleic acid detection by RT-PCR. Results A total of 150 environmental samples were collected from 30 confirmed COVID-19 cases, 6 samples were determined to be novel coronaviruses postive (positive rate 4.00%). The total 14 mobile phone showed 3 novel coronaviruses positive.Among the 30 confirmed COVID-19 cases, 6 cases (positive rate 20.00%)were found novel coronaviruses in the external environment. Conclusions Novel coronaviruses exists in external environment of confirmed COVID-19 cases, which indicates the potential risk of COVID-19 infection.

Objective:To explore the efficacy and prognostic factors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of relapsed/refractory acute myeloid leukemia (AML).Methods:The clinical data of 35 patients with relapsed/refractory AML treated with allo-HSCT in the Affiliated Cancer Hospital of Zhengzhou University from June 2011 to October 2018 was retrospectively analyzed. The overall survival (OS), disease-free survival (DFS), graft versus host disease (GVHD) incidence, transplantation related mortality and recurrence rate were calculated, and the risk factors affecting prognosis were analyzed.Results:Hematopoietic reconstitution was obtained in all patients after transplantation. The 100 d incidence of grade Ⅱ-Ⅳ acute GVHD was (22.9±7.7)%, and the 3-year incidence of chronic GVHD was (49.5±10.60)%. The median follow-up time after transplantation was 14.1 months (4.2-89.4 months). In all cases, 18 cases survived (including 16 cases of DFS), and 17 cases died. Fourteen cases relapsed, and the median recurrence time was 4.7 months (2.9-32.4 months). The 3-year OS rate and DFS rate were (44.4±9.3)% and (43.0±9.5)%, respectively. Univariate analysis showed that the non-remission disease before transplantation, poor genetic risk grade before transplantation and recurrence after transplantation were the risk factors for OS (all P < 0.05). The 3-year OS rates in complete remission before transplantation group and non-remission before transplantation group were (63.2±12.0)% and (15.7±12.8)% ( P = 0.025), the 3-year DFS rates were (62.2±12.3)% and (15.3±12.7)% ( P = 0.028), and the 3-year recurrence rates were (28.2±10.7)% and (80.6±15.7)% ( P = 0.057). The 3-year recurrence rate in genetic high-risk group was higher than that in middle-risk group and low-risk group [100.0%, (45.0±12.1)% and (14.3±13.2)%, P = 0.045]. The 3-year tansplantation related mortality was (18.7±7.7)%. Conclusions:Allo-HSCT is an effective method for salvage treatment of relapsed/refractory AML, and recurrence is the main factor affecting survival. Reducing tumor load before transplantation is very important for reducing recurrence and improving curative effect.

The efficacy and safety of co-transplantation of unrelated donor peripheral blood stem cells (UD-PBSCs) combined with umbilical cord mesenchymal stem cells (UC-MSCs) in refractory severe aplastic anemia-Ⅱ(RSAA-Ⅱ) were analyzed retrospectively. Fifteen patients with RSAA-Ⅱ underwent UD-PBSCs and UC-MSCs co-transplantation, among whom 14 cases had hematopoietic reconstitution without severe graft versus-host disease (GVHD). The 5-year overall survival rate was 78.57%. Combination of UD-PBSCs and UC-MSCs transplantation could be a safe and effective option for RSAA-Ⅱ.

Objective: To investigate the safety and efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) containing cladribine sequential busulfan regimen for refractory/relapsed acute myeloid leukemia (AML) . Methods: The clinical data of 12 refractory/relapsed AML patients received allo-HSCT with cladribine sequential busulfan regimen. Results: ① Of the 12 patients, 9 were males and 3 females, with a median age of 36 (27-50) years. The donors were identical sibling (3) , matched unrelated (1) and haploidentical family member (9) respectively. Nine patients reached partial remission and other remained no remission after chemotherapy before allo-HSCT. The median previous chemotherapy courses before allo-HSCT were 6 (2-13) . ② Conditioning regimen: Smostine 250 mg·m^-2·d^-1, d-7; Cladribine 5 mg·m^-2·d^-1, d-6 to d-2; Cytarabine Arabinoside 2 g·m^-2·d^-1, d-6 to d-2; Busulfan 3.2 mg·m^-2·d^-1, d-6 to d-3; Rabbit anti-human thymocyte immunoglobulin (ATG) 1.5 mg·m^-2·d^-1 (unrelated donor transplantation) or 2.0-2.5 mg·m^-2·d^-1 (haplo-HSCT) , d-4 to d-1. ③ Of the 12 patients, 11 patients attained complete haploidentical engraftment, one case occurred primary graft failure. The median durations for neutrophils and platelet implantations were 15 (15-21) and 19 (17-30) days respectively. ④After conditioning, no hepatic veno-occlusive diseases were observed, hemorrhagic cystitis occurred in 2 patients, 8 patients had fever, 3 cases experienced acute GVHD grade II, localized chronic GVHD occurred in 8 patients. ⑤The median follow-up was 8 (4-12) months. Leukemia relapse occurred in 2 patients at time of 6, 12 months after allo-HSCT. The estimated 1-year OS and DFS were (71.1±1.8) % and (62.2±1.8) %, respectively. Conclusions allo-HSCT with cladribine sequential busulfan regimen was a feasible choice with favorable outcome for refractory/relapsed AML.