Objective To explore the effects of different body positions at the expiratory phase thinsection multi-slice spiral CT on the diagnosis of pulmonary air trapping after allogeneic hematopoietic stem cell transplantation(allo-HSCT).Methods Thirty-one allo-HSCT patients underwent the expiratory phase low-dose MSCT lung scanning at supine and prone positions to detect whether they have air trapping lesion,the volume percent of air trapping region (CT value ≤-700 HU at expiratory phase) against the whole lung was measured by using GE workstation after grading.Statistical analysis on lesion detection rate was performed with McNemar test and volume percent with rank sum test.Results Air trapping regions were observed in 8 patients (25.8％,8/31) who performed CT scan at the supine position,while 15 cases (48.4％,15/31)were positive for prone position CT scan.Seven cases showed positive results at both body positions.Statistical significance in the positive detection rate at supine and prone positions was found (x2 =4.00,P =0.039).The volume fraction of the two positions was 13 for supine position and 21 for prone position with statistical significance (Z =-3.37,P =0.001).Sensitivity at prone position CT scan to detect air trapping was much higher than that at supine position CT scan.Conclusion For allo-HSCT patients with chronic rejection reaction,performing expiratory phase thin-section CT scan and prone position scan can not only improve the detection rate of lung forepart lesions,but also preliminarily evaluate the severity of the air trapping,which can provide a basis for the early diagnosis and treatment in clinics.

Objective:To explore the application value of overall nursing intervention in PET/MR imaging in children with epilepsy.Methods:A total of 48 pediatric epilepsy patients who underwent PET/MR imaging in the Nuclear Medicine Department of the First Medical Center of the PLA General Hospital from July 2018 to October 2019 were enrolled. Among them, 24 patients with overall nursing intervention were used as the experimental group, and 24 patients were routine nursing intervention patients, who were served as the normal control group, and the examination time, Self-Rating Anxiety Scale (SAS) scores and patient satisfaction scores (filled in by the patient′s guardian) of the experimental group and the control group were collected and compared.Results:The inspection time of the experimental group was (15.1±0.5) min, significantly lower than (24.8±1.3) min of the control group ( tvalue was 32.940, P<0.01); the SAS score of the experimental group was (35.7±4.2) points, lower than(43.8±3.3) points of the control group ( tvalue was 7.357, P<0.01), and the patient satisfaction score was (92.8±5.5) points, higher than (69.8±11.1) points of the control group ( tvalue was 9.088, P<0.01 or 0.05). Conclusion:Overall nursing intervention in PET/MR imaging of pediatric patients with epilepsy can significantly cut down the examination time, reduce the anxiety of patients′ family members and improve the satisfaction of nursing care. It lays the foundation for clinicians to further accurately diagnose epilepsy foci and has important application value.

Objective To evaluate the diagnostic efficiency of the parameters obtained from PET/MR in brain tumors.Methods In this prospective study,28 patients (21 males,7 females,age range: 6-82 years) with clinical suspicion of brain tumor from November 2012 to September 2015 underwent PET/MR multi-modality imaging.The examination of PET/MR included 11C-MET PET and multiple MR sequences.The qualities of images were estimated firstly.The ROC curve and the accuracy of SUVmax,ADCmean,rCBF and NAA/(Cho+Cre) ratio were calculated.The pathology or final clinical diagnosis was taken as the standard.The diagnostic efficiency of the multi-modality imaging was determined based on the cutoff values of the four parameters.Two-sample t test was used to analyze the differences of parameters between glioma group and inflammatory group.Results SUVmax,ADCmean,rCBF and NAA/(Cho+Cre) ratio were validated to be effective parameters in diagnosing brain tumors with the diagnostic accuracy of 89.3％(25/28),82.1％(23/28),78.6％(22/28) and 75.0％(21/28),respectively.The SUVmax exhibited the highest diagnostic accuracy,while the diagnostic efficiency of the combination of four parameters was superior to the separate parameter.The values of SUVmax,rCBF and NAA/(Cho+Cre) ratio were significantly different between glioma group(n=10) and inflammatory group(n=11;t values:-2.31,-3.11,-2.77,all P<0.05).Conclusions PET/MR can provide a one-stop examination with multi-modality imaging of brain.The obtained parameters SUVmax,ADCmean,rCBF and NAA/(Cho+Cre) ratio,especially their combination,have effective diagnostic values on brain tumor.

Objective:To investigate the value of multiple parameters and the combined model based on 18F-fluorodeoxyglucose (FDG) PET/MR in the differential diagnosis of benign and malignant pancreatic tumors. Methods:A total of 76 patients (50 males, 26 females, age (45.2±18.0) years) with clinically suspected pancreatic tumor who underwent PET/MR between December 2012 and September 2020 in First Medical Center of Chinese PLA General Hospital were retrospectively selected. All patients had definitive diagnoses. PET/MR sequences included T 1 weighted imaging (WI; convention and contrast enhancement), T 2WI, diffusion weighted imaging (DWI) and 18F-FDG PET sequences. Morphological characteristics and scores of lesions in MRI were evaluated. Parameters including parameters of PET and DWI, as well as parameters derived from histogram analysis of apparent diffusion coefficient (ADC) and standardized uptake value (SUV) (maximum (max), minimum (min), mean, median, standard deviation (SD), skewness, kurtosis, entropy) were measured. Independent-sample t test or Mann-Whitney U test were used for data analysis. PET/MR combined model was measured based on logistic regression analysis. Receiver operating characteristic (ROC) curve analysis was used to calculate the differential diagnosis efficacy of PET/MR multiparameters and combined model for benign and malignant lesions. Results:Among 76 patients, 55 were malignant and 21 were benign. (1) Visual evaluation. The main manifestations of pancreatic cancer were unclear margin, abnormal internal MR signal and enhancement, decreased ADC signal and increased radioactive uptake. The main manifestations of benign tumor lesions of pancreas were clear margin, even signal and enhancement, no reduction of ADC, decreased radioactive uptake. (2) Diagnostic efficacy. Multiparameter model established based on logistic regression analysis included SUV max, SUV SD, ADC entropy and ADC skewness. The efficiency of differential diagnosis for benign and malignant pancreatic tumors were shown as follows: multiparametric diagnostic model>ADC entropy>MR score>SUV max>SUV SD>ADC skewness. The multiparametric diagnostic model had the best diagnosis efficiency with the area under curve (AUC) of 0.86, the sensitivity of 69.1%(38/55), and the specificity of 100%(21/21) ( z=-8.73, P<0.001). Conclusions:MR score and multiple quantitative parameters obtained from 18F-FDG PET/MR can be used to differentiate benign and malignant pancreatic tumors. Compared with independent parameter of PET/MR, multiparametric model can further improve the diagnostic efficiency.

Objective To explore the value of 11C-methionine(MET)PET/CT radiomics model for evaluating isocitrate dehydrogenase1(IDH1)status of glioblastoma.Methods Data of 157 patients with glioblastoma who underwent 11C-MET PET/CT examination,including 68 cases of IDH1 mutation and 89 cases of IDH1 wild-type were retrospectively analyzed.The patients were divided into training set(n=125)and validation set(n=32)at the ratio of 8:2.Based on PET/CT images,lesions ROI were delineated and radiomics features were extracted and screened to establish radiomics models with logistic regression(LR),support vector machine(SVM)and decision trees(DT),respectively.Meanwhile,the nomogram based on patients'age and radiomics features was drawn.The efficacy of radiomics models and clinical-radiomics nomogram for evaluating IDH1 status were comparatively observed.Results The area under the curve(AUC)of DT radiomics model for evaluating IDH1 status of glioblastoma in training set was 0.910,higher than that of LR(0.697)and SVM(0.698)models(both P＜0.05).In validation set,the AUC of DT model for evaluating IDH1 status of glioblastoma was 0.805,which was higher than that of LR model(0.740)and clinical-radiomics nomogram(0.704)(both P＜0.05).Conclusion 11C-MET PET/CT radiomics model based on DT was helpful for evaluating IDH1 status of glioblastoma.