Purpose To investigate the influence of the region of interest (ROI) selection on the repeatability of 64 slice spiral CT perfusion parameters for the peripheral lung cancer.Materials and Methods The 64 slice spiral CT perfusion images of thirty-seven patients with peripheral lung cancer were retrospectively analyzed.The perfusion parameters including blood flow (BF),blood volume (BV),Patlak blood volume (PBV),permeability surface area product (PS),and mean transit time (MTT) were obtained by using three ROI selection methods including maximum area of ROI (ROIm),round of ROI (ROIr),and volume of ROI (ROLv),and these parameters were measured by two observers repeatedly.The repeatability and reliability of the values of these perfusion parameters by using different ROI methods or measured by different observer were determined.Results The perfusion parameters derived from three ROIs all had a excellent intraobserver and interobserver agreement (ICC＞0.75).Besides,the values of the perfusion parameters by using different ROI methods had no significant difference (P＞0.05),but the data obtained by ROIm and ROIv were more stable than that obtained by ROIr.Conclusion The repeatability of the perfusion parameters obtained from above three ROIs is excellent,but ROIm and ROIv may be more suitable than ROIr to assess vascular perfusion of peripheral lung cancer.

Objective To evaluate the relationship between myocardial perfusion imaging quality and reconstruction time of dual-souce CT (DSCT).Methods Myocardial perfusion imaging was performed in 28 subjects using second-generation DSCT.The coronary arteries of all selected subjects were normal.280 ms temporal resolution was used,and the image of 30 ％-80 ％ R-R phase was reconstructed by retrospective ECG gating interval 5 ％.The artifact area of myocardial perfusion iodine map image of each R-R interval were obtained.Average segment artifacts of the heart bottom,central,apical,apical level of heart level were calculated and statistical analyzed.Results The artifact area of myocardial perfusion iodine map of the heart bottom,central,apical,and the whole heart had statistically significant differences (all P＜0.01),and the minimum artifact area was in60％ R-R phase ([0.31±±0.28]cm2,[0.18±0.23]cm2,[0.13±0.13]cm2,[0.22± 0.18]cm2).There was no difference between different phases of the heart apical level (P=0.634).The minimum artifact area of myocardial perfusion iodine map of the heart bottom,central,apical,apical level in 60％ R-R phase at the heart apical,the difference had statistically significant (F 3.701,P=0.014),there was no difference between the heart apical and central (P＞0.05),but the difference between the heart apical and other parts had statistically significant (P＜0.05).Conclusion Using 280 ms temporal resolution,second-generation DSCT can achieve the optimal myocardial perfusion imaging quality using 60％ R-R phase reconstruction.

Objective To investigate the diagnostic value of dual-energy CT virtual non-contrast (VNC) technology for osteoporosis(OP). Methods Dual-energy CT images of 50 patients with lumbar traumas were collected prospectively.Patients who suffer from vertebral bodies fractures between lumbar 1 to 4, have internal metal fixations or underwent percutaneous vertebroplasty, or presented tumors or compromised bone metabolism induced by diseases or medications were excluded.The scanning range was from the upper edge of the 12th thoracic vertebral body to the lower edge of the first sacral vertebral body. The voltages of tubes A and B were 90 kV and Sn 150 kV,and the reference tubes currents were 220 mAs and 138 mAs. Image reconstruction was performed using Advanced Modeled Iterative Reconstruction (ADMIRE)with iterative strength of 3 and convolution kernel of Qr 40.The default parameters of the virtual non-contrast software were corrected by the standard recommended by the Bone Marrow software of the post-processing platform Syngo.via,and the CT value of calcium(contrast media CM),the CT value of mixed energy images(regular CT value,rCT),the calcium density(CaD)and the fat fraction(Fat)were measured. The bone mineral density (BMD) and T score of each lumbar vertebra from lumbar 1 to lumbar 4 were measured by dual energy X-ray absorptiometry(DXA).With T score less than or equal to the 2.5 standard deviation as the gold standard for the diagnosis of OP,correlations between CT measurements and vertebral BMDs were analyzed using Pearson correlation analysis and linear regression and the diagnostic values of different CT measurements for OP were compared using receiver operating characteristic curve. Results Each of the vertebral bodies was analyzed as a single unit.Fifty of them were osteoporotic and the rest 116 were non-osteoporotic.Except for Fat,the CT measurement parameters of the osteoporotic vertebral bodies were lower than those of the ones without osteoporosis, and the difference was statistically significant (P<0.01).CM,rCT and CaD were significantly correlated with BMD(r were 0.75,0.65,0.71,all P<0.01)and there was a linear relationship(F were 209.91,120.24,167.69,all P<0.01).Meanwhile,CM,rCT,CaD and T score were also significantly correlated (r were 0.74, 0.65, 0.70, all P<0.01) with a linear relationship (F were 195.04,120.29,156.37,all P<0.01).CM,rCT and CaD had relatively high concordance rates against the OP diagnosis gold standard (respectively 81.9%, 62.2% and 81.9%). CM and CaD had higher concordance rates than rCT,the difference being statistically significant(P<0.01),and by the CM less than 239.5 HU or CaD less than 10.9 mg/cm3standard, their sensitivities of diagnosing osteoporosis were respectively 86.0% and 84.0%,while the specificities,80.2% and 81.0%.After superimposing CM and CaD, the results did not improve the diagnosis efficiency of OP (pre-superposition diagnostic performance better than post-superposition (P<0.05). Conclusion The VNC technology on DECT can do both vertebral fractures diagnosis and osteoporosis assessment at the same time, thus optimizing the clinical examination process.

Objective To investigate the application value of the quantitative parameters of collateral circulation based on computed tomography perfusion(CTP)in evaluating the clinical prognosis of patients with acute ischemic stroke(AIS).Methods A total of 126 patients with AIS caused by middle cerebral artery occlusion were enrolled,collateral circulation were reconstructed and scored via multiphase computed tomography angiography(mCTA)based on CTP.The hypoperfusion intensity ratio(HIR)and collateral vessel density(CVD)were calculated.All patients were divided into good prognosis group(72 cases)and poor prognosis group(54 cases)based on 90 d modified Rankin scale(mRS)scores.Differences in cardiovascular risk factors,National Institutes of Health Stroke Scale(NIHSS)scores,Albert stroke program early CT(ASPECT)scores,Tmax＞10 s volume,Tmax＞6 s volume,core infarct area volume,and final infarct volume between the two groups were compared.Binary logistic regression was employed to identify independent predictors of the clinical prognosis,and the DeLong test was used to compare the efficacy of different predictors in predicting clinical prognosis.Results The good prognosis group had significantly higher ASPECT scores,mCTA scores,and CVD,but significantly lower HIR,Tmax＞10 s volume,and baseline NIHSS scores compared to the poor prognosis group(P＜0.05).Binary logistic regression analysis showed that ASPECT scores[odds ratio(OR)=0.780],mCTA scores(OR=0.669),CVD(OR=0.595),and HIR(OR=28.968)were independent predictors of clinical prognosis(P＜0.05).DeLong test found no significant difference in area under the curve(AUC)values between mCTA scores,CVD and HIR in predicting the clinical prognosis of AIS patients(P＞0.05).Conclusion Quantitative parameters such as CVD and HIR related to collateral circulation have a strong diagnostic efficacy in predicting the 90 d clinical prognosis in patients with AIS.

Objective:To investigate the efficacy of a combined model constructed by the radiomics features based on non-contrast CT (NCCT) combined with clinical risk factors in predicting the occurrence of symptomatic intracranial hemorrhagic transformation (sICH) after intravenous thrombolysis with recombinant tissue plasminogen activator (rt-PA) in patients with anterior circulation acute ischemic stroke (AIS).Methods:In this cross-sectional study, clinical and imaging data of 316 patients with anterior circulation AIS who received intravenous thrombolysis with rt-PA at Nantong First People′s Hospital from October 2018 to September 2022 were retrospectively analyzed. The cases were divided into a training set of 210 cases and a validation set of 106 cases by stratified random sampling at a ratio of 7∶3. Univariate and multivariate logistic regression analyses were performed to select the independent clinical risk factors for predicting sICH. The infarct area was delineated on the NCCT images and radiomics features were extracted. The extracted radiomics features were dimensionally reduced and selected using the inter-and intra-group correlation coefficients, maximum correlation and minimum redundancy, and the least absolute shrinkage and selection operator, and then the radiomics score was calculated. Finally, multivariate logistic analysis was performed and the clinical risk factors and radiomics scores were used to establish the clinical model, the radiomics model and the radiomics-clinical combined model. The predictive efficacy of each model was evaluated by the receiver operating characteristic curve and the area under the curve, and decision curve analysis (DCA) was used to calculate and quantify the net benefits of each predictive model.Results:In total eight radiomics features were selected to construct the radiomics model. Multivariate logistic analysis showed that hypertension ( OR=2.703, 95% CI 1.153-6.334, P=0.022), atrial fibrillation ( OR=3.023, 95% CI 1.290-7.085, P=0.011), and the National Institutes of Health Stroke Scale score at admission ( OR=1.078, 95% CI 1.017-1.143, P=0.012) were independent risk factors for sICH after rt-PA intravenous thrombolysis in patients with anterior circulation AIS. In the validation set, the area under the curve of the combined model for predicting sICH was 0.763 (95% CI 0.618-0.909), which was higher than that of the clinical model 0.710 (95% CI 0.552-0.868) and the radiomics model 0.708 (95% CI 0.568-0.848). DCA showed that the combined model could allow patients to obtain higher net benefits. Conclusion:The combined model constructed based on the radiomics of NCCT and clinical risk factors has a high diagnostic efficacy in predicting sICH after rt-PA intravenous thrombolysis in patients with anterior circulation AIS.