摘要
Objective To observe the value of electron density map(EDM)from spectral CT combined with CT features in differentiating acute and chronic osteoporotic vertebral fractures(OVF).Methods Thoracic and/or lumbar spectral CT data of 48 patients with acute complicated chronic OVF were retrospectively analyzed.Totally 110 fractured vertebrae were enrolled,including 53 vertebrae with acute fractures(acute group)and 57 with chronic fractures(chronic group).The quantitative parameters of spectral CT,including CT values of conventional 120 kVp polyenergetic image(PI,i.e.routine CT images)and 40,70,100 keV virtual monoenergetic images(VMI),effective atomic number(Z-eff)and electron density(ED),as well as routine CT finding were compared between groups,and those being significantly different were included in multivariate logistic regression to screen the independent risk factors for acute OVF and construct a combined model.Receiver operating characteristic(ROC)curves were drawn to evaluate the efficacy of each single independent risk factor and the combination for differentiating acute and chronic OVF.Results Significant differences of all spectral CT quantitative parameters,also of routine CT findings including interruption of vertebral endplate,cortical folds,increased vertebral density,gas within vertebral body and vertebral compression degree were found between groups(all P＜0.05).Logistic regression analysis showed that CTPI(OR=0.855,P=0.005),ED(OR=16.432,P=0.005),cortical folds(OR=0.038,P=0.034)and increased vertebral density(OR=0.025,P=0.013)were all independent risk factors for acute OVF.The area under the curve(AUC)of the above single parameters for identifying acute and chronic OVF was 0.870,0.889,0.879 and 0.866,respectively,all lower than that of the combined model(0.977)(Z=3.47,3.73,2.95,2.71,all P＜0.05).Conclusion Spectral CT EDM combined with CT findings could effectively differentiate acute and chronic OVF.
摘要
Objective To evaluate the feasibility of dual-source low-dose computed tomography (CT) of the paranasal sinus in children, with acquisition at an ultra-low tube voltage (70 kVp) combined with the Flash scan. Methods CT scans of the paranasal sinus were performed on 80 pediatric patients who were divided into two groups according to different protocols (70 kVp protocol with Flash scan mode and the iterative reconstruction, pitch 3, the experimental group (group A), n = 40; 80 kVp protocol with conventional spiral mode, pitch 1.5, control group (group B), n = 40). For each examination, the CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED) were estimated. The image noise, signal-to-noise ratio (SNR) and overall subjective diagnostic image quality were also evaluated. Results The images of these two groups were all satisfied for the clinical diagnosis. For radiation dose, the CTDIvol (mGy), DLP (mGycm) and ED (mSv) values of the 70 kVp protocol were significantly lower than those of the 80 kVp protocol [CTDIvol: 0.39 ± 0.004 vs1.57 ± 0.009 mGy, P < 0.001; DLP: 6.31 ± 0.52 vs 19.88 ± 2.01 mGycm, P < 0.001; ED: 0.024 ± 0.005 vs 0.079 ± 0.016 mSv, P < 0.001. Compared with those of the 80-kVp protocol, the image noise and the SNRbone increased, the SNRsoft-tissue decreased. There was no statistical difference in the subjective scores of the two groups of image quality by the two physicians (P > 0.05). Conclusion When diagnosing the paranasal sinus in children, an ultralow tube voltage (70 kVp) combined with the Flash scan technique can reduce the radiation dose significantly while maintaining diagnostic image quality with clinically acceptable image noise.
摘要
Objective To explore the diagnosis value of dual energy CT in severity analysis of acute pancreatitis.Methods Pancreas CT perfusion images of 60 patients were formatted using the method of Siemens dual energy CT.According to the severity of the acute pancreatitis,60 patients were divided into 3 groups:normal control (NC)group,mild acute pancreatitis (MAP)group and severe acute pancreatitis (SAP)group.Every group had 20 patients.Blood flow(BF),blood volume(BV),permeability of capillary surface (PS)and mean transit time(MTT)were calculated by Siemens MMWP workstation post process software.The meaning of these CT perfusion parameters for severity of acute pancreatitis was analyzed.Results Compared to the NC group,BF and BV in MAP,SAP group were reduced significantly (P 0.05).We also found in ≥45 years old patients,MTT in both MAP and SAP groups were higher than NC group(P <0.05).Conclusion (1)BF and BV are useful in diagnosis of acute pancreatitis and analysis of severity of it.(2)PS is useful in diagnosis of acute pancreatitis.(3)MTT is useful in diagnosis of acute pancreatitis in elderly patients (≥45 years old).