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Objective:To explore the feasibility of quantitative evaluation of extracellular volume (ECV) fraction in acute ST-segment elevation myocardial infarction (STEMI) by dual-layer spectral detector CT.Methods:The clinical and imaging data of 20 patients with STEMI who underwent cardiac contrast-enhanced CT and MRI from January to October 2019 in Renji Hospital affiliated to Shanghai Jiaotong University School of Medicine were retrospectively analyzed.The dual spectral detector was used in the enhanced CT scan of the coronary artery with retrospectively gate and the late iodine enhancement with prospective gate. Conventional image and holographic spectral image were obtained by iterative and spectral reconstruction. The short axis image of the heart matched with MR image was obtained by multiplanar reconstruction. Based on the data of spectral based image, the IDD map was reconstructed for the calculation of myocardial CT-ECV during the late iodine enhancement. ECV of infarcted myocardium, salvageable myocardium and remote myocardium based on CT and MRI were calculated respectively. Bland-Altman consistency test and intra group correlation coefficient analysis (ICC) were used to compare the consistency of two measurements and different methods. The correlation between CT-ECV and MRI-ECV was compared by Spearman method.Results:The CT-ECV values of infarcted, salvageable, and remote myocardium were 51.21 (49.27, 53)%, 38.64 (36.17, 40)%, and 51.21 (49.27, 53)%, respectively. The difference was statistically significant ( H= 43.17, P<0.01). The CT-ECV value of infarcted myocardium was significantly higher than that of salvageable myocardium and remote myocardium ( Z=-24.60, 35.40, P<0.01), but there was no significant difference between salvageable myocardium and remote myocardium ( Z= 10.80, P=0.15). The T 1 values of infarcted myocardium, salvageable myocardium and remote myocardium were (1 554.85±70.94), (1 443.85±67.28) and (1 307.05±91.73) ms respectively, the difference was statistically significant ( F=51.35, P<0.01). The T 1 value of infarcted myocardium was higher than that of salvageable myocardium and remote myocardium ( t=-5.07, 9.55, P<0.01), and salvageable myocardium was significantly higher than that of remote myocardium ( t=5.38, P<0.01). The MRI-ECV values of infarcted myocardium, salvageable myocardium and remote myocardium were 55.00 (49.27, 57.75)%, 33.50 (29.00, 35.00)%,and 27.00 (26.00, 29.00)%, respectively. The difference was statistically significant ( Z= 47.12, P<0.01). MRI-ECV of infarcted myocardium was significantly higher than that of salvageable myocardium and remote myocardium ( Z=37.45, -20.30, P< 0.01), and salvageable myocardium was significantly higher than that of remote myocardium ( Z = 17.15, P<0.05). The difference between CT-ECV and MRI-ECV measured by two physicians was good. The bias of Bland-Altman analysis was -0.1% (95% CI:-5.5%-5.2%), 0.8% (95% CI:-9.8%-8.2%), and the ICC values were 0.92 and 0.94, respectively. The bias of Bland-Altman analysis in CT-ECV and MRI-ECV consistency test was 4.00% (95% CI:-9.0%-16.9%) and ICC value was 0.88, which had a good correlation ( r=0.75, P=0.001). Conclusions:The iodine density based ECV fromdual-layer spectral detector CT can be used to quantitatively evaluate the changes of extracellular space after acute STEMI, which is helpful to quantitatively evaluate the histological changes after myocardial ischemia.
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Objective To evaluate the feasibility of diffusion kurtosis imaging (DKI)in the diagnosis and aggressiveness assessment of prostate cancer.Methods The MR data with multi-b-value diffusion-weighted imaging (DWI)of 30 male patients with prostate cancer were retrospectively analyzed.D maps and K maps were generated from the DKI model and ADC maps were obtained using the conventional monoexponential model.Differences in the D,K and ADC values between prostate cancer and benign peripheral zone (PZ)tissues,among tumors with different Gleason scores were analyzed.P<0.05 was considered statistical significance.Results ADC and D values were significantly lower in the prostate cancers than in the benign PZs (P <0.001).K values were significantly greater in the prostate cancers than in the benign PZs (P <0.001).ADC,D and K values were different significantly among the tumors with Glea-son scores of 6,7 and ≥8 (P <0.001,P =0.01 5 and P <0.001,respectively).Conclusion The DKI model can better describe the signal intensity attenuation with b values increasing,which is helpful for diagnosing and grading prostate cancer.K value may be used to quantitatively evaluate the complicated microstructure of prostate cancer.
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In the educational reform of radiology,the importance of practical skills training has increasingly become the focus of teaching.As a symbol of medical imaging informationization,PACS provides solid material foundation for teaching reform,making it possible to establish a large capacity and stability of a picture library.By making full use of all intemet teaching resources and improveing teaching methods,teachers have more communication with students through PBL and CBL teaching.Therefore,students get deeper understanding and better ability to put the theory of knowledge into practice and the teaching effect is pretty good.