In order to analyze and study the hemolysis performance of the centrifugal maglev blood pump, which was designed by ourselves, this paper built the mathematical model and computational fluid dynamics analyzed it using Fluent. Then we set up the in vitro hemolysis experiment platform, in case of the design condition, the content of free hemoglobin and hematocrit in plasma were measured in a certain time interval, and calculated the normalized index of hemolysis of the blood pump. The numerical simulation results show the internal static pressure distribution is smooth inside the pump, the wal shear stress inside the pump is less than 150 Pa. Therefore, the red blood cel damage and exposure time is independent. The normalized index of hemolysis is (0.002 9±0.000 7) mg/L, which is in accordance with human physiological requirement.

Objective:To investigate the impact of the interval period between biopsy and MR examination on tumor detection and extraprostatic extension (EPE) assessment for prostate cancer (PCa) using multi-parametric MRI (mpMRI).Methods:The study was cross-sectional and retrospectively included 130 patients with PCa who underwent RP and preoperative systematic biopsies followed by mpMRI between January 2021 and December 2022 in the First Medical Center of Chinese PLA General Hospital. Patients were divided into 3 groups according to interval following biopsy (group A,<3 weeks, 31 cases; group B, 3-6 weeks, 67 cases; group C,>6 weeks, 32 cases). The percentages of hemorrhage volume in the total prostate were drawn on T 1WI and calculated. The junior, senior and expert radiologists independently localized the index lesions and calculated the accuracy for tumor detection, in addition to assessing the probabilities of EPE according to EPE grade. The correlation between the hemorrhage extent and interval was analyzed using the Spearman correlation coefficient. The accuracy for tumor detection was compared using χ2 test among groups. The diagnostic performance of the radiologists for EPE prediction was assessed using the receiver operating characteristic curve, and the differences between the corresponding area under the curve (AUC) were compared using the DeLong test. Results:The percentage of hemorrhage was correlated with the interval between biopsy and MR examination ( r=-0.325, P<0.001). The detection accuracy of junior radiologist was 83.9% (26/31), 76.1% (51/67), and 78.1% (25/32) in group A, B and C, respectively; no differences were observed in the detection accuracy among three groups ( χ2=0.76, P=0.685). The detection accuracy of senior radiologist was 83.9% (26/31), 80.6% (54/67), and 71.9% (23/32) in 3 groups with no differences ( χ2=1.53, P=0.464). The detection accuracy of expert radiologist was 80.6% (25/31), 77.6% (52/67), and 93.8% (30/32) with no differences ( χ2=3.95, P=0.139). The AUC (95% CI) for predicting EPE were 0.830 (0.652-0.940), 0.704 (0.580-0.809), 0.800 (0.621-0.920) in the group A, B and C for junior radiologist; 0.876 (0.708-0.966), 0.768 (0.659-0.863), 0.896 (0.736-0.975) for senior radiologist; and 0.866 (0.695-0.961), 0.813 (0.699-0.895), 0.852 (0.682-0.952) for expert radiologist, respectively. No differences were observed among the subgroups in each radiologist ( P>0.05). Conclusion:The interval period does not significantly affect the detection accuracy and EPE assessment of PCa using mpMRI. There is probably no necessity for prolonged intervals following systematic biopsy to preserve the clarity of MRI interpretation for PCa.

Purpose To explore the diagnostic value of prostate imaging report and data system 2.1(PI-RADS v2.1)combined with prostate-specific antigen density(PSAD)for clinically significant prostate cancer(csPCa)in prostate-specific antigen(PSA)gray area(4-10 ng/ml)based on two-center data.Materials and Methods The clinical and imaging data of patients with PSA gray zone prostate disease who underwent multi-parametric magnetic resonance imaging and all pathological data in the First Medical Center(center 1)and the Sixth Medical Center(center 2)of the Chinese PLA General Hospital from January 2017 to May 2022 were retrospectively selected and analyzed.The patients from center 1 were used as the training group(220 cases),and the patients from center 2 were used as the test group(50 cases).Logistic regression was used to determine the independent predictors of csPCa in the training group,and the diagnostic efficacy of multi-parameter combination for csPCa was analyzed,which was further verified in the test group.Results There were significant differences in prostate volume,PSAD and PI-RADS v2.1 scores between the csPCa and non-csPCa groups in the training group(Z=-6.468,6.589,75.676,all P＜0.001).Logistic regression analysis showed that PI-RADS v2.1 score and PSAD were the independent risk factors for csPCa(both P＜0.001).The area under the curve of the Logistic regression model composed of PI-RADS v2.1 and PSAD for predicting csPCa in the PSA gray zone was 0.860(95％CI 0.808-0.903)in the training group and 0.906(95％CI 0.790-0.970)in the test group,respectively.The area under the curve of Logistic regression model was significantly higher than that of PI-RADS v2.1 and PSAD,respectively,with statistically significant difference(both P＜0.05).When the PI-RADS v2.1 score was low or moderate risk and PSAD＜0.15 ng/ml2,csPCa in the training group and the test group was with low detection rate.Conclusion PI-RADS v2.1 score and PSAD may be the independent risk factors for predicting csPCa in the PSA gray zone.The combined application of the two methods is better than the single method in the diagnosis of csPCa in the PSA gray zone,with benefits for clinical biopsy decision-making.