Objective To evaluate the correlation between multi-slice spiral CT(MSCT)perfusion imaging parameters and gastric carcinoma differentiation.Methods MSCT perfusion parameters including blood flow(BF),patlak blood volume(PBV),time to peak (TTP)and patlak permeability surface(PPS)were obtained in 44 patients with pathologically confirmed gastric carcinoma before sur-gery.Patients were divided into two groups;26 well differentiated and 18 poorly differentiated.According to the extent of cell differ-entiation ,BF,PBV,TTP and PPS were investigated in two groups.Results Parameters in the well differentiated gastric carcinoma group BF 101.8±6.7 (mL·min-1 ·100 mL-1 ),PBV 85.9±3.4 (mL/1 000 mL ),TTP 121.6±1 1.5(0.1 s),PPS 82.7±1 1.0 (0.5 mL·min-1 ·100 mL-1 )respectivily,Parameters in the poorly differentiated gastric carcinoma group,BF 105.3 ±7.7,PBV 92.1±7.1,TTP 113.0±10.5,PPS 94.3±22.9 respectivily.There was no statistic difference in BF value between the two groups(P >0.05). There were statistic differences in TTP、PBV and PPS between the two groups(P <0.05).Conclusion MSCT perfusion parameters may reflect the degree of differentiation of gastric carcinoma or a certain extent in vivo.

【Objective】 To investigate the safety and efficacy of flexible vacuum aspiration ureteral access sheath in ureteroscopic lithotripsy in the treatment of renal and upper ureteral calculi. 【Methods】 Clinical data of 41 cases treated in our hospital were retrospectively analyzed, including 20 cases treated with flexible vacuum aspiration ureteral access sheath (experimental group), and 21 cases treated with traditional ureteral access sheath (control group). The stone-clearance rate, operation time, postoperative fever (T>37.5 ℃), length of hospital stay and hospitalization costs were compared between the two groups. 【Results】 All operations were successful. The experimental group had significantly shorter operation time than the control group [(54.0±19.8) min vs. (76.6±20.1) min, P<0.05], higher stone-clearance rate (90.0% vs. 61.9%, P<0.05), and lower incidence of postoperative fever (0 vs. 23.8% P<0.05). There were no significant differences in hospital stay and costs between the two groups (P>0.05). 【Conclusion】 Flexible vacuum aspiration ureteral access sheath in flexible ureteroscopic lithotripsy can shorten the operation time, improve stone-clearance rate and reduce incidence of postoperative fever, which is worth promoting.