第3代双源CT低剂量胰腺CT灌注成像初探

The preliminary study of low dose pancreatic perfusion CT on third-generation dual-source CT

目的:探讨第3代双源CT低剂量胰腺灌注成像的参数特点及可靠性。方法:前瞻性收集24例正常胰腺受检者,行上腹部增强CT及CT胰腺灌注检查,按不同低剂量扫描方案,将受检者随机分成两组(A组:管电压70kV,管电流100mA,进行27次连续动态数据采集;B组:管电压80kV,管电流80mA,进行29次连续动态数据采集),每组12例。由两位放射科医师独立测量胰腺头部、体部、尾部的血流量(BF)、血容量(BV)、平均通过时间(MTT)、达峰时间(TTP)和表面通透性(PS),记录、计算辐射剂量并进行统计学分析。结果:两位观察者测得各部位所有灌注参数的一致性良好(ICC均>0.75);A组各参数值的ICC分别为:BF(0.949～0.968)、BV(0.941～0.977)、MTT(0.843～0.873)、PS(0.857～0,944)、TTP(0.859～0.897);B组各参数值的ICC分别为:BF(0.908～0.984)、BV(0.858～0.974)、MTT(0.837～0.955)、PS(0.909～0.964)、TTP(0.783～0.944)。正常胰腺头部、体部和尾部的不同参数之间及A、B两组的胰腺组织血流灌注参数之间差异均无统计学意义(P值均>0.05);各灌注参数的测量值及统计学分析结果:BF:139.36～155.43mL/(100mL·min),F=0.417,P=0.835;BV:16.86～18.90mL/100mL,F=0.308,P=0.906;MTT:7.27～8.41s,F=1.819,P=0.121;PS:66.76～77.32mL/(100mL·min),F=0.430,P=0.826;TTP:7.41～8.51s,F=2.293,P=0.055。两个年龄组(<60岁组、≥60岁组)的胰腺组织灌注参数差异无统计学意义(P>0.05);两个年龄组各灌注参数的测量值及统计学分析结果:BF:(138.39±41.43)vs(143.30±43.69)mL/(100mL·min),P=0.106;BV:(17.52±5.08)vs(18.44±4.59)mL/100mL,P=0.647;MTT:(7.92±0.99)vs(7.76±1.71)s,P=0.784;PS:(67.70±23.16)vs(72.61±17.46)mL/(100mL·min),P=0.569;TTP:(8.08±0.77)vs(7.97±1.42)s,P=0.819。不同性别间胰腺组织灌注参数除MTT[女性为(7.33±1.20)s,男性为(8.69±1.17)s,P=0.013]差异有统计学意义外,其余参数差异均无统计学意义(P>0.05);两组间各灌注参数的测量值及统计学分析结果:BF:(133.01±29.53)vs (145.23±39.32)mL/(100mL·min),P=0.341;BV:(19.01±4.76)vs(17.31±4.83)mL/100mL,P=0.411;PS:(71.40±27.70)vs(69.08±15.72)mL/(100mL·min),P=0.795;TTP:(8.58±1.08)vs(7.70±0.99)s,P=0.053。灌注期有效辐射剂量:A组DLP为616.7mGy·cm,有效辐射剂量为9.25mSv;B组DLP为871.7mGy·cm,有效辐射剂量为13.07mSv。结论:第3代双源CT可实现胰腺低剂量灌注扫描,并能获得稳定、重复性好的灌注参数值。

Objective: To study the characteristics of the normal pancreas measured by low-dose pancreatic CT perfusion on a third-generation dual-source CT,and to evaluate the reliability of CT perfusion parameters. Methods: Twenty-four subjects with normal pancreas underwent upper abdominal CT enhanced scan and low-dose whole pancreas CT perfusion scan.The subjects were randomly divided into two groups according to different scanning schemes (group A:70kV,100mA;group B:80kV,80mA).In addition,they were grouped according to age and sex.Blood flow (BF),blood volume (BV),mean transit time (MTT),time to peak (TTP) and permeability of surface (PS) in the head,body and tail of pancreas were measured independently by two radiologists.Effective radiation dose was calculated and statistically analyzed. Results: The good consistency was observed in all perfusion parameters between two groups (all ICC>0.75):BF [(139.36±38.53)mL/(100m L· min)^(155.43± 23.27)mL/(100m L· min), F =0.417, P =0.835],BV[(16.86±3.03)mL/100mL^(18.90±5.94)mL/100mL, F =0.308, P =0.906],MTT[(7.27±1.41)s^(8.41±1.03)s, F =1.819, P =0.121],PS[(66.76±17.10)mL/(100mL·min)^(77.32±23.19)mL/(100m L· min), F =0.430, P =0.826], TTP[(7.41± 1.00)s ^(8.51±0.96)s, F =2.293, P =0.055].There was no significant statistical difference for BF、BV、MTT、TTP and PS of the head,body and tail of the normal pancreas,and no significant difference on CT perfusion parameters between group A and group B ( P >0.05):BF[(139.36± 38.53)mL/(100m L· min)^(155.43±23.27)mL/(100m L· min), F =0.417, P =0.835],BV[(16.86±3.03)mL/100mL^(18.90±5.94)mL/100mL, F =0.308, P =0.906],MTT[(7.27±1.41)s^(8.41±1.03)s, F =1.819, P =0.121],PS[(66.76±17.10)mL/(100m L· min)^(77.32±23.19)mL/(100m L· min), F = 0.430, P =0.826],TTP[(7.41±1.00)s^(8.51±0.96)s, F =2.293, P =0.055].There was no statistical difference in all perfusion parameters between different age groups (≥60 years old,< 60 years old)( P >0.05):BF[(138.39±41.43)mL/(100m L· min) vs (143.30±43.69)mL/(100m L· min), P =0.106],BV[(17.52±5.08)mL/100mL vs (18.44±4.59)mL/100mL, P =0.647],MTT[(7.92±0.99)s vs (7.76±1.71)s, P =0.784],PS[(67.70±23.16)mL/(100m L· min) vs (72.61± 17.46)mL/(100m L· min), P =0.569],TTP[(8.08±0.77)s vs (7.97±1.42)s, P =0.819].No statistically significant differences in all perfusion parameters were noted between male and female groups ( P >0.05): BF[(133.01±29.53)mL/(100m L· min) vs (145.23±39.32)mL/(100m L· min), P = 0.341), BV[(19.01±4.76)mL/100mL vs (17.31±4.83)mL/100mL, P =0.411],PS[(71.40± 27.70)mL/(100m L· min) vs (69.08±15.72)mL/(100m L· min), P =0.795],TTP[(8.58±1.08)s vs (7.70±0.99)s, P =0.053],except for the MTT between male (8.69±1.17s) and female(7.33± 1.20s). The effective radiation dose of the whole pancreas CT perfusion of Group A and Group B were 9.25 and 13.07mSv (DLP 616.7 and 871.7mGy·cm),respectively. Conclusion: Low-dose pCTP is feasible on third-generation dual-source CT,which can obtain stable and reproducible perfusion parameters .