能谱CT单能量成像诊断活动性小肠出血的实验研究  

Evaluation of monochromatic imaging spectal CT for intestinal bleeding using an experimental pig intestine model

作　　者：刘文冬[1] 吴兴旺[1] 刘斌[1] 李红文[1] 王斌[2] 

机构地区：[1]安徽医科大学第一附属医院放射科,合肥230022 [2]安徽医科大学流行病与卫生统计学系

出　　处：《中华放射学杂志》2014年第7期594-598,共5页Chinese Journal of Radiology

基　　金：安徽省高校省级自然基金重点资助项目（KJ2011A179）

摘　　要：目的 探讨能谱CT单能量成像诊断小肠活动性出血的价值,以及显示肠道活动性出血的最佳单能量值.方法 离体猪小肠和微量注射器连接,分别设置7种注射流率（分别为0.500、0.400、0.300、0.200、0.100、0.050、0.025 ml/min）模拟活动性小肠出血.分别对上述模型进行普通模式及能谱成像（GSI）模式扫描,每个流率扫描5次.延迟15、40 s扫描分别模拟动脉期和门静脉期.普通模式扫描得到混合能量图像,对GSI模式扫描图像进行重建得到40、50、60、70、80、90和100 keV共7种单能量图像.观察不同扫描模式和期相图像的对比噪声比（CNR）,同时记录不同扫描模式下对比剂渗出的检出结果.对不同期相和扫描模式图像的CNR比较采用方差分析,对比剂渗出检出情况的比较采用x2检验.结果 动脉期,普通模式和GSI模式对比剂渗出的检出情况（分别为23/35和31/35）差异有统计学意义（x2=5.185,P=0.023）;门静脉期,2种模式的检出情况（分别为32/35和35/35）差异无统计学意义（x2=1.393,P=0.238）.普通模式下,动脉期和门静脉期的检出情况差异有统计学意义（x2=6.873,P=0.009）; GSI模式下,动脉期和门静脉期检出情况差异无统计学意义（x2=2.386,P=0.122）.动脉期和门静脉期,8组能量图像CNR差异均有统计学意义（P均＜0.05）,GSI模式50和60 keV单能量图像对比剂渗出区的CNR值高于混合能量图像,差异有统计学意义（P均＜0.05）,各能量组门静脉期图像CNR均高于动脉期像,差异均有统计学意义（t值为-3.996～-2.380,P均＜0.05）.结论 能谱CT单能量成像诊断小肠活动性出血的价值优于普通CT,最佳单能量值为50、60 keV,且门静脉期优于动脉期.Objective To discuss the diagnostic value of monochromatic energy image spectral CT in active small bowel bleeding and to screen the optimal energy level that indicates active bleeding of the gastrointestinal tract.Methods The bleeding model was established using the small intestines of pigs in vitro.Seven blood flow rates were simulated：0.500,0.400,0.300,0.200,0.100,0.050,0.025 ml/min,respectively.For each rate,a GE Discovery HD750 CT scanner was used in GSI scan mode and 64 slice CT was performed,with a delay of 15 s and 40 s simulated the arterial phase and portal venous phase,respectively.Each out of the blood flow rate in the 2 modes was respectively scanned 5 times.The GSI reconstruction platform was employed to obtain 7 monochromatic energy images（40,50,60,70,80,90,100 keV）.A set of polychromatic energy images was obtained from an ordinary scan.The detection rates of the contrast agent exudation regions using the two scanning methods were compared.The contrast to noise ratios（CNR） for the contrast agent exudation regions were measured.Randomized block analysis of Variance was performed to compare the differences in CNR between energy levels.The x2 test was used to compare the detection rates obtained from the 2 scanning methods.Results The detection rates for energy spectral CT and 64 slice CT in the arterial phase were 31/35 and 23/35,respectively; there was significant difference（x2=5.185,P=0.023）.The total detection rates of portal venous phase were 35/35 and 32/35,respectively,there was no significant difference（x2=l.393,P=0.238）.On the ordinary scan mode,the detection rates of arterial and portal venous phase difference was statistically significant（x2 =6.873,P =0.009）;but on the GSI scan mode,there was no significant difference（x2=2.386,P=0.122）. The CNR values at 8 group energy levels for arterial phase and portal venous phase were statistically different（respectively P＜ 0.05）,the CNR value of the contrast agent exudation regions at 50 keV and 60 keV monochromatic ene

关 键 词：胃肠出血 体层摄影术 X线计算机 能谱成像 

分 类 号：R816.5[医药卫生—放射医学] R574.5[医药卫生—临床医学]