探讨腹部CT增强能谱成像碘对HAP(Iodine)/HAP(Water)/HAP(Fat)密度测量值影响

To investigate the effect of Iodine on density measurement of HAP-(Iodine), HAP-(Water) and HAP-(Fat) in abdominal CT enhanced with energy spectrum imaging

目的:探究碘对比剂对能谱CT基物质成像HAP(Iodine)、HAP(Water)、HAP(Fat)密度测量值的影响,寻找增强扫描中可用于骨密度测量参考的基物质对。方法:回顾性搜集基于BMI行个体化全腹部能谱(GSI)增强扫描患者214例,男135例、女79例,年龄16~85岁,记录每位患者的碘摄入量。临床采用4期(平扫期、动脉期、静脉期、延迟期)GSI扫描,获得图像数据传输到AW4.7工作站,应用GSI后处理软件重组各期的HAP(Iodine)、HAP(Water)、HAP(Fat)基物质图像,测量并记录4期图像中第三腰椎椎体骨松质的HAP(Iodine)、HAP(Water)、HAP(Fat)密度值。采用配对样本t检验分别对HAP(Iodine)、HAP(Water)、HAP(Fat)各期密度测量值进行两两比较;对患者碘摄入量与增强3期HAP(Iodine)密度测量值行Pearson相关分析。结果:4期HAP(Water)、HAP(Fat)值差异均有统计学意义(P<0.05),而4期HAP(Iodine)值差异无统计学意义(P>0.05),4期HAP(Iodine)值分别为693.49±20.29、693.39±20.30、693.18±20.14、693.19±20.44,单位为2mg/cm3;碘摄入量与增强3期HAP(Iodine)密度测量值均无相关性(P>0.05)。结论:HAP(Water)、HAP(Fat)测量值受碘对比剂影响较大,而HAP(Iodine)测量值不受碘对比剂影响,4期中HAP(Iodine)测量值趋于稳定。HAP(Iodine)测量值可用作平扫与增强扫描评估骨密度的参考。

Objective:To investigate the effect of iodine contrast agent on the density measurement of HAP-(Iodine),HAP-(Water)and HAP-(Fat)with dual-energy spectral CT basis material imaging.To search the basis material pair that would be used as a reference for bone mineral density measurement in the CT enhanced scanning.Methods:The image data of 214 patients(ages 16 to 85 years,135 males and 79 females)who were underwent abdominal enhance scanning with Gemstone spectral image(GSI)based BMI scan protocol were collected retrospectively.The dose of injection iodine were recorded.Every patients was underwent with CT GSI including 4 phases scan(plain-,arterial-,portal venous-,and delayed phases).The acquisition image were send to the AW4.7 work station.The four phase basis material image of HAP-(Iodine),HAP-(Water)and HAP-(Fat)were reconstructed with GSI post-processing software.The HAP densities of HAP-(Iodine),HAP-(Water)and HAP-(Fat)of the third lumbar vertebrae spongy bone in each scan phases were measured and recorded.The differences of HAP-(Iodine),HAP-(Water)and HAP-(Fat)densities value in each phases were compared with Paired-samples T test statistically.The correlation analysis were performed between iodine injection dose and value of HAP-(Iodine)in arterial-,portal venous-,and delayed phases with Pearson correlation analysis.Results:The HAP density values which were measured with HAP-(Water)and HAP-(Fat)basis material pairs in four phase are significant different(P<0.05).The HAP density values which were measured with HAP-(Iodine)basis material pairs in four phase are no significant different(P>0.05).The HAP-(Iodine)density values in four phases were 693.49±20.29(2mg/cm 3),693.39±20.30(2mg/cm 3),693.18±20.14(2mg/cm 3)and 693.19±20.44(2mg/cm 3),respectively.There was no significant correlation between iodine injection dose and the value of HAP-(Iodine)in post-enhanced phases(P>0.05).Conclusion:The bone mineral density value which were measured with HAP-(Water)or HAP-(Fat)may be impacted by injection Iodine contrast agent.While it maybe no impact on the measurement with HAP-(Iodine).The bone density value of HAP-(Iodine)in four phases imaging is stable.The bone mineral density value which were measured with HAP-(Iodine)among pre and post enhancement with GSI scan may be a valuable reference for evaluation bone density.