CT能谱成像在胰岛素瘤诊断中的初步研究

Spectral CT imaging in preoperative diagnosis of pancreatic insulinoma:a preliminary study

目的:探讨CT能谱成像分析在胰岛素瘤诊断中的价值。方法:回顾性分析采用能谱CT能谱模式双期增强扫描并经手术病理证实的30例胰岛素瘤患者的病例资料。分别采用70keV单能图像、碘基图像和最佳keV能量图像进行重建,比较不同图像模式下胰岛素瘤的检出率和病灶的对比噪声比(CNR)。结果:本组胰岛素瘤动脉期和门静脉期70keV单能图像、最佳keV能量图像和碘基图像上CNR分别为3.18±2.21、3.77±2.37、3.13±2.18和1.77±1.25、2.20±1.38、1.87±1.08。配对t检验结果显示,70keV单能图像、最佳keV能量图像和碘基图的CNR,动脉期图像均明显优于门静脉期(t=3.139,P=0.005;t=3.196,P=0.004;t=3.05,P=0.003)。动脉期最佳keV能量图像上病灶CNR大于70keV单能量图像;动脉期和门静脉期70keV能量、最佳keV能量图像、碘基图、能谱多参数图像对胰岛素瘤的检出率分别为73.3%(22/30)、86.7%(26/30)、86.7%(26/30)、96.7%(29/30)和53.3%(16/30)、73.3%(22/30)、73.3%(22/30)、76.7%(23/30)。结论:在诊断胰岛素瘤方面,不同能谱扫描模式下动脉期图像均优于门静脉期,最佳keV能量图像和碘基图优于70keV单能量图像。能谱CT多参数图像联合应用有利于提高对胰岛素瘤的诊断准确性。

Objective：To explore the value of dual energy spectral CT imaging in preoperative diagnosis of insulinomas.Methods：Thirty patients included in this study underwent dual-phase DEsCT imaging from Feb 2010 to Nov 2011.All the patients had diagnosis confirmed by pathology.Three sets of spectral image including 70keV monochromatic image,iodine density image and optimal monochromatic image were reconstructed.All image sets were interpreted retrospectively by two radiologists.The contrast noise ratio（CNR） of lesion was calculated,and the detection rate of insulinoma and CNR were compared between different image sets.Results：In arterial phase,70keV monochromatic imaging detected 22 of 30 tumors and the optimal monochromatic imaging detected 26 of 30 tumors separately,the iodine density imaging also detected 26 of 30 tumors;while 29 of 30 tumors were detected with the combination of the three kinds of images.The CNRs of lesion on 70keV monochromatic image,optimal monochromatic image,iodine density image were 3.18±2.21,3.77±2.37,3.13±2.18 and 1.77±1.25,2.20±1.38,1.87±1.08.in arterial phase and venous phase respectively.The CNRs of lesion in arterial phase were significantly higher than those in portal venous phase,and CNR on optimal monochromatic image was higher than that on 70keV monochromatic image.Conclusion：The optimal monochromatic imaging has higher sensitivity in diagnosis of insulinomas compared with the 70keV mono-energy imaging and the iodine density imaging.The combination of monochromatic image and iodine density image can improve the diagnostic sensitivity of insulinomas.