ABSTRACT
Objective To evaluate the value of material decomposition imaging of spectrum CT in overcoming renal cyst pseudoenhaneement.Methods Totally 80 patients with renal cysts (total 75 cysts) who underwent CT imaging with GSI mode were collected.The renal cysts were divided into 3 groups according to diameters,group A (diameters 0.5-＜1.5 cm,n=25),B (1.5-＜2.5 cm,n=25) and C (2.5-＜3.5 cm,n=25) respectively.The iodine-water density imaging was reconstructed by using the GSI Viewer analysis software.The CT value and iodine-water concentration of the cysts were recorded.The difference of CT value,iodine-water concentration in unenhanced and enhanced dual phases in each group was compared.Results The difference of CT value between plain scan and parenchyma phase among the 3 groups had statistically significant difference (F=204.128,P＜0.001),and the differences comparing any two were statistically significant (all P＜0.05).The postcontrast attenuation increased more than 10 HU in group A and B,indicating renal cyst pseudoenhancement,and less than 10 HU in group C,which had no pseudoenhancement.There were statistical difference in iodine concentration of the cysts of the 3 groups in unenhance,cortical and parenchyma phases (all P＜0.001),but the difference value in unenhance,cortical and parenchyma phases were less than 10 (100 μg/cm3),and the difference value of the 3 group was group A＞group B＞group C (all P＜0.05).The water concentration of the cysts in group A descend in renal cortical and parenchyma phase with statistical difference (P＜0.001),but the difference value was less than 10 mg/cms.Conclusion The measurements of iodine-water concentration appear to drift as well,the smaller the greater,The degree of the iodine concentration shifting is more obvious than water concentration.