The Feasibility Of Contrast Agent Dose Reduction With Low Tube Voltage And High Tube Current-time Product Settings At MSCT In CcRCC

Objective:The purpose of this study was to investigate feasibility of the contrast agent dose reduction with the low tube voltage and the appropriate high tube current-time product settings at MSCT in cc RCC of the multiphase enhancement scanning.Materials and Methods:According to our research needs,we chose the 60 patients doubted renal lesions performed with abdominal multiphase enhancement sacn CT,and whom pathology confirmed for renal clear cell carcinoma patients.Comply with any of the following a standard is not included:(1) For severe renal failure(GFR < 30 ml/min);(2)The iodine contrast agent allergic patients;(3) Proved or suspected was pregnant;(4)The patients with BMI≧28 kg/m2;(5)Cardiac insufficiency(grade III or IV).According to doctor order,we classfied the patients for the double low group and the routine group,30 cases in each group.Using GE 64 row of Light Speed VCT CT and the Ad W 4.6 to deal with images.Scan parameters respectively 90 k V550, m A and 120 k Vautomatic, tube current control technology;The contrast agent using iodine(300 mg/ml),the double low group contrast agent dose was 1.0 ml/kg,the routine group was 1.5 ml/kg.The scan range is from the diaphragmatic top level to the pubic symphysis;Monitoring 1 lumbar vertebral of abdominal aorta ROI value to 150 Hu,CMP images acquisition,after about 30 s NP images was taken.To evaluate the image points respectively:(1)Four points scored to analysisthe quality of the CMP and NP images;(2)To measure and record the ROI of the tumors,therenal parenchyma,and the renal vein,abdominal subcutaneous fat SD value,and then calculated SNR,CNR;(3)To observed the relationship of the tumor,the renal adipose capsule,the one side renal vein and the lymph nodes;Four,To record the contrast agent dose and DLP. Application SPSS17.0 software for the data analysis.Results:The quality of all the images can meet the needs of the clinical diagnosis. Subjective image quality score CMP the double low group 3 points 2,4 points 28,and the conventional group 3 points 3,4 points 27;NP the double low group 3 points 3, 4 points 27 and the normal group 3 points 2,4 points 28;The the double low group ROI value of the tumor,the renal vein,but the differences was no statistically significant(P>0.05);differences of CNR and SNR was no statistically differences(P > 0.05); The contrast medium doses of the double low group is less than the ones of conventional group about 33.33%; Two groups of CMP DLP were 531.99±86.96(m Gy·cm) and617.08±107.91(m Gy·cm), NP DLP were 549.66±76.70(m Gy·cm) and638.09±95.63(m Gy·cm), the differences was statistically(P<0.05), a drop of CMP NP DLP is about 13.79% and 13.79% respectively.Two groups of CMP ED were 8.51±1.39(m Sv),11.11±1.94(m Sv) respectively,the differences was statistically(P<0.05),the double low group decreased about 23.40%; NP ED were 8.79±1.22(m Sv), 11.49±1.72(m Sv),the double low group decreased about 23.50%; the double low group and the routine group the tatal ED were 17.31±2.51(m Sv), 22.59±3.50(m Sv)), and the double low group total ED decreased about 23.37%.Conclusion:(1) The application of MSCT low iodine contrast medium doses lower tube voltage,appropriate executive current technique in patients with normal body mass index of renal clear cell carcinoma lesions showed good;(2)The scanning could understand to cc RCC of the T staging;(3) The doses of radiation and contrast agent reduced at the same time withthe decline of 33.33%,23.37% respectively.The scanning is suitable especially for children,the slim adults and the ones who with kidney damages.