Study Of MSCT Urography As A One-stop Shop

PART1LOW RADIATION DOSE AND CONTRAST PROGRAMSSECTION1STUDY ON LOW RADIATION DOSE PROGRAM OFPHANTOM USING MSCTObjective: To evaluate the effect of different voltage and noise indexon radiation dose of different body thickness in phantom using currentautomatic regulation technology.Methods: Scanned the home made cone phantom segmentely andconstantly, from the top to the button, simulate patients with differentbody thickness segmentely,5layers a segment, get images of every segmentof different tube voltage（140kV,120kV,100kV,80kV）and different noiseindex （10-20）, and recorded volume computed tomography doseindex(CTDIvol).Results:1.When the average body thickness less than126.2mm,noise index of10to12, CTDIvol was lowest if the tube voltage was80kV.2. When the average body thickness below126.2mm, noise index of12to20, CTDIvol was lowest if the tube voltage was120kV. When the averagebody thickness no less than126.2mm, the noise index of10to20, CTDIvol was lowest if the tube voltage was120kV. Then the regression equationwas established:CTDIvol=0.511+0.081×thickness-0.709×noiseindex+0.004×voltage，the coefficient of overall model, the thickness andthe noise index were tested (p<0.001), and the coefficient of distance andvoltage were tested respectively (p=0.49,0.42).Conclusion: Using the current automatic regulation technology, theradiation dose (CTDIvol) increased with the increase of the phantomthickness, and decreased with the increase of the noise index, and there wasno significant correlation with tube voltage, but the radiation dose can bereduced by using tube voltage of120kV through data observation withinthe range of adult thickness. SECTION2STUDY ON THE LOW CONTRAST PROGRAMS USINGMSCTObjective: To explore the feasibility of using low contrast and kVprograms in MSCT Urography as a One-Stop Shop.Methods:80cases who took the MSCT Urography as a One-StopShop scan was divided into four groups randomly （group A1.5mL/kg 120kV, group B1.0mL/kg120kV, group C0.8mL/kg120kV, group D0.8mL/kg80kV）. Evaluated main renal arteries and their first-order tofourth-order branches, scored from0to2.Rated urinary system imagequality （I, II, III）, measured CT values of the aorta and musclerespectively at arterial phase，calculated the enhancement of aortic andcontrast-to-noise ratio(CNR).Results: There is no significant difference（p>0.05） between groupA left7.25±1.62,right7.25±1.62and B left7.00±1.65,right7.05±1.61,group C left8.05±1.82,right8.05±1.82and B, but group D left9.4±1.23，right9.4±1.23is higher than group C in the evaluation ofbilateral renal artery（p<0.05）. The evaluation of urinary system imagequality in every cases is grade I. In the measurement of CT value of theaorta, muscle, calculated enhancement of aortic and calculated CNR, groupC were309.38±70.72HU,58.60±5.33HU,261.43±74.79HU,23.12±7.98respectively, group D were493.75±65.22HU,65.75±4.12HU,428±66.15HU,29.87±6.26respectively,group D is higher than group C, the difference issignificantly（p<0.05）,but there is no significantly difference betweengroup A and B, group B and C. In the measurement of image noise, group Awere12.99±0.71,group B were11.80±1.12,roup A is higher than group B,the difference is significantly（p<0.05）; group C were11.69±2.42,groupD were14.14±0.96,roup D is higher than group C, the difference is significantly（p<0.05）; there is no significantly difference between groupB and C. Contrast dose decreased of approximately40%using0.8ml/kgthan using1.5ml/kg.Conclusion: Low contrast program can get satisfied image，and lowkV can improve the image quality of vascular in MSCT Urography as aOne-Stop Shop. PART2ASSESSMENT OF RENAL FUNCTION USING ENHANCED64-SLICE SPIRAL CTObjective: To explore the feasibility of evaluating renal function byenhanced64-Slice Spiral CT scan.Methods:150cases who took the multidetector CT Urography scanin our hospital from April2010to July2011were analyzed retrospectively.Four groups were divided: female below50group, female elder than50group, male below50group and male elder than50group. CT Values ofthe outer edge of renal cortical at the level of renal portal on both sidesduring the arterial phase were added (hereafter referred to as CT Value).The correlation of CT Values and laboratory creatinine values measured atthe same time was assessed, and the differences between CT Values of the ones with normal and increased creatinine were analyzed.Results: CT Values and ceratinine values of four groups have negativecorrelation. r-value of female below50group was-0.43(p＜0.05), r-valueof female elder than50group was-0.57(p＜0.05),the average CT Value ofnormal creatinine group was（339.5±72.6）HU, the average CT Value ofincreased creatinine group was （235.1±66.5）HU, the difference of CTValues between the normal and increased creatinine group in female wasstatistically significant(p＜0.05). r-value of male below50group was-0.53(p＜0.05), r-value of male elder than50group was-0.43(p＜0.05),the average CT Value of normal creatinine group was(314.5±59.9)HU, the average CT Value of increased creatinine group was(255.1±63.7)HU, the difference of CT Values between the normal andincreased creatinine group in male was statistically significant(p＜0.05).Conclusions: To assess renal function by measuring CT Values ofrenal cortical during the arterial phase was viable, CT Values of the renalcortex in patients with renal dysfunction during the arterial phasedecreased.