Application Value Of Energy Spectrum Virtual Non-enhanced CT Combined With Separate Bolus Of Contrast Media Injection Of Single-phase CTU In Treating Urinary Calculi And Urinary System Diseases

Objective: To explore the application value of energy spectrum virtual non-enhanced CT(VNCT)combined with separate bolus of contrast media injection of single-phase CTU in treating urinary calculi and urinary system diseases.Methods: 42 patients with lumbago and hematuria who would undergo CT urography(CTU)were admitted prospectively and they were randomly divided into two groups according to the inclusion criteria,the experimental group and the control group.The experimental group adopted the updated CTU program which used VNCT combined with the personalized bolus of contrast media injection of single-phase energy spectrum to enhance scan,but in order to evaluate the quality of VNCT image and the detection of calculus and other lesions,routine non-enhanced CT scan of last time was used to contrast before the first separate bolus.The control group adopted the routine CTU program which used routine enhanced CT scan in the last three stages.All the scan data use the thickness of 1.25 mm,and the 80%ASIR(adaptive statistical iterative reconstruction,ASIR)to reconstruction,and then pass into the GE ADW 4.6 workstation to measure and contrast.The comparison between the experimental group and the control group were as follows.(1)CT value,noise and contrast noise ratio(CNR)between the mixing period in the experimental group and segments of collective system of the excretory phase in the control group was contrasted.(2)A contrast was made between 70 kev single energy images of the mixing period of the experimental group and the display of urinary tract anatomy structure,the evaluation of urinary tract continuity and filling on VR,MIP,CPR reconstructed images in the excretory phase of the control group.(3)Contrast the subjective evaluation of the quality of renal parenchyma image between the mixing period of the experimental group and the excretory phase of the control group.(4)Compare the detection and display of urinary system calculi and diseases between the routine CT scan and material suppressed iodine(MSI)visual non-enhanced scan in the experimental group.(5)Contrast the total average effective dose(ED)between theexperimental group and the control group and the average ED of routine non-enhanced scan and energy spectrum scan in the experimental group.(6)Contrast the total average contrast media between the experimental group and the control group.Results:(1)In terms of CT value,noise and CNR in segments of collective system,except for difference in few segments,there wasn't significant difference in most segments between the experimental group and the control group(P> 0.05).(2)There was no significant difference between the experimental group and the control group in the comparison of the the display of urinary tract anatomy structure,the evaluation of urinary tract continuity and filling(P>0.05).(3)There was no significant difference between the experimental group and the control group in the subjective evaluation of the quality of the renal parenchyma image(P> 0.05).(4)In terms of the evaluation of the detection and display of urinary system diseases and calculi,all the cases detected in the routine scan in the experimental group were all detected in the MSI virtual scan and the detection rate was 100%.46 calculi were detected via the routine scan in the experimental group and a total of 40 calculi were detected in the MSI visual scan images.By reference to the routine scan,the total check rate of MSI was about 86%.In the MSI image of calculi,the results showed that the display of tiny calculi with the longest diameter <3mm was shortened compared with that of the routine scan,and the display of tiny calculi with the longest diameter ? 3mm was consistent with that of the routine scan(Kappa value> 0.75).(5)In terms of the effective radiation dose,the average ED value of single-phase energy spectrum enhanced scan in the experimental group was 6.70 ± 1.59(mSV);the total average ED value in the control group was 30.33 ± 5.0(mSV);the average ED value of the experimental group was only about 22.09% of the control group.There was no significant statistic difference in the average ED value between the sigle-phase energy spectrum enhancement and routine scan in the the experimental group(P>0.05).(6)The total average value of the contrast media in the experimental groupwas 66.32 ml,and average value of the contrast media in the control group was 90 ml,and the average value of the contrast media in the experimental group was about73.68% of the control group.Conclusion:Energy spectrum CT VNCT and other low dosage technology combined with personalized bolus of contrast media injection of single-phase CTU in examining urinary calculi and urinary system diseases,can not only ensure the quality of the image of the patient meeting the needs of clinical diagnosis,but also greatly decrease the effective radiation dosage of the patients compared with that of routine CTU scan program which can reduce about 78% effective radiation dosage and about26% of the amount of contrast media usage,really realizing double low CTU with ultra-low radiation and low contrast media,with important clinical application value.