Clinical Application Of Dual - Source CT Low - Dose Technique In Delay Of Urinary

Part ⅠThe application of using CARE kV in the urinary tract imagingObjective(1) To explore the value of using intelligent optimal kV scanning technology (CARE kV) with Dual-source CT urography in reducing the radiation dose and its effect on image quality.(2) To analysis the image quality of using100kVp and80kVp tube voltage scan protocol with Dual-source CT urography and to explore the application of using100kVp and80kVp tube voltage scan protocol for reducing radiation dose.(3) To investigate the effects of Isogram Affirmed Iterative Reconstruction (SAFIRE) on application value in Dual-source CT urography comparing with regular filtered back projection (FBP).Materials and Methods(1)Collecting180cases of patients with urinary tract symptoms,with a normal BMI (male:20kg/m2≤BMI<25kg/m2,female:19kg/m2≤BMI<24kg/m2),delay scan randomly divided into6groups.Patients in group A(n=30) underwent120kV scanning with CARE kV(Off) combined CARE Dose4D techniques(Ref.mAs/rot=250).Patients in group B(n=30) underwent120kV scanning with CARE kV(semi) combined CARE Dose4D techniques(Ref. kV=120,Quality ref.mAs/rot=250).Patients in group C(n=30) underwent100kV scanning with CARE kV(semi) combined CARE Dose4D techniques(Ref.kV=120,Quality ref.mAs/rot=250).Patients in group D(n=30) underwent80kV scanning with CARE kV(semi) combined CARE Dose4D techniques(Ref.kV=120,Quality ref.mAs/rot=250).Patients in group E(n=30) underwent scanning with CARE kV(On) combined CARE Dose4D techniques(Ref. kV=120, Quality ref.mAs/rot=250). Patients in group F(n=30) underwent scanning with CARE kV(On) combined CARE Dose4D techniques (Ref.kV=100,Quality ref.mAs/rot=250).The difference between six groups in image quality, mean CT values, images noise,Contrast-to-noise ratio(CNR) and radiation dose were compared.(2)The original images of group B and C were rebuilt with SAFIRE and taken as group SAFIRE-B and SAFIRE-C. The difference between three groups in image quality, mean CT values, images noise,Contrast-to-noise ratio(CNR) and radiation dose were compared. Results(1)The mean CT value of urinary tract and psoas major in group A and B were similar, there was no statistical difference between the two groups (P>0.05).And there was no statistical difference between the image noise and CNR of group A and B(P>0.05). The mean CT value of urinary tract and psoas major in group D was higher than group B and C,which the difference was statistically significant between two groups (P<0.05).The image noise in group D was the highest,which the difference was statistically significant between three groups(P<0.05).But the CNR in group D was The minimum,which the difference was statistically significant between three groups (P<0.05).The mean CT value of urinary tract and psoas major and the image noise in group F was higher than group E,but the CNR in group E was higher than group F,The minimum,which the difference was statistically significant between two groups (P<0.05).The mean image quality scores in patients scanned with six groups were (4.86±0.21),(4.83±0.14),(4.80±0.10),(4.40±0.35),(4.77±0.23)and(4.73±0.46).The mean image quality scores in group D was slightly lower than group B and C,but there was no statistical difference between the there groups (x-=0.778,P=0.574).(2)The image noise in group B,SAFIRE-C and SAFIRE-D were(9.32±1.72),(10.13±1.77) and (10.63±1.87),there was no statistical difference between the there groups(F=1.342,P=0.325).The image noise in group SAFIRE-C and SAFIRE-D reduced about13.57%,28.32%than group C and D.The CNR in group B,SAFIRE-C and SAFIRE-D were (73.52±6.56),(72.15±6.33) and (71.59±6.21),there was no statistical difference between the there groups(F=1.673,P=0.512).There was no statistical difference between the mean image quality scores in group B,SAFIRE-C and SAFIRE-D (x2=0.743,P=0.451).(3)The effective radiation dose in six groups were (6.77±1.24)mSv,(6.52±1.13) mSv,(4.80±0.76)mSv,(2.42±0.61)mSv,(5.31±1.04)mSv and (4.03±0.73)mSv.There was no statistical difference between the group A and B(F=2.736, P=2.373).But the effective radiation dose in group D was the minimum,the difference was statistically significant(F=2.447,p=0.000).Conclusion(1)Using CARE kV(On) combined CARE Dose4D techniques with Dual-source CT urography. The scan protocol can slightly reduce radiation doses while preserve good diagnostic image quality,and the operation was simple and convenient. (2)Using low tube voltage and CARE kV(Semi) combined CARE Dose4D techniques with Dual-source CT urography.And uniting SAFIRE scan protocol.The scan protocol can substantially reduce radiation doses while preserve good diagnostic image quality. Part IIThe comparative study of different dual-source CT scan mode in the urinary tract imagingObjective(1)To compare the clinical application value of three different scan protocols for CT urological imaging, include general scanning mode, big pitch scanning mode and dual-energy scanning mode.(2)To evaluate the clinical feasibility of dual-source CT urography using dual-energy virtual non-enhanced CT.Materials and Methods(1)Collecting114cases of patients with urinary tract symptoms,with a normal BMI (male:20kg/m2<BMI<25kg/m2,female:19kg/m2<BMI<24kg/m2),delay scan randomly divided into3groups.Patients in group Ⅰ(general scanning mode,n=38) underwent120kV scanning with CARE Dose4D techniques(Ref.mAs/rot=250),screw pitch0.7.Patients in group Ⅱ(big pitch scanning mode,n=38) underwent120kV scanning with CARE Dose4D techniques(Ref.mAs/rot=250),screw pitch2.2.Patients in group Ⅲ(dual-energy scanning mode,n=38) underwent A:80kV scanning with CARE Dose4D techniques(Ref.mAs/ror=461) and B:Sn140kV scanning with CARE Dose4D techniques(Ref.mAs/rot=178),the fusion coefficient0.5,screw pitch0.7.The difference between there groups in image quality,mean CT values,images noise, Contrast-to-noise ratio(CNR) and radiation dose were compared.(2)Virtual non-enhanced CT (VNCT) image sets were reformatted in group Ⅲ from"LiverVNC".The detection rates of stone,image quality,mean CT values.images noise,Contrast-to-noise ratio(CNR) and radiation dose were compared between ture non-enhanced CT(TNCT) and VNCT image sets.Results(1)There was no statistically significant difference in the diagnostic accuracy and image quality(P>0.05).The time of the scan in group Ⅱ was significantly shorter than group Ⅰ and Ⅲ,the difference was statistically significant(F=-1.223,P=0.001). the effective radiation dose in group Ⅱ was lower than group Ⅰ and Ⅲ,the difference was statistically significant(F=2.143,2.012,P=0.001).But there was no statistical difference between the group Ⅰ and Ⅲ(F=3.6411,P=1.143).(2)There was no significant difference in mean CT numbers of all organs (P>0.05). However, VNCT images had significantly lower noise and higher CNR than TNCT images(both P<0.05). Image quality of VNCT was slightly lower than that of TNCT without significant difference (P>0.05).There were52stone in group Ⅲ,diameter range1-12mm.TNCT as the reference standard,the detection rates of stone in VNCT was94.23%(49/52).There there stones(<3mm) were not detected.Radiation dose of excretory phase scanning with dual-energy mode was higher than that of TNCT,but there was no statistical difference (F=2.711,P=0.110).Conclusion(1)A11the three groups can obtain higher diagnostic accuracy and better image quality.The big pitch scanning mode and dual-energy scanning did not increase the radiation dose. At the same time big pitch scan can effectively reduce the scanning time.(2) In dual-source CT urography, dual-energy VNCT has potential clinical values in replacing TNCT with consequent saving in radiation dose.