Application Of Adaptive Statistical Iterative Reconstruction V(ASiR-V) Combining With Low-concentration Contrast And Low-output Tube Voltage In Head And Neck CTA

Part One Effect of Multi-Model Based Iterative Reconstruction(ASi R-V)Algorithm on CT Scanning Image Quality and Radiation Dose in Head and NeckObject:To investigate the change of image quality and radiation dose reduction in the head-and-neck phantom CT scan based on the pre-positioned multi-model iterative reconstruction(ASi R-V)algorithm,and to discuss a better way to optimize the image quality and radiation dose.ASi R-V weights.Materials and Method:Using human head and neck simulation model and Revolution CT machine.The head and neck body membrane was scanned with a tube voltage of 120 k Vp,automatic tube current(10 to 740 m A),a rotational speed of 0.5 s/turn,and a pitch of0.984:1.According to different pre-set ASi R-V weights(0 to 100%,interval 10%),a total of 11 groups of images were scanned;CTDIvol and DLP of each group were recorded,and the variation curve was plotted.The CT values,noise values,image subjective scores,and radiation doses of ASi R-V weights were analyzed for each group of images.Results:1.As the weight of the pre-ASi R-V gradually increases,the radiation dose gradually decreases,and the ASi R-V level is 40% to 50% in front of the ASi R-V,and the reduction rate is more significant.After 50% of the pre-ASi R-V level,the radiation dose decreases gradually.Radiation doses at 40% and 50% pre-ASi R-V were reduced by approximately 40.34% and 49.24%,respectively.2.With the gradual increase of pre-ASi R-V weights,the CT values did not change significantly and the image noise gradually increased.At 0-40% pre-ASi R-V levels,the subjective scores of the images were basically stable,and there was no significant difference in image quality.50%~100% of pre-ASi R-V levels,the subjective scores of all groups showed a gradual decrease,and the image quality gradually decreased.Conclusion Pre-ASi R-V reduces radiation dose and ensures image quality with 40% to 50%reduction in pre-level ASi R-V radiation dose significantly,with best image quality at40%.Part two Clinical application of Adaptive statistical iterative reconstruction V(ASi R-V)combining with low-concentration contrast and low-output tube voltage in head and neck CTAObjective:To evaluate the feasibility of using ASi R-V combining with low dose contrast media(245 mg I/kg)and low tube voltage(80 k Vp)(GE Revolution CT)in head and neck CT angiography(CTA).Materials and Method:Between January 2017 and June 2017,90 patients(47 males and 43 females,aged 17-75 years,mean age 59.34 � 9.53)were randomly divided into control group(group A)and experimental group(group B and C)with 30 cases in each group.The control group(group A)received iodine 315 mg I / kg,tube voltage 120 k Vp,In the experimental group B,iodine dose of 315 mg I / Kg,tube voltage of 120 k Vp,front40% ASi R-V and rear 60% ASi R-V Image reconstruction,the experimental group C with iodine 245 mg I / Kg,the tube voltage of 80 k Vp,front 40% ASi R-V scan and rear 60% ASi R-V image reconstruction,the remaining scan parameters were recorded two groups The CT values of the bifurcation of bilateral common carotid artery,1/2 of the basilar artery,and 1/2 of the horizontal part of the middle cerebral artery,and the CT value of the sternocleidomastoid muscle and diaphragm and the brain parenchyma of the same layer were used as the Bottom value,SD value as the noise value,CT volumetric dose index(CTDIvol),Dose length product(DLP),calculated according to the formula,iodine load,effective Subjective assessment of image quality(VR,MIP and CPR)by subjective scoring(5-point scale)was performed by two radiologists using blind radiotherapy(ED),contrast,CNR and SNR.Data were expressed as mean � standard deviation,chi-square test was used to compare the gender differences among groups,and the analysis of variance was used to compare the mean between groups.LSD-t test was used to compare the consistency among the two groups Kappa test was used,P<0.05 was considered statistically significant.Result:1.There was no significant difference in sex distribution between the three groups in the control group A and the experimental group B and C(?2 = 0.000,P>0.05).The age,height,weight and body mass index The difference was also not statistically significant(F= 0.473,F= 1.134,F= 0.696,F= 0.026,P>0.05,all).2.There was significant difference in CT value between head and neck in control group A and experimental group B and C(P<0.001)There were no significant differences in CT values between the two groups(all P> 0.05).There were significant differences in intra-CT values between control group A and experimental group C(all P<0.001)There were significant differences in CT values between experimental groups C(all P<0.001).3.There was no significant difference in noise among the three groups in control group A and experimental group B and C(P>0.05).4.The signal-to-noise ratio of the common carotid arteries in the control group A and experimental groups B and C were(85.59 � 29.51),(95.46 � 63.53)and(134.24� 94.59),(F= 4.296,P<0.05),the left common carotid artery was(78.32�28.96),(90.42�52.85)and(114.88�39.52),(F=6.009,P<0.05),and the basilar artery was (76.66�31.81),(61.06,respectively).(F= 10.179,P<0.001).The right middle cerebral artery were(72.57 � 26.85),(64.33 � 20.79)and(107.44 � 36.01),(F = 20.180,P<0.001).The left common carotid artery was(66.74 � 27.99),(69.58 � 30.57)and(98.86 � 27.11),respectively(F = 11.972,P<0.001).Comparing the noise of every blood vessel with each other,we found there was no significant difference between the control group A and the experimental group B(P>0.05),the difference between the control group A and the experimental group C was statistically significant(P<0.001).The difference between experimental group B and experimental group C was statistically significant(P<0.001).5.The contrast noise ratio of right common carotid artery in control group A and experimental group B and C were(74.16 � 26.92),(82.94 � 57.73)and(121.35 �88.53),(F = 4.765,P <0.05).The left common carotid artery were(68.87 � 25.48),(78.77 � 46.76)and(103.45 � 35.79)51.33�13.66)and(87.99�41.94),(F=11.410,P<0.001),right middle cerebral artery were(66.59�25.22),(58.60�19.59),and(100.63�34.66),respectively(F=21.115,P<0.001).The left middle cerebral artery were(60.68 � 25.82),(61.07 � 28.07)and(93.03 � 26.75),respectively(F = 13.918,P<0.001).Comparing the contrasting noise ratio of each blood vessel with each other,there was no significant difference between the control group A and the experimental group B(P>0.05),the difference between the control group A and the experimental group C was statistically significant(P<0.05).The difference between experimental group B and experimental group C was statistically significant(P<0.05).6.The CT volumetric index(CTDIvol)in control group A and experimental group B and C were(13.27�1.37)m Gy,(10.38�1.29)m Gy,and(4.88�0.27)m Gy,respectively(F=453.203,P<0.001).The experimental group B and C decreased by22.78% and 63.22% respectively compared with the A group,the experimental group C reduced by 52.99% and the DLP(530.10 � 65.81)m Gy-cm,(406.65�64.33)m Gy-cm and(196.25�17.08)m Gy-cm,(F=292.673,P<0.001),experimental group B and C decreased by 23.27% and 62.97%,respectively,compared with group A.The experimental group C group was lower than the experimental group B group by51.74%;effective radiation dose(ED)were(2.86 � 0.36)m Sv,(2.20 � 0.35)m Sv,and(1.05 � 0.09)m Sv,(F = 292.673,P<0.001).The experimental group B and C decreased by 23.27% and 62.97% respectively compared with the group A,and the experimental group C reduced 51.74% compared with the experimental group B.7.The iodine load in control group A and experimental group B and C were(21.26 � 2.76),(20.55 � 2.54)and(16.51 � 2.04)respectively,in control group A and experimental group B,There were significant differences between experimental group C and control group C(P <0.001).The experimental group C was 22.22%lower than the control group A and the experimental group B respectively.8.The subjective scores of the three groups in the control group A and the experimental group B and C were(4.03 � 0.669),(4.10 � 0.607)and(3.93 � 0.640)respectively,with no significant difference in subjective scores among the three groups(F = 0.517,P = 0.598,P> 0.05).Conclusion:Dual low-head technique combined with ASi R-V algorithm for CTA head and neck scanning not only reduces the patient's radiation dose and iodine dose,but also ensures the image quality to meet the diagnostic needs.