ABSTRACT
Objective To assess the ability of a deep machine learning technique for improving the quality of one-stop renal low dose CTP images.Methods Twenty-one cases who underwent renal noncontrast CT,triple-phase contrast enhanced CT,and CT perfusion (CTP) were collected prospectively.Revolution CT scanner was used with the scan protocol as followed:120 kVp,20 mA for CTP and 100 mA for triple-phase conctrast enhancement,axial scan,ASIR-V80％,rotation 0.5 s,coverage area for z-axial 160 mm,thickness 5 mm.A total of 15 phases were obtained for the first 28 s and then scanned once at 39,43,47,51,63,83,113,213,353,593 s for CTP,which the phases at the 22,51 and 153 s were the cortical phase,medullary phase and excretory phase,respectively.All CTP data was reconstructed with a deep machine learning technique pixel shine A7 model.The data before and after reconstruction was in group A and in group B,respectively.Compared the all data of cortex in the cortical phase and CTP parameters between the two groups.Results There were significant differences of CT values of SD of cortex (9.04 ± 1.77 and 5.75 ± 1.00,respectively),CT values of SD of elector spinae (8.52 ±2.28 and 5.67 ±0.98,respectively),CNR(16.28 ±6.61 and 28.90 ±1.50,respectively) and SNR (21.41 ± 6.67 and 30.65 ± 7.67,respectively) between the two groups (t=1.562,6.286,5.925,-5.892,-17.274,P＜0.05).The SD of images after PS-B was lower than that before PS-B significantly and SNR was improved obviously.There were no differences of cortical blood flow (BF),blood volume (BV),time to peak (TP) and medullary permeability of surface (PS) between the two groups (P ＞ 0.05).Conclusions The reconstruction of deep machine learning PixelShine technique PS-A7 can reduce the noise of images obtained with low tube current,improve the SNR and can not effect the CTP parameters.
ABSTRACT
Objective To explore the feasibility of one-stop examination with Revolution CT for axial perfusion of normal pancreas.Methods Thirteen patients who received axial perfusion scan by one-stop examination with Revolution CT were analyzed as perfusion group.Two radiologists measured pancreatic CT perfusion (CTP) parameters independently and selected optimal phase for CTA and three phases of enhanced images.The effect dose (ED) was calculated.Eighteen patients who underwent abdominal enhanced CT and CTA with spiral scan were included as control group.Patients in both groups had no pancreatic disorders.The interobserver variation of CTP parameters was estimated.Two independent radiologists separated the superior pancreaticoduodenal artery (SPDA) image into 5 points according to image quality,and the consistency was assessed.The subjective points of SPDA image quality of two groups was compared.CT value,images noise,CNR and SNR of SPDA on CTA images and those of pancreas on three phases enhanced scan images between two groups were compared.Results ICC values of all CTP parameters were higher than 0.75.The ED of perfusion protocol was (24.52±-0.01)mSv.The subjective image scores of SPDA on CTA images in both groups were both 5,the consistency was good (Kappa=0.629,0.769).The CT value,CNR,and SNR of SPDA on CTA images of CTP group were higher than those of control group (all P＜0.05).The CT value,CNR,and SNR of pancreas of CTP group were higher than those of control group in venous phase and balanced phase (all P＜0.05).Conclusion The pancreatic CT one-stop examination can be performed by Revolution CT scanner with maximum detector width with acceptable radiation dose,from which pancreatic CT perfusion data,enhanced images with high quality and better CTA images can be extracted.
ABSTRACT
Objective To explore the feasibility of axial whole-liver one-stop examination with Revolution CT.Methods Totally 19 patients were underwent upper-abdominal enhanced examination with Revolution CT and acquired whole-liver CT perfusion (CTP),vein phase and balanced phase enhanced images.Two observers recorded the rank and peak CT value corresponding to time-density curve (TDC) of abdominal aorta and portal vein respectively on the CTP images.The perfusion parameters including blood flow (BF),blood volume (BV),hepatic arterial fraction (HAF),mean transit time (MTT),time to peak (TP) of left and right liver lobe were measured.The images of hepatic artery CTA and portal vein CTV were reconstructed and the arterial phase enhanced images were extracted using the images corresponding to abdominal aorta and portal vein peak TDC.And the radiation dose of CT perfusion and one-stop examination were recorded.The differences between perfusion parameters of left and right liver lobe were compared and the consistency of two observers were analyzed.Results The differences between BV and MTT of left and right liver lobe were statistical significance (both P＜0.05).The subjective scores of hepatic artery CTA,portal vein CTV and arterial phase images were greater than 1 point.The two observers were in great consistence (Kappa＞0.6).The effective radiation dose in perfusion phase and one-stop examination were 14.47 mSv and 21.29 mSv.Conclusion With low radiation dose,Revolution CT axial wholeliver perfusion one-stop examination can provide multiple quantitative parameters of liver CTP and clear hepatic artery CTA,portal vein CTV and 3 phase enhanced scan images,which has broadly prospective in clinical application.