The Value Of Multiohase Dynamic Reconstr Ucti On With Low Dose Retrospective ECG Gated To The Abdominal Aortic Dissection Intimal

ObjectiveThrough the application of retrospective ECG-gated technology combined with a variety of low dose CT technology?ECG-controlled tube current modulation and iterative reconstruction?the lower tube voltage technology?care dose technology?to discuss the value of photon low-dose CT retrospective ECG-gated technology with multiphase reconstruction dynamicl images of aortic dissection when the abdominal aorta intimal is involved.MethodsDuring December 2014-September 2015,collecting of 47 patients suspected with aortic dissection who undergone photon CT low-dose retrospective ECG-gated technology scan prospectively,among them 30 cases of patients were true aortic dissection.Then reconstruct the 30 cases of aortic dissection patients images every 5%in the cardiac cycle,from 0%to 95%R-R period reconstruct 0%?5%?10%15%……90%?95%respecti vely,20 phases images totally,the rebuilding range is from celiac axis level to renal artery.Measuring the 20 patients short axis of lumen diameter and the corresponding level diameter of abdominal aorta,in each phase at the level of CT?celiac?and SMA?superior mesenteric artery?,RRA?right renal artery?,LRA?left renal artery?,then calculate the ratio of both(d_-TL/d_-AA).Find out the d_-TL/d_-AA?true lumen/abdominal aorta?maximum,minimum,and in 70%of the R–R;After statistical test according with normal distribution,the comparison between them to test whether they have statistics difference,and statistical significance in two ratios,to judge intimal's motions indirectly.Record dose length product of every patient?dose length product,DLP?,and calculate the effective radiation dose?Effective dose,ED?.Results30 cases of patients with abdominal aortic dissection,in the four different level of CT?celiac?,SMA?superior mesenteric artery?,RRA?right renal artery?,LRA?left renal artery?,the minimum?maximum and 70%R-R phase of the d_-TL/d_-AAAA were significant ly,the intimal motion's range is wide and fast in the phase of 70%,the maximum,the minimum;in the level of CT?celiac?and SMA?superiormesenteric artery?,the maximum?minimum?70%R-R intervals of d_-TL/d_-AAAA is significantly betwe en each two ratios which means the intimal's motion is wide;in the level of RRA?right renal artery?and LRA?left renal artery?level,the maximum and the minimum of d_-TL/d_-AAAA are significant which means the intimal's motion is wide while the two others is no significant which means the intimal's motion is weak.The average DLP of this study is 1150±156.4?826¹380?mGycm,This study's effective doses of radiation is 16.1±2.19?11.6-19.3?mSv.ConclusionThe photon CT with low-dose retrospective ECG-gated technology under the condition of without increasing radiation dose companying multiphase dynamic reconstruction of abdominal aortic dissection is better than single phase image for it can be more accurate judgment and analysis abdominal aortic dissection intimal's motion...