Low Dose Scan Of320Slice Combined With Low Concentrations Of Contrast Agent In The Lower Extremity In CTA

Objective:To evaluate the application value of320slice CT in the double lowerlimb vascular disease, by reducing radiation dose and low concentrationsof contrast agent, compared with previous normal dose and highconcentration of contrast agent by angiography, CT value, the detectionrate of vessel definition and lower extremity vascular disease, todetermine the feasibility of low dose scanning.Methods:In December201103-201206to vascular disease in patients treatedin our hospital30patients divided into three groups (A, B, C), A groupfor the conventional group, with iodine contrast agent Omnipaque350,conventional scanning dose120KV, without iterative reconstructiontechnique and automatic mA; group B as the control group, withOmnipaque350, reduce the dose to scan80KV, the applicationautomatically mA and iterative reconstruction technique; group C is alsoa control group, with low concentrations of the contrast agent Visipaque270, scanning dose of80KV, the application automatically mA anditerative reconstruction technique. Three methods of scanning the imagequality lower extremity vascular imaging were compared by the two senior titles diagnostician double-blind method. Compare the signal tonoise ratio, resolution and lower extremity vascular lesion detection ratedifferences. Using SPSS16.0statistical package for each set of data forstatistical inference, technical data using the chi-square Fisher exact test.Test level of0.05, if P <0.05, the difference was considered statisticallysignificant.Results:By comparing the three groups of image quality analysis, A, B, Cthree groups of volume CT dose index (CTDIvol) were5.40mGy,2.91mGy,2.59mGy.B group than in A group decreased by46%, C groupthan in A group decreased by52%. A, B, C three groups showed nostatistical significance of vascular SNR.The three groups had statisticalsignificance in different segments of soft tissue SNR, the dose reductionwill affect the soft tissue imaging. Quality evaluation of A, B, C threegroups of images of2physicians subjective evaluation, results were notstatistically significant, and no one case.(chi square values were4.032,5.163,2.030, P>0.05).2physicians to assess CTA image with ahigh degree of consistency (kappa values greater than0.75, P <0.05).Conclusion:Iterative reconstruction technique, low tube voltage with lowconcentrations of contrast agent in the lower extremity in the application of CTAin ensuring the image quality, radiation dose was decreased, so thelow dose scan will become the inevitable trend of CT scanning.