Optimization Study Of Image Quality Of Dual-source Flash CT Dual-energy Pulmonary Angiography

With the development of hardware and software of CT, multislice spiral CTpulmonary angiography has become the preferred imageological examination forthe diagnosis of pulmonary embolism,Sensitivity and specificity were high,whichCan display the small embolus in the pulmonary trunk and its branches above thesubsegmental level,at the same time also can display the Secondary change suah aspleural effusion, pericardial effusion and pulmonary hypertension. However, somepatients are often accompanied by some complications, such as respiratory andcirculatory system disease, whose hemodynamics are poor and subjected to theinfluence of motion artifacts. the diagnosis value of CT pulmonary angiography(CTPA) is limited fot the small emboli in distal segment. On the premise of notincreasing dosage of contrast agent and radiation dose,Dual-source Flash CT dualenergy lung perfusion imaging can not only provide anatomical information ofpulmonary embolism but also evaluating lung perfusion changes that emboli caused.Dual-energy scanning mode can obtained low-energy, high-energy,and mix energyimage in one enhanced scan.The energy attenuation is different when different energyX-ray through the specific organization,which can identify the material compositionand display different organization.dual energy perfusion imaging can also provide theblood perfusion of organs according to the distribution of the iodine contrast agent indifferent organs. The purpose is to quantitativly evaluate image quality ofdual-energy different scanning mode and different monitoring level, to selectpreliminarily dual-energy scanning mode for CT pulmonary angiography(CTPA) anddual-source CT dual-energy pulmonary angiography(DEPI). Part one Comparative study of image quality of dual-energydifferent scanning mode in dual-source CT pulmonary angiographyObjective:To quantitatively evaluate the images quality CT pulmonary angiography(CTPA)and dual-source CT dual-energy pulmonary angiography(DEPI) in under low dosageof contrast agent and application value in diagnosis of pulmonary embolism ofdual-energy different scanning mode.Methods:90patients underwent dual-source CT dual-energy pulmonary angiography asthe research object,including43males and47females, age18-79years old,mean age47.2±15.1yearsold, body mass index (BMI)<30kg/m2.Records of each group of patient’s age,weight, chest diameter, body mass index (BMI).All the patients need iodine allergy test andrespiratory function training.the patients were randomly divided into three groups,group A(80/snl40kV),group B（140/80kV）and group C（100/snl40kV),The scan was initiatedwith a bolus-tracking technique,the arrival of the contrast bolus in the pulmonarytrunk was detected at a threshold of100Hounsfield Units (HU) with delay4s, thevolume of contrast agent was40ml，Contrast agent concentration of350mgI/ml。CareDose4D is adopted to reduce patients received doses of radiation.The initial data to SiemensMMWP workstation， reconstruction technology was used suan as MPR、VR、MIP and CPRfor reprocessing.The average weighted hybrid Energy data import Dual-Energy software,through the blood perfusion capacity (perfusion blood Volume, PBV) software to get doubleEnergy color-coded perfusion image.CT value of Pulmonary artery, left and right pulmonaryartery, Leaf artery,segmental artery,superior vena cava, left atrial, right room, right ventricle weremeasured.Interested area (ROI) of measurement in the original thin layer axial images, no fillingdefect in the pulmonary artery is chosen as the target blood vessels and ROI area is more than1cm2, measured three times average at the same level. pulmonary artery trunk,left and rightpulmonary artery, the back muscles of CT values were measured at the same time, the SD valueof image noise, the signal-to-noise ratio SNR and contrast to noise ratio CNR value werecalculated and record Volume CT dose index (CT dosed index Volume, CTDIvol) and dose length product (dosed length product, DLP), calculate the effective dose (effectivedose, ED), two doctorsevaluate CTPA and DEPI image quality and kappa test was used to evaluate the consistency of theevaluation results.Results:The average CT value of pulmonary trunk, Left and right pulmonary arteries,leaf artery in groups A is greater than the other two groups, statistically significantdifference between three groups was found (P＜0.05).The CT value of superior venacava in three groups has statistically significant difference（Z=5.099P＜0.05）. GroupsB is greater than the other two groups.group A and group C has no statistically significantdifference (P>0.05).segmental artery,left atrial, right room and right ventricle was no statisticallysignificant difference (P>0.05). The average CT value of segmental artery,left atrial, rightroom and right ventricle in three groups has no statistically significant difference (P＜0.05). The SD value of pulmonary trunk in groups B is greater than the other twogroups, statistically significant difference between three groups was found (Z=30.031P＜0.05).The SD value of Left and right pulmonary arteries in three groups hasstatistically significant difference (Z values were21.031,27.003, P <0.05),There was nosignificant difference for CNR values between groups(P＞0.05). Good interobserveragreement is found (Kappa=0.754, P＜0.001).Conclusion:Dual-source CT dual-energy pulmonary angiography bulb mode (80/snl40kV),the obtained image uniform perfusion, distal tiny branches showed clear, can be usedin clinical. Part two Comparative study of image quality in differentmonitoring level of dual-source CT dual-energy pulmonaryangiographyObjective:To compare image quality of dual-energy CT pulmonary angiography and lungperfusion blood volume in different monitoring level with low contrast mediavolume(40ml)Methods:60patients underwent dual-source CT dual-energy pulmonary angiography asthe research object,Patients were randomly divided into two groups and30cases ineach group.GroupA(including17males and13females, mean age50.15±13.29yearsold),GroupB(including14males and16females,mean age52.35±11.70yearsold).All the patients need iodine allergy test and respiratory functiontraining.The scan was initiated with a bolus-tracking technique,with double tube highpressure injector (Stellant) by the elbow intravenous non-ionic contrast agents beforeenhancement scan.the arrival of the contrast bolus in the pulmonary trunk group A,insuperior vena cava group B,was detected at a threshold of100Hounsfield Units (HU)with delay4s, the volume of contrast agent was40ml,the injection rate is4ml/s.Theinitial data to Siemens MMWP workstation， reconstruction technology was used suan asMPR、VR、MIP and CPR for reprocessing.The average weighted hybrid Energy data import Dual-Energy software, through the blood perfusion capacity (perfusion blood Volume, PBV) softwareto get double Energy color-coded perfusion image.CT value of Pulmonary artery, left and rightpulmonary artery, Leaf artery,segmental artery,superior vena cava, left atrial, right room, rightventricle were measured.Interested area (ROI) of measurement in the original thin layer axialimages, no filling defect in the pulmonary artery is chosen as the target blood vessels and ROIarea is more than1cm2, measured three times average at the same level. pulmonary arterytrunk,left and right pulmonary artery, the back muscles of CT values were measured at the sametime,two doctors evaluate CTPA and DEPI image quality and kappa test was used to evaluate the consistency of the evaluation results.Results:CT value of group A from pulmonary artery to the segmentpulmonary artery branches higherthan the group B, The CT value of pulmonary artery, left and right pulmonary artery and Leafartery in three groups has statistically significant difference(P＜0.05),segment Pulmonaryartery in the two groups was no statistically significant difference of CT values (t=1.037, P>1.037).. CT value of Superior vena cava CT in group A lower than group B, in the two groupsthere was no statistically significant difference of CT values (t=5.620, P>5.620). The averageCT value of left atrial, right room and right ventricle in two groups has no statisticallysignificant difference (P＜0.05).(t value were0.154,1.129,1.482, P>0.05). Two doctorsanalyze the consistency of image quality (Kappa=0.769, P <0.05).Conclusion:the artificial intelligent monitoring pulmonary artery trunk100hu delay4s withtrigger40ml contrast agent, the double energy CTA and lung perfusion images, allcan meet the requirements of disease diagnosis, can be applied to clinical.