The Study Of Percutaneous Lung Biopsies Using An Ultra-low-dose Protocol And Study Of Low-dose Perfusion CT In Guiding Percutaneous Lung Biopsies

Part1The preliminary study of percutaneous lung biopsies using anultra-low-dose protocolObjective: To discuss the value of the dose reduction technology duringlung biopsies with an ultra–low-dose (ULD) protocol.Methods: A total of ninety consecutive patients who underwentCT-guided percutaneous lung biopsy were enrolled and randomised into ULDgroup (120kV,10mA),low dose group (120kV,50mA)and the standard dosegroup (120kV, auto-mA); There was no significant difference about lesionfeatures (size,location and the length of the needle path). Volume CT doseindex, dose length product was recorded and the effective dose was calculated.Positive rate of biopsy,the incidences of total complications,incidence ofintrapulmonary hemorrhage and the incidence of pneumothorax were alsorecorded. Radiation doses were compared by using ANOVA; Positive rate ofbiopsy and the incidences of complications were compared by usingchi-square test.Results: The effective dose were0.31±0.07mSv in ULD groups,2.69±1.34mSv in low dose group,7.29±2.71mSv in standard dose groups(F=124.16, P=3.25×10-26). The effective dose of ULD groups were11.5%,4.3%of the low dose groups and the standard dose groups. The positive rateof biopsy, the total incidences of complications,the incidence of pneumothoraxand pulmonary hemorrhage were86.7%,16.7%,13.3%and3.3%in ULDgroups,93.3%,13.3%,3.3%and10%in low dose groups,90.0%,16.7%,16.7%and0%in standard dose groups. The positive rate of biopsy(χ2=0.74,P=0.69), the accuracy in classification and grading of lung cancer(χ2=0.257, P=0.88), the incidences of total complications (χ2=0.17, P=0.92)had nosignificant difference between three groups.Conclusion: Radiation dose during CT-guided percutaneous lungbiopsies is reduced greater through the use of a ULD CT protocol withoutsignificant difference in technical success and the incidences of complicationscompared with the low dose groups and the standard dose groups. Part2The perfusion parameters of the pulmonary lumps in low doseperfusion CT with different level of ASIR and FBPObjective: The objective of this study was to compare the perfusionparameters of the pulmonary lumps reconstructed with a blend of adaptivestatistical iterative reconstruction (ASIR) and filtered back-projection (FBP).Methods: Perfusion CT were performed with a64-channelmultidetector row CT in53patients who were diagnosed with pulmonarylumps. The data were reconstructed with different reconstruction techniquesincluded20%ASIR,40%ASIR,60%ASIR,80%ASIR,100%ASIR and FBP.The slice thickness of reconstruction was5mm.The CT value of the aorta andthe noise of the images was recorded. Blood flow (BF), blood volume(BV),mean transit time (MTT) and permeability surface area product(PS) weremeasured in the lumps with the data obtained using a blend of adaptivestatistical iterative reconstruction (ASIR) and filtered back-projection (FBP).The noise of images obtained with different reconstruction techniques, the BVand BF of malignant tumors and the BV, PS and MTT of benign lesions werecompared by using ANOVA. The others were compared by usingnonparametric test.Result:The perfusion parameters of the lumps which were obtainedusing different reconstruction techniques included20%ASIR,40%ASIR,60% ASIR,80%ASIR,100%ASIR and FBP had no significant difference (P>0.05).The CT value of the aorta and the noise of the images were409.98±66.81Huand26.95±4.26in the groups using20%ASIR,414.97±67.65Hu and24.05±4.01in the groups using40%ASIR,419.43±71.45Hu and21.7±4.21inthe groups using60%ASIR,418.2±69.62Hu and19.27±3.82in the groupsusing80%ASIR,419.05±70.71Hu and16.66±4.12in the groups using100%ASIR,418.25±69.57Hu and31.61±4.42in the groups using FBP. Thedifferences were not statistically significant about the CT value of the aorta(χ2=0.4, P=0.995)and there were significant difference about the noise of theimages(F=90.106, P=1.94×10-58). The noise of the images using FBP wasgreater than using ASIR. As the rise of the level of ASIR,the noisereduced(P<0.05).Conclusion:There were not differences about the perfusion parametersof the pulmonary lumps obtained using different level of ASIR and FBP, thenoise of the images reduced using ASIR techniques. Part3The preliminary study of perfusion CT in guiding percutaneouslung biopsies using low-dose protocol and ASIR technologyObjective: To discuss the value of low dose perfusion CT in guidingpercutaneous lung biopsies using low-dose protocol and ASIR technology.Methods: A total of one hundred and twenty consecutive patients whounderwent CT-guided percutaneous lung biopsy were enrolled and randomisedinto low dose perfusion group, standard dose perfusion group, contrastenhancement group and non-contrast-enhanced CT group. There was nosignificant difference about lesion features (size, location and the length of theneedle path). Positive rate of biopsy, the accuracy in classification and gradingof lung cancer and the incidences of complications were recorded. Positive rate of biopsy, the accuracy in classification and grading of lung cancer andthe incidences of complications were compared by using chi-square test.Radiation doses between low dose perfusion group and standard doseperfusion group was compared by using independent-samples T test.Result: The positive rate of biopsy and the accuracy in classificationand grading of lung cancer were96.7%and100%in low dose perfusion group,93.3%and100%in standard dose perfusion group,93.3%and83.3%incontrast enhancement group,73.3%and75%in non-contrast-enhanced CTgroup. The differences about the positive rate of biopsy were not statisticallysignificant between the low dose perfusion group and the contrastenhancement group(χ2=0.351, P=0.554). The positive rate of biopsy of thestandard dose perfusion group was the same with that of contrast enhancementgroup. The accuracy in classification and grading of lung cancer of the lowdose perfusion group was higher than that of contrast enhancementgroup(χ2=4.537, P=0.033). The accuracy in classification and grading of lungcancer of the low dose perfusion group was the same with that of standarddose perfusion group. The positive rate of biopsy of the low dose perfusiongroup,the standard dose perfusion group and the contrast enhancement groupwere higher than that of non-contrast-enhanced CT group(P<0.05). Theincidences of total complications were10%in low dose perfusion group,20%in standard dose perfusion group,16.7%in contrast enhancement group,46.7%in non-contrast-enhanced CT group. The incidences of totalcomplications of the low dose perfusion group, the standard dose perfusiongroup and the contrast enhancement group were lower than that ofnon-contrast-enhanced CT group(P<0.05). The incidences of totalcomplications of the low dose perfusion group,the standard dose perfusiongroup and the contrast enhancement group had no significant differencebetween each other(χ2=1.184,P=0.553). The effective dose were4.25±0.72mSv in low dose perfusion group,9.94±1.93mSv in standard doseperfusion group（t=-15.101，P=2.09×10-17）.Conclusion: The application of low dose perfusion CT during lung biopsies can improve the positive rate of biopsy and the accuracy inclassification and grading of lung cancer with the reduction of incidences ofcomplications. Radiation dose during CT-guided percutaneous lung biopsies isreduced greater through the use of low dose perfusion compared with standarddose perfusion group.