Application Of Low-dose Computed Tomography Guided Percutaneous Lung Biopsy In Pulmonary Lesions

Objective:To evaluate the diagnostic value of CT guided percutaneous lung biopsy for pulmonary lesions and the feasibility of ultra-low radiation dose multislice spiral CT(MSCT)in CT guided percutaneous lung biopsy.Materials and Methods:The study retrospectively included 433 patients with pulmonary lesions without pulmonary puncture contraindication.All of them have difficulty in differentiation of benign and malignant lesions after conventional plain CT or even enhanced CT examination,or were needed to be histologically identified clinically.The pulmonary lesion size,puncture distance,histological type and complications were recorded.The number of patients and rate of complication were calculated.We prospectively enrolled 90 patients with pulmnary lesions,all of which unable to be differetiated benign from malignant but needed to be clinically identified.All of them have no contraindications of lung puncture.They were randomly divided into A,B,and C groups according to the radiation dose.Group A was ultra-low radiation dose group,group B was low radiation dose group,and group C was normal dose group.The scanning parameters are as follow:Group A:tube voltage 80 kV,tube current 55 mA;Group B:tube voltage 100kV,tube current55mA;Group C:tube voltage 120 kV,tube current is automatic milliamp seconds.We record or calculate the patient’s volume dose index(CTDIvol),dose length product(DLP),effective dose(ED).Two experienced doctors evaluated the image quality of puncture needle.The differences of age,DLP,ED,signal,noise,SNR and CNR among three groups were compared by ANOVA analysis and intergroup comparison.While,the difference of gender,image quality and subjective scores were compared by Kappa test.Results:All of the 433 patients successed in CT guided percutaneous lung puncture,reaching 100%.Finally,435 lesions were punctured,successful in 433 of them.The size of the lesion:118 lesions less than 2 cm,131 lesions between 2 cm to 3 cm,120lesions between 3 cm to 5 cm group,64 lesions larger than 5 cm.According to puncture distance,patients were divided into three groups:group A,less than 5 cm,253 cases(58%);group B,between 5 to 10 cm,121 cases(28%)and group C,larger than 10 cm,59 cases(14%).Of the 433 patients,only 11(2.5%)were excluded because of insuficient tissue or difficult pathological diagnosis.422(97.5%)were confirmed by biopsy,310(73.5%)malignant tumor,50(11.8%)benign lesions and62(14.7%)inflammatory disease.Among 310 malignant tumors,there were 190(61.3%)adenocarcinoma,82(26.5%)squamous cell carcinoma,18(5.8%)small cell lung cancer,12(3.9%)adenosquamous carcinoma,5(1.6%)sarcomatoid carcinoma,3(0.97%)neuroendocrine carcinoma,2(0.64%)lymphoma,1(0.32%)metastasis,and 3 other malignant tumors(0.97%),respectively.Fifty patients with benign tumors were classified as follows:28(52%)with inflammatory pseudotumor,10(20%)with hamartoma,7(14%)with sclerosing hemangioma and 5(10%)with fibroma.Of the 433 patients,75(17.3%)had puncture complications.The main complications were pneumothorax(40 cases,53.3%),hemorrhage(30 cases,40%)and hemoptysis(3 cases,4%).additionally,there were 2 cases(2.7%)with pneumothorax as well as hemorrhage.90 patients completed CT-guided percutaneous lung biopsy successfully.There are no statistically significant differences of gender,age,height,body mass index among the three groups(p value).Subjective evaluations of image quality all reach the puncture demand(more than 2 score)in the three groups,a total of 90 cases(100%).There are no significant differences in subjective score of of needle path manifestion among the three groups(X~2=2.56,p=0.235).There are no significant differences in CT value of descending aorta among the three groups.However,the SNR and CNR of ultralow dose group(group A)were lower than those of low dose group(group B)or conventional group(group C)(all p>0.05).DLP,ED and standardized ED in group A were lower compared with those in group B and C(all P<0.05),which were 44.16%,44.12%and 39.29%lower than those in group B,and78.52%,78.47%and 73.01%lower than those in group C,respectively.Conclusion:Ultra-low radiation dose CT-guided percutaneous lung biopsy can significantly reduce the radiation dose without interfering observation of needle path and puncture site.