| Objective: To evaluate multi-slice spiral CT(multi slice spiral CT,MSCT)in different doses on display from normal scanning structure and image quality of pig lung;At the same time,the effect of different doses on the quality of the diagnostic image of lung puncture was compared,comparison of conventional dose and low dose to display the image features and image quality differences in lung lesions,thus the feasibility of multilayer spiral CT low dose chest scan and conventional clinical value the application is discussed.Methods: Take 10 cases of isolated lung specimens were inflated fresh CT scan,using conventional scanning method(current 120 m As)and low dose scanning scheme(the other scanning parameters under the same low dose,tube current was50,40,30,20,10 m As)to evaluate the quality of image after scanning the image,and the effective radiation dose for all the scan(effective dose,ED)of low dose volume CT scanning method to get the current executives.In low dose of 1mm,5mm and conventional dose 5mm cross-sectional images were reconstructed.The whole lung scanning,using the standard algorithm to reconstruct the low dose of 1mm,5mm,and conventional dose 5mm cross-sectional images,and with a high resolution algorithm,standard algorithm were reconstructed with two different doses of VR image.By referring to the needs of some patients with intravenous contrast agent after the then conventional dose(200m As)of lung Full scan.Lung scans were reconstructed using standard resolution of low dose and conventional dose 1mm cross-sectional images.After more than two evaluation of senior radiologists to all of the images are used,do not know the situation after the scanning of the evaluation results,do statistical analysis.(1)Of two doses of mediastinal window the quality of the image,lung window,shows the difference were compared.(2)Tracheobronchography: two dose and VR algorithm of SSD image quality,bronchus,bronchus display were compared.(3)To explore the quality of the lung puncture image for the clinical patients with different doses of scanning surface parameters to explore the image quality.Results:(1)Image quality: conventional dose and low-dose scan of isolated pig model obtained from the image,there is no significant difference between the segmental bronchi and lung window display image quality.Low dose effects on mediastinal window image is mainly manifested in the increase of noise,but does not affect the mediastinal window chest structure that does not affect the image observation,able to meet the diagnostic requirements.(2)Nodules or masses: no significant differences in pulmonary nodules or masses in shape and size between the whole lung images of different doses of the show,not There was no significant difference between the reconstructed images of the same dose.(3)The dose difference: compared with the conventional dose scanning,the radiation dose of low-dose scan was significantly reduced,and the statistical results showed significant difference(P<0.05).(4)Showed that different doses of 50 m As do not need to increase the effect of puncture,dose image quality can meet the requirement of diagnosis,30 m As does not need to increase the dose can meet the requirement of diagnosis,15 m As believes may need to increase the dose to meet the diagnostic requirements.Conclusion: Multi slice spiral CT low dose scanning lung specimens,the noise of image quality was significantly increased,but can be used to observe the structure of the lung;low dose scan 1mm image reconstruction algorithm,the local lesion thin axial scan with conventional dose,the use of three-dimensional VR reconstruction of the review,can accurately reflect the tumor size and morphology,pulmonary nodules and the approximate density;the tube current at 50 m As,the quality of CT image invariant and can effectively reduce the radiation dose reduction;low dose scan airway reconstruction can be used to replace the conventional dose of image reconstruction in clinical application showed airway disease. |
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