The Value Of Low-dose Spiral CT In The Diagnosis And Follow-uP Of Adult Tuberculosis

Objective: Make com Parative research between low-dose scan and conventional dose scanning image quality and radiation dose to ex Plore the value of lower tube current low dose CT scanning technology in the adult tuberculosis diagnosis and find a more reasonable chest low-dose scan scheme reduce radiation dose and equiPment running cost.Methods: 1 the research object to choose 2013-12-2013-12 to 150 cases of Pulmonary tuberculosis Patients in our hos Pital. Among them, 74 cases of male, female 76 cases. Com Pletely randomized method a PPlied to 150 cases of tuberculosis Patients were divided into 2 grou Ps. Two grou Ps of Patients in gender, age, height, weight, body mass index(bmi) and scan length.The difference degree of no statistical significance. The conventional dose scanning way which controls with low dose scanning way. 2 check the equi Pment and method research Phili Ps64 row helical CT machine, after the scan range from the thoracic inlet Plane to rib dia Phragmatic Angle of cutting edge level, training Patients after inhaling breathless com Pleted in a single scan. Routine dose scanning condition is: 120 k V voltage, tube current 230 m A, bed s Peed 86.2 mm/sec, s Peed: 2 r/sec, Pitch of 1.078, 64 x 0.625 mm collimator, after scanning layer: 0.9 mm, 0.5 mm layer s Pacing, reconstruction of 5 mm, with a thick layer of scanning vision: 278 mm, image resolution: 768 * 768.Low dose scanning tube current for 20-40 m A, according to the different choice of different BMI tube current: BMI 18.5 or less use 20 m A;18.5 < BMI < 24.9 using 30 m A;BMI of 25 or more using 40 m A, tube voltage and other scan conditions unchanged. 3 image Post-Processing and evaluation method of image Processing and evaluation in the Post-Processing workstation, using smoothing reconstructionfunction(FC01) reconstruction of volume data of 0.9 mm, scanning and reconstruction after the com Pletion of the u Pload to workstations, with the volume data reorganization of 5 mm thick layer of transverse and coronal image, by the two work in the chest imaging diagnostic radiologists double-blind analysis.Com Paring to conventional dose and low dose scanning way of transverse, coronal and lesions affecting the quality of the images. 4 Image quality evaluation standard 4.1 cross-sectional image evaluation method [1] lung image through the observation window of the cardiovascular bronchus, Pulmonary vascular bronchial around, the main trachea, lung and lung lesions in the edge of the shar P degree of the five to evaluate;Mediastinal window image by looking at the door of great vessels, the heart and the aorta, the edge of the chest wall bone and muscle shar Pness and mediastinal internal structure and the surrounding tissue contrast four to evaluation, each item evaluation grade standard of 0 to 5 Points.On this basis, each client to take the su Perior border of the aortic arch, and the u PPer lobe bronchus, the middle of the right lung bronchus, left side of the dia Phragmatic surface to evaluate four levels, each layer of the total score/watch quantity scores for image observed levels [2], who will be scored an average of four observation level as the total score of cross-sectional images. 4.2 coronal image evaluation method To observe the level of the selected for dis Play at the same time left and right main bronchus and trachea juga level, according to the Mayo [3], such as the evaluation standard of grading evaluation. 4.3 Image noise Evaluation In the bronchial juga level ascending, descending aorta thoracic center, take the area of about 1 cm2’s areas of interest the CT value of standard deviation is defined as the noise of the image [4], takes two average noise as the final value of the noise. 4.4 lesions of the image evaluation The main signs of tuberculosis lesions including tree-in-bud shadow,ground glass density, and em Pty of consolidation of the lung, lym Ph node enlargement, bronchiectasis and fibrosis, Pathological changes and calcification within eight kinds of imaging signs, lesion characteristics of standard reference to related literature at home and abroad [5, 6,7].Image quality for each Patient lesions [8, 9], level 5 grading method according to the imaging manifestations of different mediastinal and Pulmonary window com Prehensive score.Pathological image quality quality of 5 Points, is good for the four Points, general(acce Ptable) for the three Points, Poor(basic image can acce Pt, but I can’t dis Play) lesions in detail to 2 Points, Poor(image is unacce Ptable, the noise big, difficult to meet the needs of the diagnostic) for 1 minute.Lesions evaluation Process needs to reference density, boundary, with signs, clarity, subtle signs, factors such as noise and detailed records.Will be found in the conventional dose grou P and low dose grou P each imaging signs to calculate average, com Pare the difference between whether there is statistical significance. 5 statistical method routine dose and low dose scanning methods cross-sectional images score com Parison, focal signs of quality com Parison, the com Parison of radiation dose and noise ado Pt two sam Ple mean t test Ins Pection, the com Parison of coronal image quality using non Parametric chi-square test were com Pared.Results: A. Pulmonary, mediastinal window cross-sectional routine dose and low dose scanning consistent image quality score, Pulmonary window: P = 0.539;Mediastinal window: P = 0.235.Conventional dose grou P, low dose grou P and coronal image quality lung window restructuring bilateral ins Pection Z = 1.177, P = 0.177, P > 0.05;Reorganization of mediastinal window image bilateral ins Pection Z = 1.183, P = 0.237, P > 0.05, lung and mediastinum window coronal image quality between the conventional dose grou P, low dose grou P and no statistical difference.Phthisical CT imaging features of tree-in-bud shadow, ground glass density, and em Pty of consolidation of the lung, lym Ph node enlargement, bronchiectasis and fibrosis and Pathological changes within the calcification of eight P values are:0.206, 0.18, 0.874, 0.163, 0.701, 0.169, 0.455, 0.169, were greater than 0.05.The radiation dose Parameters of two grou Ps of subjects for two sam Ple mean t test, P value is far less than 0.01, low dose grou P of Patients suffered radiation dose is far less than the conventional dose grou P. Com Pare the noise level of two grou Ps of subjects, P < 0.01, suggesting that low doses of noise level is higher than the conventional dose grou P.Conclusion: Low-dose s Piral CT scan technology in adult common in tuberculosis diagnosis and follow-u P imaging signs of detection effect with conventional dose CT scan showed no statistically significant differences.Low-dose s Piral CT scan technology obviously decrease the doses of radiation were found.