The Application Value Of Multiple Detector Spiral Computed Tomography Angiography Automatic Milliampere Low Tube Voitage In The Diagnosis Of Lower Emtremity Arteriosclerosis Obliterans Disease

Objective:To evaluate multiple detector spiral CT angiography (MDCTA) automatic milliampere low tube voltage technology in the lower extremity arteriography image quality, radiation dose and diagnosis influence. Methods:Using 16 detector spiral CT to 80 cases lower extremity arteriosclerosis obliterans disease did lower abdominal aortic MDCTA inspection of arterial and MDCTA check in, all patients after two weeks adept digital subtraction angiography (DSA) examination. Will the MDCTA check 80 cases of patients were randomly divided into four groups, theⅠgroup tube voltage 100kV, noise index for 20; TheⅡgroup for tube voltage 120kV, NI for 20; TheⅢgroup for tube voltage 100kV, NI for 10 ;TheⅣgroup for tube voltage 120kV, NI of 10. Use 16 detector spiral CT scanning imaging on image quality analysis, image quality analysis quantitative index includes:artery attenuation value, image noise, background, signal-to-noise ratio (SNR) and comparative noise ratio (CNR); Original the horizontal axis of the qualitative analysis with five cents a image (not satisfied score for 1, passable for 2, basic satisfaction for 3, good for 4, excellent for 5), reconstructed adopting three cents score (rebuilding failures or lesions can't show for 1, lesions show, image quality good for 2, lesions show high quality for 3); Record comparison, the radiation dose radiation dose index includes CT volume dose index (CTDI volume), dose the product (DLP), length of effective dose (ED); For the gold standard, with DSA using sensitivity, specificity and accuracy, the positie predictie, negatie predictie five parameters to compare MDCTA diagnosis, and the difference of the degree and narrow the vascular lesions of different diameters to evaluate the diagnosis result. Statistical analysis by a single factor analysis of variance, t-test and x2 inspection,p<0.05 to have statistical differences. Results: Four groups of patients MDCTA check artery attenuation value, image noise, background have statistical differences (p<0.05), In the same NI, with decreasement of kV, CT value, noise, and background signal were all increased. However, SNR and CNR had no significant difference, and the decreasement of kV had no significant effect on them. In the same NI, there was no significant difference among the image quality of four groups, including VR and MPR. In the same kV, the image quality of two NI=10 groups is obvious bettter than the other two NI=20 groups. Four groups of X-ray radiation dose have statistical differences (p<0.05),Ⅰgroup (=20) 100kV, NI X-ray radiation dose minimum, along with the enhancement and value kV NI value X-ray radiation dose reduced significantly higher orderⅢ,ⅣgroupⅢ,Ⅰgroup, the effective dose (ED) group compared withⅣand reduce the nearly 1/2. x2 four groups of patients MDCTA tests showed that the sensitivity and specificity, check positie predictie accuracy, and no statistical difference, negatie predictie (p> 0.05). Four groups of patients with different narrow MDCTA check vascular lesions detected degree of accuracy is no statistical difference (p>0.05). Four groups of patients to MDCTA check of different diameters hemal stricture detection accuracy is no statistical difference (p>0.05). Conclusion:Multiple detector spiral CT angiography (MDCTA) automatic mA low tube voltage scanning technology significantly reduced radiation dose, ensure the quality of image at the same time, for gold standard with DSA, four groups of patients MDCTA its sensitivity and specificity, accuracy, the positie predictie, negatie predictie of different difference, not statistically different diameters and degree of narrow vascular lesions diagnosis result also without the influence, so automatic ma low tube voltage double lower limbs for clinical MDCTA should recommend routine use.