| As a major mean of examination, CT scan was widely used in almost all areas of clinical, But preoperative diagnosis of thyroid disease , particular surgical disease, has not been satisfactory. With multi-slice CT birth, the scope of application of enhancement CT by which more minute structure could be displayed has been expanded .Now, through three-dimensional CT reconstruction, we can get a comparable DSA images, while provide more information which can not be provided by DSA. All of these no doubt bring a new breakthrough to CT which rarely involved in the thyroid surgical diseases, the purpose of this paper is to approach the clinical application value of enhancement CT and three-dimensional CT reconstruction in the preoperative evaluation of thyroid surgical diseases by the retrospective study of 115 patients with thyroid diseases. research in this area has not been reported in the literature.All 115 patients in this study underwent CT enhancement scanning, 97 patients of them underwent surgical treatment, aged from 22-73 years old, average age is 47 years, 89 cases are women, 26 cases are men. All patients in This study were examined by the GE 16/64 row CT, Contrast medium was Utravist (300), which were Injected from the contra lateral elbow lesions, the injection rate was 4-4.5ml/s, All above can make constructed defect caused by the excessive concentration of the dug in the homonymy subclavian vein be avoided. while assure of the sufficient concentration of the dug in the peripheral vascular of the thyroid to make the blood vessel display more clearly. In order to maximize coverage of the possible region at which the cervical metastatic lymph node may local in the thyroid cancer. we scanned from the aortic arch to the super-mandibular angle on the level of 3-5 cm; Smart Prep technique was used in the arterial phase. The region of interest(ROI) was chosed in the level of the aortic arch. Ideal scanning results is the neck arteriovenous can be reconstructed at the same time in the arterial phase.The distribution area and the quantity of the cervical metastatic lymph node gained from the images were compared with pathological results and the ultrasonic diagnosis, In order to evaluate the application of the enhancement CT in thyroid cancer. Then the original images were analyzed by various post processing means, in order to get the most macroscopic and precise image of the relationship between the focus of infection and the blood vessel. The common post processing means: Volume Rendering (VR), Maximum intensity projection (MIP), Multiplain Reconstruction, (MPR), Curling Image, (CL), Shaded Surface Display, (SSD), Ray Sum. Then the invasion of vascular can be judged from tissue space, vascular surface, the size of the contact area between the vascular and the focus of infection, and existence of the tumor thrombus.The results of the metastatic lymph node : 71 metastatic lymph nodes were found by the MSCT, which distribute in theâ…¡-â…¦region, especially concentrationâ…¡,â…¢,â…£,â…¥four region, none in regionâ… . The sensitivity is 86.5%, consistent with the results of ultrasonic diagnosis.The results of the artery invasion: Only seven patients with artery invasion, the invasion rate is lower than that in the other parts reported in literature, 7 paitents'vessels presented in preoperative CT were involved by tumors above one-half circumference. The true positive in 6, the sensitivity of the sign was 86%, the specificity of which was 97%, p <0.01; 6 patients'vessel surface were not smooth. All of them were vascular invasion. The sensitivity of this sign was 86%, The specificity of which was 100%, p <0.01; 26 patients'tissue space disappeared, No false negative results, The sensitivity of this sign was 100%,The specificity of which was 100%, p <0.01.The results of the venous invasion: 27 cases of this group had venous invasion, 22 patients'veins involved by tumors above one-half circumference, The sensitivity of this sign was 70%,The specificity of which was 80%, p> 0.05, Lack of statistical significance. It considered that the veins'vessel wall is so tenuis that the vein was invaded before it was involved by tumors above one-half circumference; 17 patients'vein which surface were not smooth presented in MSCT were invaded, The sensitive of this sign was 63%,The specificity of which was 100%, p <0.01; 26 cases'tissue space disappeared, No false negative, The sensitivity of this sign was 96%,The specificity of which was 100%, p <0.01.The sensitive and specificity of preoperative diagnosis of the peripheral arteries invasion in the thyroid cancer was 100% and 100% respectively, while these of peripheral veins were 93% and 100% respectively.From above we can conclude that the MSCT has a high degree of sensitivity and specificity in diagnosis of neck metastatic lymph node and peripheral vessels invasion of thyroid cancer, At the same time through variety of post processing means we can rebuild the Compressed air tube in gigantic thyroid neoplasm, get a state of retrosternal thyroid, display the distribution and quantity of metastic lymph node.Compared with preoperative diagnosis of ultrasound, we found that MSCT can get a comparable ultrasonic diagnosis of metastatic lymph node; while it has superiority in diagnosis of vascular invasion to the ultrasonic diagnosis. And MSCT examination can provide more intuitive, accurate and redundant imaging information. So it is expected to replace ultrasound in preoperative assessment of thyroid cancer.In short, as a newly rising means, MSCT scan and post-processing technology have great clinical value in preoperative assessment of thyroid cancer. More intuitive, accurate imaging information provided by various reconstruction image can make fullest preoperative evaluation and preparation for the clinician, so it is worthy of promotion and application. |
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