Objective To summarize the basic principle of electrical impedance spectrum technology and the latest progress in the diagnosis of thyroid carcinoma. Methods By the domestic and overseas literatures review， medical application and diagnostic prospect in thyroid carcinoma of electrical impedance spectrum were summarized. Results Electrical impedance spectrum was a kind of somatic function imaging， whose measurement results was objective， and it could diagnose thyroid carcinoma in early stage effectively. In addition， it could be used as a complementary form of fine needle aspiration biopsy， improving the diagnostic accuracy rate of thyroid carcinoma， thereby reducing the unessential thyroid operations. Conclusion Electrical impedance spectrum technology is a potentially useful imaging modality for diagnosing thyroid carcinoma in early stage， and functions as a auxiliary clinical diagnosis method for fine needle aspiration biopsy.
ObjectiveTo assess the effect of the size of thyroid nodules on the diagnostic rate of ultrasound guided aspiration cytology (US-FNAB). MethodsThe data of 1 142 (performed by two doctors, 571 each) thyroid nodules between March 2011 and April 2014 in our hospital were retrospectively analyzed. Yields of US-FNAB were divided into two levels of adequacy and inadequacy according to the classification standard of the Bethesda system. The thyroid nodules were classified into five groups according to the largest diameter:≤5 mm group, 5-10 mm group,10-20 mm group, 20-30 mm group, and <30 mm group. According to the grouping of the nodules and the efficiency of US-FNAB drawed curve, the adequacy rates of alone and total of two examiners in each group were analyzed, respectively. ResultsThe adequacy rates of US-FNAB of alone and total of two examiners in≤5 mm group, 5-10 mm group,10-20 mm group, 20-30 mm group, and <30 mm group was 68.42%, 83.72%, 86.08%, 84.62%, and 73.53% (examiner 1); 68.75%, 70.53%, 81.05%, 86.15%, and 73.91% (examiner 2); 68.59%, 77.53%, 83.59%, 85.47%, and 73.75% (total of two examiners), respectively. The total adequacy rate of US-FNAB of two examiners in≤5 mm group was lower than that in 10-20 mm group (P<0.001) and 20-30 mm group (P=0.001). The adequacy rate of US-FNAB of examiner 1 in 5-10 mm group was higher than that examiner 2 (P=0.001). ConclusionsThe size of thyroid nodules significantly influences the adequate diagnostic rate of US-FNAB. The adequacy rates of US-FNAB of the largest diameter≤5 mm or <3mm were lower. The low adequacy rate of US-FNAB may be associated with cystic degeneration in the larger nodules.