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.
Objective To report our experience in using The Bethesda System for Reporting Thyroid Cytopathology(TBSRTC), and to investigate the diagnostic value of the system based on the cytologic-histologic result. Methods Pathological data of 2 257 thyroid nodules classified by TBSRTC which were obtained from the Department of Pathology of West China Hospital between Jan.2010 to Dec.2012 were collected and analyzed, to investigate the diagnostic evaluation indicators, such as the sensitivity, specificity, and diagnostic accuracy of the system based on the cytologic-histologic result. Results Of the 2 257 thyroid nodules, 442 (19.6%) were diagnosed as categoryⅠ, 1 184(52.4%) were diagnosed as categoryⅡ, 216(9.6%) were diagnosed as categoryⅢ, 38(1.7%) were diagnosed as categoryⅣ, 172(7.6%) were diagnosed as categoryⅤ, 205(9.1%) were diagnosed as categoryⅥ. Using TBSRTC categoryⅡas the boundary point of diagnosing benign and malignant diseases, the sensitivity, specificity, and diagnostic accuracy were 93.7%(236/252), 86.6%(323/373), and 89.4%(559/625)respectively, while categoryⅢwas excluded from analysis. When including categoryⅢinto analysis, the sensitivity, specificity, and diagnostic accuracy were 94.3%(267/283), 74.9%(323/431), and 82.6%(590/714)respectively. Conclusion The validity of TBSRTC was high at our institution. TBSRTC has proven to be an accurate and reliable approach for the diagnosis of thyroid nodules.