| Background and ObjectiveThyroid nodules are exceedingly common.Well-known US is useful not only for detection but also discrimination between benign and malignant lesions,and is used as guidance for fine-needle aspiration biopsy(FNAB).In 2017,the thyroid Imaging Reporting and Data System(TI-RADS)is designed on the basis of a set of well-defined ultrasonic terminology(lexicon)by the American College of Radiology.It determines the nodule’s ACR TI-RADS level by means of giving sonographic features points,then presents recommendations bases on a nodule’s ACR TIRADS level and its maximum diameter.We wonder if it could standardize the assessment and reporting of thyroid nodules identified on sonograms like BI-RADS-US.For US to have certain level of diagnostic value,diagnostic performances and interobserver variabilities(IOVs)have to be appreciably high.According to the above may know,Radiologists play a crucial role in choosing appropriate ultrasound feature and determining whether a tissue biopsy is needed.Because US is a relatively subjective diagnostic method,observers may have different opinions when they describe and interpret lesions.Therefore,it is criticized for its possible inter-and intra-observer variations.Based on this information,Our study had four purposes: to retrospectively evaluate the interobserver variability among residents,radiologists experienced and unexperienced in thyroid imaging who used the ACR TI-RADS terminology to characterize lesions;to determine whether interobserver agreement would be enhanced at the second interpretation following a training session;to investigate how does the nodule size influences interobserver variability;to estimate their diagnostic accuracy and performance.Materials and MethodsPatientsFrom October 2012 to September 2017,more than 10,000 patients underwent thyroid US and US-guided FNAB at The First Affiliated Hospital of Zhengzhou University.All US examinations were scanned and saved(included transverse and longitudinal still imagings at least)by one professor(Dr Cui)using the i U 22 or HDI 5000(Philips Medical Systems,Bothell,WA)machine with a linear array transducer of 5–12MHz,who have more than 20 years of experience in thyroid imaging.An investigator(S.H.C.)randomly selected 300 nodules in 285 patients.The 285 patients included? women and ? men.There were 150 cases of malignancy(50%)and 150 benign nodules(50%).All malignant and 81 benign nodules were confirmed by operation.The remaining 34 benign nodules were negative for malignancy by two sessions of FNAC at a 6-month interval.Ninety-three nodules were <10mm,65 were 10–19mm,29 were 20–29mm,and 17 were ≥30mm in maximum nodule diameter.Study DesignAn investigator(Jiateng zhang)who was excluded from reviewing the images selected 2–4 representative grayscale and color Doppler images from each US examination.She converted the images into jpg files and arranged them in PowerPoint XP(Microsoft,Redmond,WA)slides in random order.Every slide contains 10 nodules pictures.A total of 30 slides were made.From 10.12-11.11,sents one slide to 20 observers by Wechat at first day without pathologic results,the next day,sent another slide and previous slide’s pathologic results,and so on.The observers includes four professional radiologists,six attending radiologists and ten junior residents form three hospitals.No clinical information about the nodules was given.To evaluate interobserver variation,the radiologists selected and recorded the descriptors and final assessments for each nodule.Agreement was analyzed by Cohen’s kappa statistic.Degree of performance was analyzed using receiver operating characteristic(ROC)curves.Differences in the areas under the ROC curves were assessed with a univariate z-score test.A p value of less than 0.05 was considered to indicate a statistically significant difference.ResultsAgreement between the experts was fair-to-good for all criteria;however,between residents,agreement was poor-to-fair.The area under the ROC curves was 0.72,0.62,and 0.60 for the experts,attending radiologists,and junior residents,respectively.There was a significant difference in performance between the experts and the residents(p < 0.05).There was a significant increase in the agreement for some criteria in the senior radiologists after the training session,but no significant increase in the junior residents.Conclusion Based on the clinical practice of ACR TIRADS,the ACR TIRADS structure is simple,easy to operate,and has a certain function of diagnosing thyroid nodules,which can be quickly mastered by primary ultrasound physicians.However,excessive diagnosis of large benign nodules is easy to be caused,and the thyroid(small)carcinoma of the cervical lymph node metastasis is missed. |
