Objective To analyze the misdiagnosed cases of the nodular goiter (NG)in real-time contrast-enhanced ultrasound(CEUS),in order to improve the diagnostic accuracy of NG.Methods Two-hundred and sixty-five cases of NG CEUS images,especially the 48 nodules in 44 misdiagnosis cases,were retrospectively analyzed to find out the main reasons of the misdiagnosis.In addition,the factors which effected the results of CEUS such as size,number and calcification of NG nodules were summarized.Results There were 42 nodules misdiagnosed as thyroid cancer,5 nodules misdiagnosed as thyroid adenoma and 1 nodular goiter misdiagnosed as subacute thyroiditis in 874 nodular goiter cases.The misdiagnosis rate of nodular goiter was 5.49% (48/874)by the diagnostic criterion of homogeneous enhancement in CEUS.The differences size and calcification of nodules had a significant impact on CEUS.The misdiagnosis rate of the NG nodules with major diameter less than 10 mm was much higher than that of more than 10 mm,the misdiagnosis rate of NG nodules with coarse calcification was much higher than the situation of microcalcification(P <0.05).Conclusions Major diameter less than 10mm and coarse calcifications of NG nodular are the main factors which influence the results of CEUS.