Comprehensive Evaluation Of The Clinical Course Of Hashimoto’s Thyroiditis By Ultrasonography

Hashimoto’s thyroiditis(HT)is chronic autoimmune thyroiditis,which is a primary organ autoimmune disease caused by lymphocytes attacking thyroid follicular cells.The attacked thyroid follicular cells are gradually destroyed that causes chronic inflammation and gradually enlarged volume of the thyroid gland.When the injury develops further,the content in the blood of thyroid synthetic hormone is insufficient to meet the needs of the body,and then the clinical hypothyroidism will occur.In recent years,the incidence rate of this disease was increased.The incidence rate of female was significantly higher than that of male.The disease often occurs in30-50 years old,The important factors leading to HT include genetic and environmental factors.Because of the variety clinical manifestations of HT,insidious onset,slow progress,the clinical manifestations of HT is atypical with some patients having no obvious clinical symptoms.At present,the clinical process and stage of HT are uncertain,and the ultrasonic images of HT are variable,diverse,and confusing without a unified standard category.The correlation between the types of ultrasound images and clinical progress is not clear.No comparison between ultrasound images with laboratory serological examinations has been reported in the literature.We classified the HT ultrasound images based on routine ultrasound and measured the hardness of each categorical image using ultrasonic elastic imaging,and then compared it with the laboratory serology,hoping to find out the correlation between the clinical developing procession and the ultrasound images of HT,and make a comprehensive evaluation.In this study,153 patients with HT and 50 healthy controls received routine thyroid ultrasound examine and elastography measurements.SIEMENS S3000 color Doppler ultrasound diagnostic instrument(line array probe 4L9,probe frequency 4～9MHz)and PHILIPS IU 22 color Doppler ultrasound diagnostic instrument(line array probe L12-5,probe frequency 5～12 MHz)were used.The examination contents included:two-dimensional ultrasound,color doppler flow imaging(CDFI),doppler ultrasound and ultrasonic elastic imaging.Measurements included: bilateral thyroid thickness(D),Peak systolic velocity(PSV)and end-diastolic velocity(EDV)of the superior thyroid artery,resistance index(RI),and Shear wave velocity(SWV)of thyroid tissue.According to the characteristics of HT ultrasound imaging,it could be divided into four categories in pace with the severity of inflammation and improvement of clinical procession.Nonparametric test was used to compare and analyze various categories of HT ultrasound images with laboratory serological examinations(seven items of hyperglycemia)and HT clinical progress.Virtual touch tissue imaging(VTQ)in elastography was used to analyze the shear wave velocity(SWV)changes of HT in different clinical processes.This study concluded that:1.According to the characteristics of two-dimensional ultrasound images of 153 patients with HT,their images were divided into four categories in pace with the severity of the inflammation:(1)Type I named Focal lesion included 35 cases.The volume of thyroid has normal size,and the glandular echo is similar to the normalthyroid.The lesion area is a small spot or small patchy echo reduction area.(2)Type Ⅱ named Fake nodule included 59 cases.The volume of thyroid is normal or slightly increases.The glandular echo reduces,and multiple "nodule like" echoes scatter or diffuse in the lesion area with unclear boundaries and no obvious space-occupying.(3)Type Ⅲ named Diffuse echo reduction included 27 cases.The volume of thyroid is enlarged,the lesions areas occupy the entire gland,and the glandular echo is diffusely reduced with strip-like or grid-like fiber separation.(4)Type Ⅳ named Diffuse echo enhancement included 32 cases.The volume of thyroid returns to normal or reduces.The echo of gland is enhanced,and a small number of strip-like echoes could be seen.2.Comparative analysis of HT ultrasound images and laboratory serology: TPOAb and TGAb have significant differences between type I with type Ⅱ or type Ⅲ(P<0.05),and type Ⅳ has significant differences from type Ⅱ or type Ⅲ(P<0.05).In TSH or FT4,there is a significant difference between type I or type Ⅱ with type Ⅲ or type Ⅳ(P<0.05),and a significant difference between type Ⅲ with type Ⅳ(P<0.05).3.Correlation analysis between HT ultrasound images and thyroid function: Among 153 HT patients,114 cases had normal thyroid function,and 39 cases had abnormal thyroid function.Compared the normal thyroid function with the abnormal thyroid function group,there are significant differences between the type Ⅲ images and other groups(P<0.05).In the abnormal thyroid function,9 cases had hyperthyroidism,17 cases had subclinical hypothyroidism and 13 cases had hypothyroidism.There was significant difference between hyperthyroidism type Ⅱ with type Ⅲ or type Ⅳ(P<0.05)if compared hyperthyroidism with subclinical hypothyroidism/hypothyroidism.In the subclinical hypothyroidism/hypothyroidism group,the distribution of type Ⅱ,Ⅲ and Ⅳ was found,mainly in type Ⅲ up to50%.4.Analysis of the clinical process about TPOAb,FT4 and TSH with various categories of HT: The images of 153 patients with HT were arranged in order of type I,Ⅱ,Ⅲ,and Ⅳ,and then the TPOAb,FT4 and TSH index with number of cases were selected to draw a line chart.We found that TPOAb gradually increased from normal in type I to the highest level in type Ⅱ and Ⅲ,and gradually decreased to normal level in type Ⅳ.The FT4 value is normal in type I,Short peak in type Ⅱ,gradually decreases to trough of wave in type Ⅲ,and then recovers to normal in type Ⅳ.The TSH value’s trough of wave is in type Ⅱ and Short peak in type Ⅲ.5.About the SWV:The mean SWV in the control group was 1.78±0.30m/s,with a median of 1.73m/s.The mean SWV in the HT group was2.13±0.58m/s,with a median of 2.09m/s.There was a significant difference between the control group and the HT group(P=0.000).There was significant difference between the control group with the HT group in type Ⅱ,type Ⅲ or type Ⅳ(P<0.05),and there was no significant difference with type I(P=1.000).There was a significant difference in the SWV of type I or type Ⅳ compared with type Ⅱ or type Ⅲ in the HT group(P=0.000).6.Analysis of the clinical process and various categories of HT applying VTQ: The images of 153 patients with HT were arranged in order of type I,Ⅱ,Ⅲ,and Ⅳ,and then the SWV index with number of cases were selected to draw a line chart.We found that the SWV value gradually increases in the type I image until it peaks in type Ⅱ and type Ⅲ,and then gradually decreases to type Ⅳ.In this study,153 patients with HT were observed by routine ultrasound and elastography,and the correlation between different types of HT ultrasound images with clinical process was discussed.The results show that: 1.The clinical initial stage,progressive stage,active stage and recovery stage of HT correspond to type I to type Ⅳ of ultrasound image.Hyperthyroidism generally occurs in type Ⅱ,while subclinical hypothyroidism or hypothyroidism generally occurs in type Ⅲ.2.Most HT patients have normal thyroid function.The “temporary” hyperthyroidism generally occurs in type Ⅱ while subclinical hypothyroidism or hypothyroidism generally occurs in type Ⅲ.3.The thyroid tissue hardness changed with the HT clinical process.The tissue hardness value was thelargest while the inflammation of HT was most severe in type Ⅱ or Ⅲ,and was decreased with the regression of inflammation in type Ⅳ.