The Contrast Analysis Of Pathologic Results With Ultrasound And Radioisotope Scanning In Solitary Thyroid Nodules

BackgroundNodular thyroid disease is very common and more prevalent in women than in men.Thyroid nodules were found in 4%to 7%of the symptomatic population,in 17% to 27%of cases on ultrasonography,and in 50%to 70%of cases at autopsy.Thyroid nodules can be divided into malignant and benign according to the pathology.Benign nodules include thyroid adenoma,nodular goiter,phlogotic nodules et al.Malignant ones mainly thyroid carcinoma,fleshy tumors are rare.Refer to the clinicopathologic classification criteria raised by Hazard and Woolner,thyroid carcinoma is routinely classified into four types:papillary carcinoma,folliclar carcinoma,medullary carcinoma and anaplastic carcinoma(including squamous carcinoma).Although most thyroid nodules are benign,approximately 5%to 15%of such nodules are malignant,of which about 80%are well-differentiated ones.Some reported that solitary nodules were mostly malignant while multiple nodules were considerd to be a feature of benign lesions.But more and more research indicates that there is no difference between solitary and multiple nodules in the prevalence of carcinoma. Folliclar carcinoma is often found in multiple nodules,and 20%of papillary carcinoma is multipleceters.Surgery is applied to deal with most of thyroid solitary nodules,however is still hard to distinguish malignant nodules from benign ones.Thus to elevate preoperative diagnosis accuracy is essential for the selection of operandi modus and for prognosis.The purpose of imaging examination in thyroid is to detect lesions, discriminate malignancy in thyroid nodules and estimate the extent correctly so as to provide a guidance to choose therapeutic regimen in clinic.The diagnostic method of imaging in thyroid are mainly radionuclide image and ultrasonic imaging method.Radionuclide examination take a important place in imaging diagnosis of thyroid nodules.It was principal in diagnosing thyroid disease especially thyroid tumor. before the 20th century,70s.It assessment the character according to the biological activity and the function.of lesions.Meanwhile the thyroid morphous and texture can be displayed directly to the clinician,also make them to know the state of fuction of nodules.This method is of high sensitivity and low specificity.Ultrasonic inspection is widely used because of its non-harm,convenience,low expense and non-radioaction.With the development of high-frequency probe,color Doppler and increase of the experience of inspectors,the diagnosis of thyroid nodules has improved rapidly making ultrasonography(USG) the initial auxiliary examination of diagnosing thyroid nodules.In all imaging method of detecting throid nodules ultrasonography is the most sensitive.It can acquire lesions around 2～3mm in diameter and the detecting ratio of small lesions which are less than 2cm in diameter is higher than anyother methods.However the specificity is low respecting the complexity of ultrasonogram due to the multi-source of pathology of thyroid nodules.The current practice guidelines published by The American Thyroid Association (ATA) and The American Association of Clinical Endocrinologists(AACE) broadened the role of USG into more diagnostic fields,such as the initial screening procedure for the presence,location,and nature of the nodules,monitoring the change of size during observation,and setting the priority for aspiration among multiple thyroid nodules based on suspicious USG features.The sonographic criteria for detecting malignant thyroid nodules is still controversial at present.In this study, solitary thyroid nodules were studied with pathology as gold standard.Part one,the nodules were classified according to the separate criteria recommended by Hae Kyung and Stacul et.al of ultrasonography,and analysis the fuction of nodules assessed by radionuclide imaging to estimate the accuracy of combined ultrasound with radionuclide imaging in diagnosing solitary thyroid nodules.Part two,scored each nodule based on its ultrasonic features to evaluate the diagnosis value of ultrasonic semi-quantitive scores in thyroid nodules.Objectives1.To estimate the value of ultrasonography,radionuclide scanning,combined ultrasound with radionuclide imaging for detection of thyroid malignancy in solitary thyroid nodules.2.Evaluate the value of ultrasonic semi-quantitive scores in the differential diagnosis of solitary thyroid nodules.3.Analysis the correlation between ultrasonogram,radionuclide image and pathology.Materials and Methods1.Study objectPart one,98 patients with solitary thyroid nodules(male 27,female 71),mean age 41.8 years old.They were all underwent ultrasonography and ^99mTcO₄^- scan before operation,and confirmed by post-operation pathology.Part two,165 patients with solitary thyroid nodules(male 40,female 125),mean age 40.4 years old,all were underwent ultrasonography and finally diagnosed by pathology.2.Equipment and Method2.1 Ultrasonic inspection instrumentation is Philips IU22 and Philips HDI5000 color ultrasonoscope.The frequency of the linear array is 7～12MHz.The predetermined condition of thyroid examination was used in all patients.The patient takes supinely lie,shoulder department pad pillow,made multi-cross section scan in the thyroid.Sonograms were interpreted in term of nodular size, morphous,margin,shape,with or without a halo,echogenicity and calcification.2.2 Nuclein scanning inspection is made in GE company MG2000 SPECT with a high resolution parallel aperture collimator.An anterior static scanning was carried out 15 minutes after an intravenous injection of 185MBq(Smci) 99mTc-pertechnetate(^99mTcO₄^-).Depending on the pattern of uptake ^99mTcO₄^-,nodules are classified as nonfunctioning(cold), hypofunctioning(cool),normal functioning(warm),or hyperfunctioning(hot).2.3 Part one,the nodules were assessed based on their sonographic appearance and radionuclide image,and the results were comparatively analyzed with pathology. The three diagnostic method of ultrasonograpy,radionuclide scanning,and combined ultrasound with radionuclide imaging were compared after the sensitivity,specificity and accuracy of each method were calculated respectively.Part two,scored each nodule based on its sonographic features and compared with pathology.The receiver operator characteristic(ROC) curve was drawn according to the results.2.4 The data were analyzed by SPSS13.0,P value of less than 0.05 was considered to be statistically significant.McNemarχ² test was used to evaluate the three methods in the differentiation of solitary thyroid nodules.Wilcoxon rank sum test andχ² test was used to compare the ultrasonographic score of these benign and malignant nodules.ROC curve was drawn with sensitivity as Y-axis and 1-specificity as X-axis.Results 1.Part one,(1) The sensitivity,specificity and accuracy of ultrasonography, radionuclide scanning,and combined ultrasound with radionuclide imaging was 91.7 %,77.0%,80.6%,95.8%,37.8%,52.0%,87.5%,87.8%,87.8%,respectively; (2) There was a statistically significant difference between radionuclide scanning and combined ultrasound with radionuclide imaging(P=0.000);(3) The difference was suggested to be statistically significant between ultrasonography and combined ultrasound with radionuclide imaging(P=0.039).2.Part two,(1) Significant difference of the total scores existed between benign and malignant nodules(P=0.000).Malignant nodules got a higher score than benign ones;(2) Significant difference of the scores in each index existed between benign and malignant nodules(P＜0.01);(3) The incidence of calcification between benign and malignant nodules has a significant difference(P=0.000),but there was no significant difference between the two groups in the mode of calcification(P=0.065); (4) The area under ROC curve was 0.917.If the cut-off value of the total scores was equal or more than 4,the sensitivity,specificity and accuracy was 88.2%,94.6%, 93.3%,respectively.Conclusions1.Combined ultrasound and radionuclide was more valuable in the diagnosis of malignant nodules when compared with ultrasonography or radionuclide scanning was used alone.Both ultrasound and radionuclide scanning were effective and painless in the diagnosis of the thyroid nodule and each has its own superiority.If both methods were integrated,the accuracy will be improved.2.Ultrasonic semi-quantitive scores can improve the accuracy of diagnosis by comprehensively analyzing the sonographic features of solitary thyroid nodules.