Dissertation
Dissertation > Medicine, health > Clinical > Diagnostics > Diagnostic Imaging > Ultrasonic diagnosis

Real-time Elastosonography in Diagnosis of Benign and Malignant Thyroid Nodules with Hashimoto Thyroiditis

Author WangJianHong
Tutor LiuShaoPing
School Shandong University
Course Medical Imaging and Nuclear Medicine
Keywords Ultrasonography Elastosonography Strain ratio Hashimoto Thyroiditis Thyroid carcinoma
CLC R445.1
Type PhD thesis
Year 2011
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Background and purposeHashimoto thyroiditis(HT), also known as chronic lymphocytic thyroiditis, was firstly described by Hashimoto in 1912. It is often associated with malignant lymphoma and occurs with papillary thyroid carcinoma (PTC). Since the first report by Daily et al in 1955, the relation between HT and PTC has been frequently discussed. It is very necessary to differential diagnosis malignant lesions with HT before surgery. Palpation is the oldest and most frequently used screening method for detecting thyroid gland tumors. One of the key features of thyroid gland cancer evaluated at palpation is the degree of firmness:Malignant lesions tend to be much harder than benign ones. Unfortunately, palpation is a highly subjective method and is dependent on the size and location of the nodule and on the skill of the practitioner and experience of the examiner. Ultrasound is the firstly chosed imaging examination. Patients with HT seem to have PTC more frequently than those without HT. It is often difficult to differentiate between benign and malignant nodules in HT because HT varies greatly on ultrasonography.US examination is a very accurate and highly sensitive method for detecting thyroid gland lesions. Two dimensional ultrasound and color Doppler ultrasound can convenienced examine the thyroid and the thyroid nodule features and blood flow. In recent years, with the development of ultrasonic instrument and ultrasonic technique, more and more new method are used in differential diagnosis of thyroid nodules. It is included of three-dimentional ultrasound, Ultrasonic contrastand and real-time elastosonography. Three-dimentional ultrasound can reconstruct two-dimentional images into three dimentional image. The use of three dimentiona ultrasound has the capability of providing real-time images of the anatomy during the procedure as well as providing three dimentional images to monitor and guide the procedure. Ultrasonic contrast can estimate the properties of disease through observing micrangium after contrast agent injected intravenously.Real-time ultrasound elastosonography is a newly developed technique that reflects US to provide an estimation of tissue stiffness by measuring the degree of distortion under the application of an external force. Elastosonography is a method that combines the detection advantages of high-frequence ultrasound with diagnostic information regarding the presence of cancer. The display presents a near-instantaneous colour "elatogram" superimposed on the B-mode imaging. On the elastogram, different colour modes imply different tissue stiffness. US elastography has been applied to study the hardness/elasticity of nodules to differentiate malignant from benign lesions.There are two real-time elastosonography estimate methods including elastic image pattern and stain ratio.we have occasionally found that a lesion was not graded consistently by different doctors who interpreted the same strain image of the lesion under the same conditions. The grade of a lesion would be biased by uncertain subjective factors. The new Strain Ratio measurement method made it possible. Waki et al found that the strain ratio was in accordance with the elasticity ratio. At present, RE is mainly used in differentiating the lesions between benign and malignant of breast, liver, and prostate.The aim of our prospective study was to investigate the role of ultrasonography in the diagnosis of PTC with HT, to investigate the diagnostic value of real-time ultrasound elastosonography in diagnosis of Hashimoto thyroiditis(HT), to evaluate the elastographic appearances of benign and malignant nodules with HT and to explore the sensitivity and specificity of real-time elastosonography for differential diagnosis benign and malignant nodules coexistent HT with histopathologic analysis as a reference standard. Objective By observing the two dimensional ultrasound and color Doppler ultrasound imaging of 39 cases of PTC with HT and 43 cases of bengin nodules with HT, to obtain the most relevant ultasonographic features of PTC with HT, to investigate the role of ultrasonography in the diagnosis of PTC with HT, in order to be helpful for early detection and treatment.Methods Selected 39 cases of PTC with HT and 43 cases of bengin nodules with HT which were confirmed by pathology after surgery or fine-needle aspiration from November 2006 and November 2009. All patients were preoperatively with two dimensional ultrasound and color Doppler ultrasound, were careful observation and recording of lesions feartures, including lesion size, border, number, echo, halo, calcification, flow classification, flow resistance index, and neck lymph node swelling, et. The ultrasonograhic appearances in PTC with Hashimoto Throiditis and bengin nodules with HT were retrospectively reviewed, to characterize the ultrasonograhic features of PTC with HT.Results It was classified into four types including unevenness pattern (14), focal hypoechoic pattern (9), asystematic hypoechoic pattern (11) and nodular pattern (5). Thirty-seven malignant nodules were diagnosed by ultrasound (78.7%,37/47), while ten ones were misdiagnosed or missed (21.3%,10/47). The diagnostic accuracy of ultrasonography was 93.1%(27/29), correlated in ultrasonography the nodules manifested as solitary in 76.9%(30/39), with metastatic cervical lymph nodes in 12.8%(5/39). Three cases were manifested solely as microcalcifications and others were irregular shaped in 77.3%, hypoechoic in 93.2%, no-halo in 70.4%, with inside microcalcifications in 56.8%, RI≥0.70 in 66.7%. Contrast to 56 benign nodules, the difference was significant in shape, edge, echo, blood flow and RI (P<0.05). There was more significant difference in irregular shapes, hypoechos and microcalcifications between the two groups (P<0.0001). The halo is not available to distinguish (P<0.05).Conclusions The ultrasonographic appearances of papillary thyroid carcinoma with Hashimoto Throiditis had some characteristics, especially hypoechoic nodules and microcalcifications. The malignant nodules in the asystematic hypoechoic pattern and nodular pattern HT are easily missed, it is necessary to confirmed by pathology after fine-needle aspiration biopsy or surgery. Objective To investigate the diagnostic value of real-time elastosonography in diagnosis of Hashimoto thyroiditis (HT).Methods One hundred and seventy-five cases clinically diagnosed as HT under went traditional ultrasound and elastosonography. The patients were classified into four types including unevenness pattern, focal hypoechoic pattern, asystematic hypoechoic pattern and nodular pattern. Thirty healthy volunteers were enrolled as control group. Thyroid elastic parameters (elastic image pattern and strain ratio) were recorded and analyzed.Results There were significant differences in elastic image pattern and strain ratio between HT and control group (P<0.05). There were significant differences in elastic image pattern between four HT groups (P<0.05).The unevenness pattern mainly had grade 0 and grade 1, focal hypoechoic pattern mainly had grade 1 and grade 2, asystematic hypoechoic pattern mainly had grade 2 and grade 3 and nodular pattern mainly had grade 3, and elastic image pattern were increased gradually from unevenness pattern to nodular pattern (P<0.05). The SR in, unevenness pattern, focal hypoechoic pattern, asystematic hypoechoic patternand nodular pattern, was 1.04±0.14,1.19±0.18,1.44±0.24,1.71±0.27, respectively. There were significant differences between four HT groups (P<0.05) in strain ratio, and were increased gradually from unevenness pattern to nodular pattern (P<0.05). Conclusions Real-time elastosonography can estimate stiffness differences between different partern HT and control group by analyzing elastic image pattern and strain ratio, is helpful for the diagnosis of HT, and superior to clinical palpation.Objective To evaluate the clinical value of elasticity grade and strain ratio using real-time elastosonography in differential diagnosis of benign and malignant thyroid nodules coexistent Hashimoto thyroiditis.Methods Elasticity imaging was used to examine 36 Hashimoto thyroiditis cases of patients with 50 nodules. The elastic image pattern and stain ratio were retrospectively reviewed and compared with pathology. The elasticity grade 0~Ⅱwas predict of benign, gradeⅢ~Ⅳwas predict of malignancy.Results 1.An elasticity grade of 0~Ⅱwas observed in 28 of 50 nodules in 36 cases, while grade ofⅢ~Ⅳin the rest of 28nodules. An elasticity grade of 0~Ⅱwas observed in 27 of 38 benign nodules, while grade ofⅢ~Ⅳin 11 of 12 malignant nodules; elasticity grade of 0-II were observed in the majority of benign nodules, while grade ofⅢ~Ⅳin the majority of malignant. sensitivity was 91.7%, specificity was 71.1% and veracity was 76.0%。2. Twelve nodules<5.03,38 nodules>5.03 in elastics stain ratio. The mean of elastics stain ratio of 7.83±4.95 in 12 malignant nodules was statistically different from that of 2.89±1.50 in 38 benign nodules (P<0.05).3. According to ROC analysis, the cut off point of stain ratio was determined as 5.03, Youden’s index was 0.67, nine HTnodules with stain ratio>5.03 were reconfirmed as malignant by pathology and 35 HT nodules with stain ratio<5.03 were reconfirmed as benign by pathology, sensitivity was 75.0%, specificity was 92.1% and veracity was 84.0%.4. The diagnostic accuracy of the stain ratio was superior to that of elasticity rade (P<0.05)Conclusions The stain ratio and elasticity grade in elasticity imagings can estimate stiffness of nodules with Hashimoto thyroiditis, can provide helper to traditional ultrasound. The stain ratio is more accurate than elasticity grade in the differential diagnosis of malignant and benign nodules with Hashimoto thyroiditis. Some malignant nodules with HT are easily missed, it is necessary to confirmed by pathology after fine-needle aspiration biopsy or surgery, and to combine with traditional ultrasound to differential diagnosis of benign and malignant nodules with Hashimoto thyroiditis using elastosonography. 1. This study was the first to describe the feature of Hashimoto thyroiditis with papillary carcinoma as being manifested solely as microcalcifications.2. This study was the first to evaluate the elastic image pattern and strain ratio of Hashimoto thyroiditis using real-time elastosonography, comparing to control group.3. This study was the first to investigate the benign and malignant nodules coexistent Hashimoto thyroiditis using real-time elastosonography, measuring the strain ratio of the thyroid parenchyma and sternocleidomastoid, and comparing the veracity between elastic image pattern and strain ratio.

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