Taewoo Kang

The Prevalence and Features of Thyroid Pyramidal Lobes as Assessed by Computed Tomography

BACKGROUND The pyramidal lobe is an accessory lobe of the thyroid gland. The prevalence of the pyramidal lobe in thyroid glands and its features have been studied in autopsy series but there is little information regarding its parameters in patients or normal subjects. The purpose of the current study was to assess the frequency, location, and size of the pyramidal lobe using computed tomography (CT) of the neck. METHODS From January to December 2010, 327 patients who underwent neck CT for trauma, thyroid cancer, pharyngolaryngeal malignancy, a palpable neck mass, cervical lymphadenopathy, and vocal cord paralysis were enrolled in the study. Their neck CTs were retrospectively analyzed by a single radiologist. Small pyramidal lobes (<9 mm) were not included in the study. RESULTS A pyramidal lobe was present in 41.3% (135/327) of the patients; some pyramidal lobes showed complete separation from the thyroid gland (12.6%, 17/135). There was no difference in the frequency of pyramidal lobe detection by gender (p>0.05, Fishers exact test). The pyramidal lobe predominantly originated from the left thyroid gland in 54.1% (73/135) of patients. There were two patients in whom the pyramidal lobe was located bilaterally (one case from both the right and left sides of the thyroid gland and one case from the left side and midline of the thyroid gland). The average length and volume of the pyramidal lobes were 25.0 mm and 129.4 mm(3), respectively. The upper margin of the pyramidal lobe was most commonly located at the level of the thyroid cartilage. CONCLUSION The prevalence of the pyramidal lobe in the left lobe of the thyroid gland is somewhat greater than 50% using the criteria employed in this study. Neck CT is useful for detecting the presence, size, configuration, and location of the pyramidal lobe.

Color Doppler Features of Solid, Round, Isoechoic Thyroid Nodules Without Malignant Sonographic Features: A Prospective Cytopathological Study

BACKGROUND No study has examined the malignancy rate and the color Doppler pattern of solid, round, isoechoic thyroid nodules (SRINs) without coexistent malignant sonographic features. We aimed to assess the cytopathological results and color Doppler patterns of SRINs through a prospectively designed study. METHODS Between January and December 2010, a total of 727 patients underwent consecutive ultrasound (US)-guided fine-needle aspirations (US-FNAs), and 27 patients who had SRINs with the largest diameter ≥5 mm at US were prospectively selected and enrolled in the study. The color Doppler pattern of each nodule was classified into one of four categories: scant, peripheral, central, or mixed type. RESULTS Out of 27 SRINs, 14 were histopathologically confirmed, and 13 were nonsurgically diagnosed by 2 consecutive US-FNAs. Among the 14 surgical SRINs, there were 7 papillary thyroid carcinomas, 2 follicular adenomas, and 5 nodular hyperplasias. All 13 nonsurgical SRINs were finally determined to be benign on the basis of results of US-FNAs and/or long-term US follow-up; thus, the malignancy rate of the SRINs was 25.9% (7/27). There was no significant correlation between the color Doppler pattern and the malignancy rate of SRINs. CONCLUSION We recommend that US-FNA should be performed for SRIN to rule out malignancy, regardless of its color Doppler pattern.

Comparative Study of Ultrasound and Computed Tomography for Incidentally Detecting Diffuse Thyroid Disease

The aim of this study was to compare the diagnostic values of thyroid ultrasound (US) and neck computed tomography (CT) in incidentally detecting diffuse thyroid disease (DTD). A single radiologist made US and CT diagnoses of incidentally detected DTD in 130 consecutive patients before thyroidectomy for various malignancies. Histopathologic examinations confirmed normal thyroid (n = 80), Hashimoto thyroiditis (n = 20), non-Hashimoto lymphocytic thyroiditis (n = 28) and diffuse hyperplasia (n = 2). Receiver operating characteristic curves revealed that the best diagnostic indices of both imaging methods were achieved on the basis of two or more abnormal imaging findings. The sensitivity, specificity and accuracy of US and CT in incidentally detecting DTD by this classification were 72% and 72%, 87.5% and 91.3% and 81.5% and 83.8%, respectively. Thyroid US and neck CT have similar diagnostic values for differentiating incidental DTD from normal thyroid.

Pre-operative Detection of Thyroid Pyramidal Lobes by Ultrasound and Computed Tomography

This study aimed to assess the diagnostic accuracy of pre-operative ultrasound (US) and computed tomography (CT) for detecting thyroid pyramidal lobe (TPL). A single radiologist prospectively performed thyroid US and retrospectively reviewed neck CT to detect TPLs in 135 consecutive patients scheduled for thyroid surgery. The location, size and superior extent of each TPL and its separation or continuity with the main thyroid gland were assessed by thyroid US, neck CT and surgery. The prevalence of TPLs as diagnosed by thyroid US, neck CT and surgery was 58.5% (79/135), 56.3% (76/135) and 60% (81/135), respectively. We compared US and CT detection of TPLs with surgical data to determine their sensitivity (85.2% and 91.4%), specificity (81.5% and 94.4%), positive (87.3% and 96.1%) and negative (78.6% and 87.9%) predictive values and accuracy (83.7% and 92.6%). For detecting TPLs, both neck CT and thyroid US have good diagnostic value, although neck CT is more accurate than thyroid US.

Sonographic Detection of Thyroid Pyramidal Lobes Before Thyroid Surgery A Prospective Single-Center Study

This study aimed to assess the rate of preoperative sonographic detection of thyroid pyramidal lobes with subsequent surgical findings as the reference standard.

Ultrasound-Based Diagnosis for Solid Thyroid Nodules with the Largest Diameter <5 mm

This study was aimed at assessing the efficacy of using an ultrasound (US)-based classification system to diagnose solid thyroid nodules with the largest diameter <5 mm (i.e., small solid nodules). For 406 small solid nodules in 365 patients who underwent thyroid US and US-guided fine-needle aspiration, each thyroid nodule was prospectively classified into one of five diagnostic categories: benign, probably benign, borderline, possibly malignant and malignant. Of 406 nodules, 145 were surgically removed: 95 papillary thyroid carcinomas, 1 follicular thyroid carcinoma, 1 poorly differentiated carcinoma, 3 pseudonodules related to thyroiditis and 45 nodular hyperplasias. On the basis of the histopathologic results, the diagnostic accuracies of US diagnosis and cytologic diagnosis were similar, but the sensitivity of US diagnosis was higher than that of cytologic diagnosis, and the specificity and positive predictive values of US diagnosis were lower those of cytologic diagnosis. An US-based classification system may be helpful for the diagnosis and management of small solid nodules.

Comparison of ultrasonography and computed tomography for diagnosing diffuse thyroid disease: a multicenter study

PurposeTo compare the diagnostic performance of ultrasonography (US) and computed tomography (CT) for diagnosing incidentally detected diffuse thyroid disease (DTD) in patients who underwent thyroid surgery using multicenter data.MethodsBetween July and December 2016, a total of 177 patients who underwent preoperative thyroid US and neck CT, and subsequent thyroid surgery at 4 participating institutions, were reviewed. US and CT images in each case were retrospectively reviewed by a radiologist at each institution, and classified into one of the following four categories based on US and CT features: no DTD; indeterminate; suspicious for DTD; and DTD. The diagnostic accuracy of US and CT were calculated at each institution by comparison with histopathological results.ResultsRespective US and CT classifications in the 177 patients were no DTD in 75 and 71, indeterminate in 46 and 34, suspicious for DTD in 28 and 31, and DTD in 28 and 41. Among the histopathological results, 113 patients had normal thyroid parenchyma, 23 had Hashimoto thyroiditis, 36 had non-Hashimoto lymphocytic thyroiditis, and 5 had diffuse hyperplasia. The presence of ≥ 2 US and CT features of DTD, which was classified as suspicious for DTD or DTD, had the largest area under the receiver operating characteristic curve (0.866 and 0.893, respectively), with sensitivity and specificity of 71.9 and 91.2% in US, and 84.4 and 84.1% in CT, respectively. However, there was no statistically significant difference between readers’ experience and their diagnostic performance.ConclusionUS and CT imaging may be helpful for detecting incidental DTD.

Utility of including BRAF mutation analysis with ultrasonographic and cytological diagnoses in ultrasonography-guided fine-needle aspiration of thyroid nodules

This study investigated the role of BRAF mutation analysis in thyroid fine-needle aspiration (FNA) samples compared to ultrasonographic and cytological diagnoses. A total 316 patients underwent ultrasonography (US)-guided FNA with BRAFV600E mutation analysis to diagnose thyroid nodules. One hundred sixteen patients with insufficient US images (n = 6), follow-up loss (n = 43), or unknown final diagnosis (n = 67) were excluded from the study. Comparisons between US diagnoses, cytological diagnoses, and BRAF mutation analysis were performed. Of 200 thyroid nodules, there was US diagnosis with 1 false negative and 11 false positive cases, cytological diagnosis with 10 false negative and 2 false positive cases, and BRAFV600E mutation analysis with 19 false negative and 2 false positive cases. The sensitivity, specificity, positive and negative predictive values, and accuracy of BRAFV600E mutation analysis were 83.2%, 98.1%, 97.5%, 86.6%, and 91%, respectively. Of the 18 nodules with Bethesda category III, 9 were true positive, 6 were true negative, 3 was a false negative, and none were false positive on BRAF mutation analysis. In conclusion, we recommend that BRAFV600E mutation analysis only be performed for evaluating thyroid nodules with Bethesda category III, regardless of US diagnosis.

Comparison of Postoperative Neck Pain and Discomfort, Swallowing Difficulty, and Voice Change After Conventional Open, Endoscopic, and Robotic Thyroidectomy: A Single-Center Cohort Study

Background: The objective of this study was to compare the postoperative neck pain and discomfort, swallowing difficulty, and voice change after conventional open thyroidectomy (COT), endoscopic thyroidectomy (ET), or robotic thyroidectomy (RT) performed by a single surgeon. Methods: From January 2013 to December 2017, 254 patients underwent COT, ET, or RT performed by a single surgeon and completed a postoperative symptom survey conducted in the outpatient clinic by three nurses. The survey collected information on postoperative neck pain and discomfort, swallowing difficulty, and voice change. Results: Of the 254 patients, 169 underwent COT, 32 underwent ET, and 53 underwent RT. The mean age in the COT, ET, and RT groups was 50.1, 44.5, and 41.6 years, respectively. The mean interval between thyroidectomy and survey in the COT, ET, and RT groups was 42.7, 50.2, and 9.2 months, respectively. Postoperative neck pain was significantly higher in the ET and RT groups than in the COT group (p = 0.026). The average neck impairment index score in the RT group was significantly higher than that in the COT group (p < 0.001). There were no significant differences in pain scale scores, swallowing difficulty, swallowing impairment index, voice change, and voice hand index among the three groups. Conclusions: There were no significant differences in postoperative voice change or swallowing difficulty among the COT, ET, and RT groups, whereas neck pain and discomfort were more common after ET and RT than COT.

SONOGRAPHIC FEATURES OF MULTIFOCAL PAPILLARY THYROID CARCINOMAS

OBJECTIVE It is uncertain whether papillary thyroid carcinomas (PTCs) of the same subtype display similar sonographic features. This retrospective analysis of pre-operative sonographic and pathologic findings aimed to assess whether PTCs of the same subtype share sonographic features. METHODS Before undergoing thyroid surgery, 137 patients underwent ultrasound (US) examination. A single radiologist used a picture archiving and communication system and pathologic reports to investigate all sonographic features of the largest and second largest PTCs. Additionally, the radiologist evaluated the similarity of sonographic features between primary (largest), secondary (second largest), and daughter (secondary with same subtype as the primary) PTCs. RESULTS Of the 137 PTC patients, 48 (35.0%) had multiple PTCs; however, 5 had no US images of the secondary PTC. Of the 43 secondary PTCs with US images, 9 (20.9%) secondary PTCs were of a different subtype than the primary PTC and revealed sonographic features that differed from those of the primary PTC. Of the 48 patients with multiple PTCs, the subtype was the same in the primary and secondary PTCs in 34 (70.8%) patients. Of the 34 daughter PTCs, 32 (94.1%) had sonographic features similar to those of the primary PTC, whereas 2 (5.9%) showed different sonographic features than the primary PTC. There was no significant difference between primary and daughter PTCs in the size, location, sonographic features, or Korean Thyroid Imaging Reporting and Data System category ( P>.05). CONCLUSION Daughter PTCs show similar sonographic features as the primary PTC. ABBREVIATIONS K-TIRADS = Korean Thyroid Imaging Reporting and Data System; PTC = papillary thyroid carcinoma; US = ultrasound.