Impact of Respiratory Phase during Pleural Puncture on Complications in CT-Guided Percutaneous Lung Biopsy.

Purpose: This study investigated whether the respiratory phase during pleural puncture in CT-guided percutaneous transthoracic needle biopsy (PTNB) affects complications. Materials and Methods: We conducted a retrospective review of 477 lung biopsy CT scans performed during free breathing. The respiratory phases during pleural puncture were determined based on the table position of the targeted nodule using CT scans obtained during free breathing. We compared the rates of complications among the inspiratory, mid-, and expiratory respiratory phases. Logistic regression analysis was performed to control confounding factors associated with pneumothorax. Results: Among the 477 procedures, pleural puncture was performed during the expiratory phase in 227 (47.6%), during the mid-phase in 108 (22.6%), and during the inspiratory phase in 142 (29.8%). The incidence of pneumothorax was significantly lower in the expiratory puncture group (40/227, 17.6%; p = 0.035) and significantly higher in the mid-phase puncture group (31/108, 28.7%; p = 0.048). After controlling for confounding factors, expiratory-phase puncture was found to be an independent protective factor against pneumothorax (odds ratio = 0.571; 95% confidence interval = 0.360-0.906; p = 0.017). Conclusion: Our findings suggest that pleural puncture during the expiratory phase may reduce the risk of pneumothorax during image guided PTNB.

Effect of the respiratory motion of pulmonary nodules on CT-guided percutaneous transthoracic needle biopsy.

BACKGROUND: Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is highly affected by respiratory motion; however, respiratory motion of target nodule during the PTNB and its effect on CT-guided lung biopsy have not been studied. PURPOSE: To investigate the effect of the respiratory motion of pulmonary nodules on CT-guided PTNB. MATERIAL AND METHODS: We retrospectively reviewed the procedural CT scans of 426 pulmonary nodules that underwent PTNB during quiet breathing. Maximal and average respiratory motions were measured using the difference of table position of the targeted nodule between multiple procedural scans. Diagnostic performance, complications, and technical factors of PTNB in nodules with large motion (maximal motion >1 cm) were compared with those in nodules with small motion (≤1 cm). RESULTS: The mean maximal and average respiratory motions between tidal volume breathing were 5.4 ± 4.4 and 2.7 ± 2.6 mm, respectively. Sensitivity and accuracy were 93.1% and 96.1% in nodules with large motion, compared with 94.7% and 95.9% in nodules with small motion, respectively. Respiratory targeting (P < 0.001), needle modulation (P < 0.001), motion artifact of target (P < 0.001), target disappearance from scans (P < 0.001), and number of performed CT scans (P < 0.001) were significantly higher in the large motion group, with no significant difference in radiation dose and complications between the groups. CONCLUSION: The respiratory motion of pulmonary nodules during CT-guided PTNB may cause technical difficulties but does not affect diagnostic performance nor complications associated with PTNB.

Isolated Intracranial Rosai-Dorfman Disease Mimicking Meningioma: A Case Report.

Rosai-Dorfman Disease (RDD) is a rare lymphoproliferative disease, and the occurrence of isolated intracranial RDD is extremely rare. Most cases of intracranial RDDs present as dural masses showing homogenous enhancement on MRI, which makes it difficult to differentiate these masses from meningiomas before surgery unless massive cervical lymphadenopathy is observed. We herein report a rare case of isolated intracranial RDD in a 65-year-old male. Brain MRI revealed a well-defined enhancing mass-like lesion involving the right frontal convexity and subtle diffusion restriction. However, only a subtle blush was observed on the preoperative cerebral angiogram. Although instances of isolated intracranial RDD are rare, it should be considered as a potential differential diagnosis when a dural mass with hypovascularity is visualized on the cerebral angiogram.

Is Free Breathing Possible During Computed Tomography-Guided Percutaneous Transthoracic Lung Biopsy? The Clinical Experience in 585 Cases.

OBJECTIVE: The aim of the study was to retrospectively evaluate the safety and accuracy of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions during quiet breathing. METHODS: We investigated the diagnostic performance and complication rate of 585 procedures in 563 patients (357 men; mean age, 67.7 years), who underwent CT-guided PTNBs during quiet breathing, aided by a respiratory targeting technique from May 2017 to July 2019. Differences between the cases with and without respiratory targeting were analyzed. Logistic regression analyses were performed to examine the development of pneumothorax and hemoptysis. RESULTS: Percutaneous transthoracic needle biopsy samples were successfully obtained in 574 of 585 procedures (98.1%). Final diagnoses included: 410 malignant cases, 119 benign cases, and 45 indeterminate cases. The sensitivity, specificity, and accuracy of diagnosis were 94.4%, 100%, and 95.7%, respectively. Use of respiratory targeting was associated with younger age (P = 0.004), smaller lesion size (P < 0.001), peripheral location (P = 0.003), shorter distance from the diaphragm (P < 0.001), lower lobe location (P < 0.001), prone position (P = 0.004), and visible motion artifact (P < 0.001). Pneumothorax and hemoptysis rates were 22.9% and 7.9%, respectively. Upon multivariate analysis, emphysema (P = 0.002) was the only independent risk factor for pneumothorax, whereas distance from the pleura greater than 2 cm (P < 0.001), tissue sampling 3 times or more (P = 0.003), and a less experienced operator (P < 0.001) were risk factors for hemoptysis. CONCLUSIONS: Computed tomography-guided PTNB during quiet breathing with respiratory targeting yielded high diagnostic performance with a slightly higher rate of complications. Free-breathing PTNB can be applied in clinical practice, based on lesion location and risk factors for complications.

Detection of pericardial flow in black blood-prepared T2 HASTE sequence imaging: Differentiation between pericardial diverticulum and cyst.

Pericardial diverticulum is a focal herniation of the pericardium. It is differentiated from a pericardial cyst by the presence of communication with the pericardial cavity. Radiological differentiation between the diverticulum and cyst via computed tomography is difficult unless changes in size are identified with different body positions in additional scans. Herein we describe a case of pericardial diverticulum that was successfully diagnosed via the detection of internal pericardial flow in black blood-prepared T2 half-Fourier acquisition single-shot turbo spin-echo magnetic resonance imaging. Detection of a flow void in the pericardial sac may be a definitive magnetic resonance imaging finding in the diagnosis of pericardial diverticulum.

Bilateral Triple Negative Invasive Ductal Breast Carcinoma in a BRCA1 Mutation Carrier with Discrepant Pathologic Response to Neoadjuvant Chemotherapy.

Herein, we report a case of synchronous bilateral triple negative invasive ductal breast carcinoma in a patient with discrepant pathologic response to neoadjuvant chemotherapy. Right and left breast cancer stages at the initial diagnosis were T1cN0M0 and T4dN3aM0, respectively. The patient was identified as a BRCA1 mutation carrier and treated with four cycles of adriamycin and cyclophosphamide, followed by four cycles of docetaxel. Bilateral breast cancer stages decreased with the first regimen. However, the bilateral breast cancers showed discrepant responses to chemotherapy with docetaxel. The right breast cancer showed a continuous tumor volume reduction while the left breast cancer showed marked progression. Finally, the tumor size was 0.3 cm and 12 cm in the right and left mastectomy specimens, respectively. As bilateral breast cancers of the same subtype may show discrepant responses to neoadjuvant chemotherapy, close monitoring and follow-up imaging are required to avoid delayed surgery.

Erratum: Bilateral Triple Negative Invasive Ductal Breast Carcinoma in a BRCA1 Mutation Carrier with Discrepant Pathologic Response to Neoadjuvant Chemotherapy.

[This corrects the article on p. 428 in vol. 81.].

Significance of baseline computed tomography assessment for predicting the pulmonary fibrosis during the course of chemotherapy-induced pneumonitis.

BACKGROUND: The purpose of our study is to evaluate risk factors for the development of pulmonary fibrosis in the baseline computed tomography (CT) during the course of chemotherapy-induced pneumonitis (CIP). METHODS: We retrospectively identified 80 cases of CIP by clinical, radiological, and pathological findings. When fibrosis developed during the follow-up, the extent of pulmonary fibrosis was evaluated at final follow-up CT in terms of a 5% volumetric score for six zones. Univariate and multivariate analyses were performed to identify the clinical and radiological risk factors for the development of fibrosis and severe fibrosis over 11% in extent. RESULTS: Fibrosis occurred in 26 of the 80 total patients (32.5%) during a mean 5.6 months of follow up. Risk factors for developing fibrosis were revealed as preexisting interstitial lung disease (ILD) and moderate to severe emphysema in multivariate analysis (OR = 10.12, 95% CI = 2.35-43.66, and OR = 12.85, 95% CI = 2.81-58.82, respectively). Risk factors for developing severe fibrosis over 11% in extent were revealed as a moderate to severe emphysema (OR = 5.78, 95% CI = 1.07-31.26) in multivariate analysis. CONCLUSIONS: Moderate to severe emphysema as well as preexisting ILD visible on baseline CT are risk factors for developing pulmonary fibrosis in the course of CIP. Thin-section CT may be helpful to predict the risk of pulmonary fibrosis before administering chemotherapy.

Unexpected Lung and Brain Metastases 9 Years After Thyroid Lobectomy for Follicular Adenoma: A Case Report.

Background: Benign thyroid follicular tumors without histological evidence of carcinoma can metastasize. However, the pathogenesis of metastasis remains unclear. Here, the new proposed terminology, "non-invasive follicular thyroid neoplasm with papillary-like nuclear features" should be considered. We present a case of an encapsulated type of follicular variant of papillary thyroid carcinoma (FVPTC) that exhibited distant lung and brain metastases and was initially diagnosed as follicular adenoma. Case Report: In December 2006, a 64-year-old woman underwent ultrasonography-guided fine-needle aspiration of the right thyroid nodule at our hospital because of a palpable right neck mass. Right lobectomy was performed, and a follicular adenoma was diagnosed. In October 2015, she visited our hospital owing to dry cough and mild dyspnea and underwent computed tomography-guided transthoracic core needle biopsy for the lung nodule owing to probably multiple lung metastasis on chest X-ray and computed tomography. Based on retrospective analysis of the primary thyroid tumor and lung nodule specimen, an encapsulated follicular variant of papillary thyroid carcinoma with lung metastasis was confirmed. Conclusion: We report a case of an encapsulated follicular variant of papillary thyroid carcinoma with unexpected metastasis to the lung 9 years after thyroid surgery in a patient who was initially diagnosed as follicular adenoma. A careful close follow-up with re-examination of the histopathology specimen may be needed in patients who were diagnosed with benign thyroid follicular tumors.

Comparison of cytological adequacy and pain scale score in ultrasound-guided fine-needle aspiration of solid thyroid nodules for liquid-based cytology with with 23- and 25-gauge needles: a single-center prospective study.

In ultrasound (US)-guided fine-needle aspiration (FNA) of solid thyroid nodules (STN) using liquid-based cytology (LBC), the most appropriate needle size for LBC remains unclear. This study compared the cytological adequacy and complications associated with using 23- and 25-gauge needles in US-guided FNA of STNs using LBC. US-guided FNA was performed in consecutive patients by one radiologist to diagnose STNs ≥ 5 mm in the largest diameter. The one-sampling technique through a single needle puncture and multiple to-and-fro needle motions was used in each patient. The 23- and 25-guage needles were used consecutively each day. After FNA, the pain and complications experienced by each patient were investigated by a nurse, who was blinded to the information of needle gauge used. A cytopathologist retrospectively analyzed the cytological adequacy and cellularity of the cases. Of the 99 STNs, eight (8.1%) exhibited inadequate cytology (4 each with 23- and 25-gauge needles). The rate of cytological adequacy was not statistically different between the groups (p = 0.631). The mean pain scale values with 23- and 25-gauge needles were 2.1 ± 1.3 and 1.6 ± 1.3, respectively (p = 0.135). There were no significant complications in either group. In conclusion, both 23- and 25-gauge needles are useful in LBC because cytological adequacy and complications were not statistically different with both sizes of the needles.

Dual-energy CT angiography-derived virtual non-contrast images for follow-up of patients with surgically clipped aneurysms: a retrospective study.

PURPOSE: To evaluate the diagnostic performance, image quality, artifacts, and radiation doses of virtual non-contrast (VNC) images, relative to true non-contrast (TNC) images, in patients with surgically clipped aneurysms. METHODS: Seventy-six patients who underwent unenhanced computed tomography (CT) and dual-energy (DE)-CT angiography after surgical clipping of 85 intracranial aneurysms were included in the study. Diagnostic performances of VNC and TNC images were compared with respect to sensitivity, specificity, and positive and negative predictive values. The results of quantitative and qualitative analyses were compared between VNC and TNC images. Radiation doses were also compared between VNC and TNC images. RESULTS: Diagnostic performance of VNC images was lower than that of TNC images; however, addition of contrast-enhanced images improved diagnostic performance. Image noise and mean attenuation of VNC images were significantly higher than those of TNC images in the centrum semiovale, cerebellum, and pons. The quality of VNC images was excellent or sufficient (85.5% for observer 1, 85.5% for observer 2), and complete acceptance of VNC images was achieved in 64.5% for observer 1 and in 71.0% for observer 2; however, the addition of contrast-enhanced images increased the level of acceptance (92.0% for observer 1, 90.9% for observer 2). Clip artifacts were significantly lower in VNC images than in TNC images. CT dose index, dose-length product, and effective dose were significantly lower without TNC images. CONCLUSION: VNC images showed lower diagnostic performance and image quality, and higher image noise than TNC images; however, VNC images could reduce clip artifacts and radiation doses.

Causes of early rebleeding after coil embolization of ruptured cerebral aneurysms.

OBJECTIVE: Early rebleeding after coil embolization of a ruptured cerebral aneurysm is rare but may cause severe disability or death. We present a case series of early rebleeding after coil embolization of ruptured cerebral aneurysms and investigate the incidence, clinical outcome and possible mechanism through retrospective analysis of angiographic and surgical findings. PATIENTS AND METHODS: This study included 347 consecutive patients who had undergone successful coil embolization of 347 ruptured cerebral saccular aneurysms. Clinical and angiographic data and findings from emergent surgery were analyzed retrospectively. RESULTS: Early rebleeding occurred in eight aneurysms (2.3%) and was especially frequent among anterior communicating artery lesions (6 out of 122, 4.9%). The other two events involved posterior communication artery lesions. The maximum diameter of the aneurysms that developed early rebleeding was 4.89 ± 0.65 mm, ranging from 3.9 to 5.7 mm. In seven out of eight patients, the immediate radiologically determined occlusion status was a residual neck, and the remaining patient had a residual sac. The coil packing density was between 21% and 34%. Six cases of rebleeding were detected within 48 h, 1 case was detected on the 5th day, and 1 case was detected on the 10th day. Coil compaction was not detected by follow-up angiography after early rebleeding. We performed surgical clipping as a rescue procedure in 5 cases and additional coil embolization in 1 case. During follow-up angiography and rescue clipping, inflow of blood to the aneurysm was detected in 6 cases. Three patients died, and the other 3 patients were severely disabled. The mechanisms of early rebleeding were divided into two types. First, blood may flow into the rupture site through a gap between the coil mesh and the aneurysm neck. Second, blood may enter the rupture site through the coil mesh due to insufficient thrombus formation. CONCLUSIONS: The early rebleeding rate after coil embolization of ruptured cerebral aneurysms in our study was 2.3%. The ruptured aneurysms were small in size (<6 mm), and rupture frequently occurred in the anterior communicating artery. In most cases, inflow of blood to the aneurysm was detected by follow-up angiography or during rescue surgery.

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.

Ultrasonographic Features of Papillary Thyroid Carcinomas According to Their Subtypes.

BACKGROUND: The ultrasonographic characteristics and difference for various subtypes of papillary thyroid carcinoma (PTC) are still unclear. The aim of this study was to compare the ultrasonographic features of PTC according to its subtype in patients undergoing thyroid surgery. METHODS: In total, 140 patients who underwent preoperative thyroid ultrasonography (US) and thyroid surgery between January 2016 and December 2016 were included. The ultrasonographic features and the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) category of each thyroid nodule were retrospectively evaluated by a single radiologist, and differences in ultrasonographic features according to the PTC subtype were assessed. RESULTS: According to histopathological analyses, there were 97 classic PTCs (62.2%), 34 follicular variants (21.8%), 5 tall cell variants (3.2%), 2 oncocytic variants (1.3%), 1 Warthin-like variant (0.6%), and 1 diffuse sclerosing variant (0.6%). Most PTCs were classified under K-TIRADS category 5. Among the ultrasonographic features, the nodule margin and the presence of calcification were significantly different among the PTC subtypes. A spiculated/microlobulated margin was the most common type of margin, regardless of the PTC subtype. In particular, all tall cell variants exhibited a spiculated/microlobulated margin. The classic PTC group exhibited the highest prevalence of intranodular calcification, with microcalcification being the most common. The prevalence of multiplicity and nodal metastasis was high in the tall cell variant group. CONCLUSION: The majority of PTCs in the present study belonged to K-TIRADS category 5, regardless of the subtype. Our findings suggest that ultrasonographic features are not useful for distinguishing PTC subtypes.

Utility of routine ultrasonography follow-up after total thyroidectomy in patients with papillary thyroid carcinoma: a single-center study.

BACKGROUND: This study aimed to assess the appropriate number of sessions and interval of routine follow-up ultrasonography (US) in patients who underwent total thyroidectomy for papillary thyroid carcinoma (PTC). METHODS: Between January 2008 and December 2009, 569 patients underwent total thyroidectomy for PTC. Of the 569 patients, 44 were excluded from the study because of no US follow-up data for the neck (n = 43) or owing to indeterminate tumor recurrence/persistence (n = 1). The follow-up US for all the patients was performed by a single radiologist. Based on the cytohistopathological results, tumor recurrence/persistence was determined. RESULTS: In the 525 patients, the mean interval to the last follow-up US was 54.7 months, and the mean number of follow-up US sessions was 4.4. Of the 525 patients, 31 (5.9%) showed nodal (n = 30) and non-nodal (n = 1) tumor recurrence/persistence. Patient age and N stage were independently associated with tumor recurrence/persistence. Among patients showing tumor recurrence/persistence after total thyroidectomy, the time at first detection of suspicious US findings on follow-up US was ≤8 months in 2 patients, between 10 and 23 months in 21, and ≥ 25 months in 8. In a receiver operating characteristic curve analysis, the number of sessions and interval of the provided follow-up US were inappropriate for the detection of tumor recurrence/persistence. CONCLUSIONS: For the detection of tumor recurrence/persistence after total thyroidectomy in PTC patients, routine US follow-up with a 1- or 2-year interval may be excessive.

Appropriate Frequency and Interval of Neck Ultrasonography Surveillance during the First 10 Years after Total Thyroidectomy in Patients with Papillary Thyroid Carcinoma.

BACKGROUND: No previous study has employed the frequency and interval of follow-up ultrasonography (US) during the first 10 years after total thyroidectomy in patients with papillary thyroid carcinoma (PTC). The aim of this study was to determine the appropriate frequency and interval of follow-up US during the first 10 years in patients who have undergone total thyroidectomy for PTC. METHODS: Two hundred seventy-two patients underwent total thyroidectomy for PTC at our institution from January 2006 to December 2007. Nineteen patients were excluded because of lack of US follow-up data for the neck. Follow-up US was performed by one of two radiologists in all patients. Tumor recurrence/persistence was confirmed by histopathology. RESULTS: The mean interval between surgery and the final follow-up US examination was 79.0 months, and the mean number of follow-up US sessions was 5.9 in the 253 evaluable patients. Eleven patients (4.3%) developed tumor recurrence/persistence, which was detected on follow-up US within 5 years after total thyroidectomy in all cases. T and N stages were independently associated with tumor recurrence/persistence. The interval between surgery and first suspicion of tumor recurrence/persistence on follow-up US was ≤12 months in six patients and 20, 35, 41, 53, and 60 months in the remaining five patients. CONCLUSION: For detection of tumor recurrence/persistence after total thyroidectomy in patients with PTC, one or two sessions of follow-up US during the first 2 years, depending on T and N stages and one session of follow-up US in every second year during the following 8 years may be appropriate.

Korean Thyroid Imaging Reporting and Data System features of follicular thyroid adenoma and carcinoma: a single-center study.

PURPOSE: This study aimed to assess the diagnostic efficacy of Korean Thyroid Imaging Reporting and Data System (K-TIRADS) features for distinguishing follicular thyroid adenoma (FTA) from follicular thyroid carcinoma (FTC). METHODS: From January 2013 to July 2016, 46 follicular neoplasms in 45 patients who underwent preoperative thyroid ultrasonography (US) and thyroid surgery were included. The US features of each thyroid nodule were retrospectively evaluated by a single radiologist using a picture archiving and communication system. The diagnostic indices of K-TIRADS for follicular neoplasms were calculated according to whether K-TIRADS category 4 lesions were excluded or classified as benign or malignant. RESULTS: Of the 46 follicular neoplasms (mean size, 3.1±1.6 cm), 37 were FTAs (mean size, 3.1±1.7 cm) and nine were FTCs (mean size, 3.0±1.5 cm). A statistically significant difference was found between FTAs and FTCs regarding the margin (P=0.035), while no significant differences were observed in the composition, echogenicity, shape, orientation, calcification, or vascularity of the lesions (P<0.05). The FTAs belonged to K-TIRADS categories 3 (n=22) and 4 (n=15), while the FTCs belonged to K-TIRADS categories 3 (n=4), 4 (n=4), and 5 (n=1). However, there was no statistically significant difference in the distribution of K-TIRADS categories between FTAs and FTCs (P=0.184). CONCLUSION: K-TIRADS features were not helpful for distinguishing FTA from FTC, although follicular neoplasms showed a high prevalence of K-TIRADS categories 3 and 4.

Computed Tomography Features of Benign and Malignant Calcified Thyroid Nodules: A Single-Center Study.

OBJECTIVE: No previous studies have investigated thyroid calcification on computed tomography (CT) quantitatively by using Hounsfield unit (HU) values. This study aimed to analyze quantitative HU values of thyroid calcification on preoperative neck CT and to assess the characteristics of benign and malignant calcified thyroid nodules (CTNs). MATERIALS AND METHODS: Two hundred twenty patients who underwent neck CT before thyroid surgery from January 2015 to June 2016 were included. On soft-tissue window CT images, CTNs with calcified components of 3 mm or larger in minimum diameter were included in this study. The HU values and types of CTNs were determined and analyzed. RESULTS: Of 61 CTNs in 49 patients, there were 42 malignant nodules and 19 benign nodules. The mean largest diameter of the calcified component was 5.3 (2.5) mm (range, 3.1-17.1 mm). A statistically significant difference was observed in the HU values of calcified portions between benign and malignant CTNs, whereas there was no significant difference in patient age or sex or in the size, location, or type of each CTN. Of the 8 CTNs with pure calcification, 3 exhibited a honeycomb pattern on bone window CT images, and these 3 CTNs were all diagnosed as papillary thyroid carcinoma on histopathological examination. CONCLUSIONS: Hounsfield unit values of CTNs may be helpful for differentiating malignancy from benignity.

Comparison of computed tomography features between follicular neoplasm and nodular hyperplasia.

BACKGROUND: To date, appropriate management for Bethesda IV thyroid nodules is controversial, and no specific features of follicular neoplasm and nodular hyperplasia on ultrasonography, computed tomography (CT), or other imaging modalities have been reported. This study aimed to compare CT features of follicular neoplasm and nodular hyperplasia and to determine the specific CT features that could be used to distinguish follicular neoplasm from nodular hyperplasia. METHODS: In 122 patients who underwent preoperative CT of the neck and thyroid surgery, 59 follicular neoplasms and 65 nodular hyperplasias were included. In each case, non-enhanced and contrast-enhanced CT images were obtained, and a single radiologist retrospectively analyzed CT images, including degree and pattern of attenuation, nodular configuration, margin, shape, pattern of calcification, degree and pattern of nodular enhancement, and CT halo sign. A univariate and multivariate logistic regression analyses were used to evaluate the predictive power of each variable and CT features with a high predictive power, respectively. RESULTS: According to the univariate analysis, iso-attenuation, intraglandular configuration, smooth margin, ovoid shape, decreased enhancement, and absence of CT halo sign were more frequently observed in nodular hyperplasia (p < 0.05), whereas low attenuation, expansile configuration, lobulated margin, taller-than-wide shape, increased enhancement, and presence of computed tomography halo sign were more frequently observed in follicular neoplasm (p < 0.05). Multivariate analysis revealed significant differences in configuration (OR: 2.73, 1.13-6.57), degree of enhancement (OR: 2.14, 1.21-3.78), and presence of CT halo sign (OR: 7.97, 2.74-23.37) between follicular neoplasm and nodular hyperplasia (p < 0.05). CONCLUSIONS: Neck CT may be helpful for distinguishing follicular neoplasm from nodular hyperplasia. TRIAL REGISTRATION: Rretrospectively registered.