• Korean Journal of Radiology
• /
• v.23 no.10
• /
• pp.1019-1027
• /
• 2022

Objective: Thyroidectomy bed lesions frequently show suspicious ultrasound (US) features after thyroid surgery. Fine-needle aspiration (FNA) may not provide definitive pathological information about the lesions. Although core-needle biopsy (CNB) has excellent diagnostic performance in characterizing suspicious thyroid nodules, no published studies have evaluated the performance of CNB specifically for thyroidectomy bed lesions. Therefore, we aimed to evaluate the diagnostic performance and safety of CNB for characterizing thyroidectomy bed lesions. Materials and Methods: A total of 124 thyroidectomy bed lesions in 113 patients (79 female and 34 male; age, 23-85 years) who underwent US-guided CNB between December 2008 and December 2020 were included. We reviewed the US imaging features of the target lesions and the histories of previous biopsies. The pathologic results, diagnostic performance for malignancy, and complications of CNB were analyzed. Results: All samples (100%) obtained by CNB were adequate for pathological analysis. Pathological analysis revealed inconclusive results in two lesions (1.6%). According to the reference standard, 50 lesions were ultimately malignant (40.3%), and 72 were benign (58.1%), excluding the two inconclusive lesions. The performance of CNB for diagnosing malignant thyroidectomy bed lesions in the 122 lesions had a sensitivity of 98.0% (49/50), a specificity of 100% (72/72), positive predictive value of 100% (49/49), and negative predictive value of 98.6% (72/73). Eleven lesions were referred for CNB after prior inconclusive FNA results in thyroidectomy bed lesions, for all of which CNB yielded correct conclusive pathologic diagnoses. According to the pathological analysis of CNB, there were various benign lesions (58.9%, 73/124) besides recurrence, including benign postoperative lesions other than suture granuloma (32.3%, 40/124), suture granuloma (15.3%, 19/124), remnant thyroid tissue (5.6%, 7/124), parathyroid lesions (4%, 5/124), and abscesses (1.6%, 2/124). No major or minor complications were associated with the CNB procedure. Conclusion: US-guided CNB is accurate and safe for characterizing thyroidectomy bed lesions.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.37 no.2
• /
• pp.224-234
• /
• 2013

This study investigates the fabrication of core-sheath nanocomposite fibers by locating germanium (Ge) and silicon dioxide ($SiO_2$) nanoparticles selectively in the sheath layer by co-axial electrospinning. Co-axially spun fibers were prepared by electrospinning a pure PVA solution and Ge/$SiO_2$/PVA solution as the core and sheath layer, respectively. Core-sheath nanocomposite fibers were electrospun under a variety of conditions that include various feed rates for the core and sheath solutions, voltages, and concentric needle diameters, in order to find an optimum spinning condition. Ge/$SiO_2$ nanocomposite fibers were also prepared by uniaxial electrospinning to compare fiber morphology and nanoparticle distribution with core-sheath nanofibers. Using scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis, it was demonstrated that the co-axial approach resulted in the presence of nanoparticles near the surface region of the fibers compared to the overall distribution obtained for uni-axial fibers. The co-axially electrospun Ge/$SiO_2$/PVA nanofiber webs have possible uses in high efficiency functional textiles in which the nanoparticles located in the sheath region provide enhanced functionality.

• Journal of Power System Engineering
• /
• v.3 no.3
• /
• pp.22-28
• /
• 1999

The injected liquid does not break-up instantly after injection for diesel engine. There is some unbroken portion, which is the liquid core(The length of liquid core is called the break-up length) in the spray. If the liquid core is longer than the depth of the bowl in the small DI diesel engine, the liquid core impinges on the surface of the piston. Once the liquid core impinges on the surface, it cannot ignite or burn rapidly and thus prolongs burning time with a degradation in thermal efficiency. The break-up length of a diesel spray in a compressure vessel was measured by an electric resistance method, A voltage was applied between the nozzle and screen, bar, needle electrode inserted at various axial and radial positions into atomizing sprays. As a result, a current flows not only in the region of liquid core but also through the droplets of the spray. It is found that the break-up length measured with screen electrode is overestimated. The break-up length of the spray is found to be proportional to the square root of the density ratio of fuel and surrounding gas. The break-up length of the spray decreases as the injection pressure and the back pressure increase.

• The Korean Journal of Cytopathology
• /
• v.9 no.1
• /
• pp.55-61
• /
• 1998

To compare the diagnostic yields and complication rates of transthoracic fine needle aspiration cytology(FNAC) and gun biopsy in the diagnosis of pulmonary mass, a retrospective review was performed in 125 cases. Under the fluoroscopic guide, FNAC was performed by 20G Chiba needle in 91 cases, core biopsy was done by 18.5 G vaccum needle attached with automated biopsy gun in 74 cases and both procedures were done together in 37 cases. Overall sensitivity was 88.4% in FNAC and 87.5% in gun biopsy. For malignant pulmonary tumors, correct type correlation with final diagnosis was obtained in 33(76.7%) out of 43 cases by FNAC and 30(75.0%) out of 40 cases by gun biopsy. For benign pulmonary lesions, there were correct type correlation in 14(35.0%) out of 40 cases by FNAC and 14(53.8%) out of 26 cases by gun biopsy. The complication was pneumothorax and hemoptysis. Pneumothorax occured in 11.1% of FNAC, 10.9% of gun biopsy and 10.9% of both technique, among which chest tube drainages were necessary in one patient by gun biopsy and in three patients by both technique. Although no significant difference of diagnositc accuracy and complication rate was found between FNAC and gun biopsy, gun biopsy was more helpful in the diagnosis of pulmonary benign lesions than FNAC.

• Korean Journal of Radiology
• /
• v.20 no.6
• /
• pp.947-955
• /
• 2019

Degenerating nodules (DNs), which primarily manifest as benign thyroid nodules, are one of the main causes of discordance in ultrasonography (US) and cytological assessments. Intranodular hemorrhage is one of the mechanisms contributing to discordant nodules, and an impaired blood supply may explain further DN shrinkage and infarction. The surgical specimens can be divided into acute and chronic stages based on the histological changes, which usually mimic the US features of malignant tumors. Serial US follow-up should be recommended instead of other unnecessary procedures. However, repeated fine-needle aspiration, diagnostic surgery, or core-needle biopsy may still be necessary for indeterminable or highly suspicious DNs.

• The Korean Journal of Cytopathology
• /
• v.2 no.1
• /
• pp.43-50
• /
• 1991

A case of malignant epithelial mesothelioma of the peritoneum diagnosed by fine needle aspiration cytology is described. The smear showed many Individually scattered or clustered large round malignant epithelial cells intermingled with relatively small nonneoplastic mesothelial and mesenchymal cells. Papillary configurations with thick fibrous core were also seen. The malignant cells were virtually reminiscent of reactive mesothelial cells but they were larger in size and had more prominent nucleoli and more frequent binucleated or multinucleated cell formations than reactive mesothelial cells. The characteristic features of malignant cell of mesothelioma compared with the metastatic adenocarcinoma were relatively uniform cellular size, prominent round nucleoli, large round vesicular nuclei with finely granular chromatin pattern, smooth nuclear membrane, abundant glassy cytoplasm rather than bubbly mucin-containing cytoplasm and fuzzy cell border.

• Tuberculosis and Respiratory Diseases
• /
• v.71 no.6
• /
• pp.408-416
• /
• 2011

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a technique developed to allow mediastinal staging of lung cancer and also to evaluate intrathoracic lymphadenopathy. In a tuberculosis-endemic area, tuberculosis should be considered as an etiology of mediastinal lymphadenopathy. The aim of this study was to investigate the utility of the routine culture for tuberculosis from specimens of EBUS-TBNA. Methods: We prospectively performed routine culture for tuberculosis from aspiration or core biopsy specimens got from 86 patients who had undergone EBUS-TBNA due to mediastinal lymphadenopathy between March 2010 and March 2011. Results: A total of 135 lymph node aspiration and 118 core biopsy specimens were included in this analysis. We confirmed the malignancy in 62 (72.9%), tuberculosis in 7 (8.1%), sarcoidosis in 7 (8.1%), asperogillosis in 2 (2.3%) and pneumoconiosis in 2 (2.3%) patients. One lung cancer patient had pulmonary tuberculosis coincidentally and 5 patients had unknown lymphadenopathy. The number of positive culture for Mycobacterium tuberculsosis by EBUS-TBNA is 2 (1.5%) from 135 lymph node aspiration specimens and 2 (1.7%) from 118 core biopsy specimens. Out of eight patients confirmed with tuberculosis, only one patient had positive mycobacterial culture of aspiration specimen from EBUS-TBNA without histopathologic diagnosis. Conclusion: These results propose that routine culture for tuberculosis from EBUS-TBNA may not provide additional information for the diagnosis of coincident tuberculous lymphadenitis. However, if there is any possibility of tuberculous lymphadenopathy or pulmonary tuberculosis, it should be considered to perform EBUS-TBNA in patients who have negative sputum AFB smears or no sputum production.

• Korean Journal of Radiology
• /
• v.21 no.4
• /
• pp.422-430
• /
• 2020

The Korean Society of Urogenital Radiology (KSUR) aimed to present a consensus statement for patient preparation, standard technique, and pain management in relation to transrectal ultrasound-guided prostate biopsy (TRUS-Bx) to reduce the variability in TRUS-Bx methodologies and suggest a nationwide guideline. The KSUR guideline development subcommittee constructed questionnaires assessing prebiopsy anticoagulation, the cleansing enema, antimicrobial prophylaxis, local anesthesia methods such as periprostatic neurovascular bundle block (PNB) or intrarectal lidocaine gel application (IRLA), opioid usage, and the number of biopsy cores and length and diameter of the biopsy needle. The survey was conducted using an Internet-based platform, and responses were solicited from the 90 members registered on the KSUR mailing list as of 2018. A comprehensive search of relevant literature from Medline database was conducted. The strength of each recommendation was graded on the basis of the level of evidence. Among the 90 registered members, 29 doctors (32.2%) responded to this online survey. Most KSUR members stopped anticoagulants (100%) and antiplatelets (76%) one week before the procedure. All respondents performed a cleansing enema before TRUS-Bx. Approximately 86% of respondents administered prophylactic antibiotics before TRUS-Bx. The most frequently used antibiotics were third-generation cephalosporins. PNB was the most widely used pain control method, followed by a combination of PNB plus IRLA. Opioids were rarely used (6.8%), and they were used only as an adjunctive pain management approach during TRUS-Bx. The KSUR members mainly chose the 12-core biopsy method (89.7%) and 18G 16-mm or 22-mm (96.5%) needles. The KSUR recommends the 12-core biopsy scheme with PNB with or without IRLA as the standard protocol for TRUS-Bx. Anticoagulants and antiplatelet agents should be discontinued at least 5 days prior to the procedure, and antibiotic prophylaxis is highly recommended to prevent infectious complications. Glycerin cleansing enemas and administration of opioid analogues before the procedure could be helpful in some situations. The choice of biopsy needle is dependent on the practitioners' situation and preferences.

• Journal of the Korean Society of Radiology
• /
• v.81 no.3
• /
• pp.719-725
• /
• 2020

Metastases to the thyroid gland have rarely been reported in clinical settings, and the thyroid gland is an uncommon site for breast carcinoma metastasis. We report a case of a 64-year-old breast cancer patient diagnosed with metastatic breast carcinoma in the thyroid gland after performing ultrasonography (US)-guided core needle biopsy (CNB) and subsequent total thyroidectomy. On US, the thyroid lesion appeared to be mildly enlarged with multiple internal hypoechoic lines and a few microcalcifications without mass formation. Under US-guidance, CNB was performed by targeting the area with microcalcifications and subsequently diagnosed as metastatic breast carcinoma. Total thyroidectomy revealed that the patient had metastatic invasive ductal carcinoma of the breast with lymphatic spread involving both lobes and the isthmus of the thyroid gland. Although the thyroid gland is an uncommon metastatic site, the unusual features of thyroid metastasis can be observed on US; thus, US-guided CNB effectively aids the diagnosis of thyroid metastasis.

• Tuberculosis and Respiratory Diseases
• /
• v.71 no.5
• /
• pp.355-358
• /
• 2011

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a useful, safe diagnostic modality for evaluating mediastinal and hilar lymphadenopathy. We report a 51-year-old male who presented with a left renal mass and multiple pleural masses without lung parenchymal lesions. The pleural masses were thought to be metastatic tumors or malignant mesothelioma. The patient underwent two percutaneous needle biopsies of the pleural mass, but the specimens were insufficient for a histopathological diagnosis. Because one pleural mass was adjacent to the right main bronchus, we decided to perform EBUS-TBNA for the pleural mass. As a result, sufficient core tissue was obtained with no complications, and the histopathological findings were consistent with metastatic papillary renal cell carcinoma. To our knowledge, this is the first case of using EBUS-TBNA for a pleural mass.