PURPOSE: To realistically map the electric fields of biological tissues using a diffusion tensor magnetic resonance electrical impedance tomography (DT-MREIT) method to estimate tissue response during electrical stimulation. METHODS: Imaging experiments were performed using chunks of bovine muscle. Two silver wire electrodes were positioned inside the muscle tissue for electrical stimulation. Electric pulses were applied with a 100-V amplitude and 100-μs width using a voltage stimulator. During electrical stimulation, we collected DT-MREIT data from a 3T magnetic resonance imaging scanner. We adopted the projected current density method to calculate the electric field. Based on the relation between the water diffusion tensor and the conductivity tensor, we computed the position-dependent scale factor using the measured magnetic flux density data. Then, a final conductivity tensor map was reconstructed using the multiplication of the water diffusion tensor and the scale factor. RESULTS: The current density images from DT-MREIT data represent the internal current flows that exist not only in the electrodes but also in surrounding regions. The reconstructed electric filed map from our anisotropic conductivity tensor with the projected current density shows coverage that is more than 2 times as wide, and higher signals in both the electrodes and surrounding tissues, than the previous isotropic method owing to the consideration of tissue anisotropy. CONCLUSIONS: An electric field map obtained by an anisotropic reconstruction method showed different patterns from the results of the previous isotropic reconstruction method. Since accurate electric field mapping is important to correctly estimate the coverage of the electrical treatment, future studies should include more rigorous validations of the new method through in vivo and in situ experiments.
Anisotropy ; Diffusion Tensor Imaging ; Diffusion* ; Electric Conductivity* ; Electric Impedance ; Electric Stimulation* ; Electrodes ; Magnetic Resonance Imaging ; Methods ; Silver ; Water*

PURPOSE: Adrenal schwannomas are very rare and are usually incidentally found on autopsy and imaging. The aim of this study was to describe our experience of adrenal schwannoma and review the literature regarding this rare tumor. METHODS: To identify patients with adrenal schwannoma, the MEDLINE database was searched via the major electronic database PubMed using the medical subject heading terms “adrenal” and “schwannoma”. Thirty-nine adrenal schwannoma cases, including two from our institution were included. RESULTS: The mean age at diagnosis was 47.95 years (range, 11~89 years). The female:male ratio was 21:17. Sixteen patients had tumors on the right side, 19 on the left, while one patient had bilateral tumors. The mean tumor size was 6.12 cm (range, 0.6~14.5 cm), and the mean tumor weight was 161.3 g (range, 31.5~600.0 g). Sixteen tumors were solid, four cystic, one solid and cystic, and 18 were not described. Histologically, 14 cases were Antoni A, two were Antoni B, and 12 had concomitant Antoni A and B. CONCLUSION: Adrenal schwannoma is usually an incidental finding, and the clinician must have a high index of suspicion to recognize it when imaging reveals suggestive features.
Adrenal Glands ; Autopsy ; Diagnosis ; Humans ; Incidental Findings ; Medical Subject Headings ; Neurilemmoma* ; Tumor Burden

PURPOSE: Although guidelines indicate that routine dissection of the central lymph nodes in patients with thyroid carcinoma should include the right para-oesophageal lymph nodes (RPELNs), located between the right recurrent laryngeal nerve and the cervical oesophagus and posterior to the former, RPELN dissection is often omitted due to high risk of injuries to the recurrent laryngeal nerve and the right inferior parathyroid gland. MATERIALS AND METHODS: We retrospectively identified all patients diagnosed with papillary thyroid carcinoma who underwent total thyroidectomy with central lymph node dissection, including the RPELNs, between January 1, 2009 and December 31, 2013 at the Thyroid Cancer Center of Yonsei University College of Medicine, Seoul, Korea. RESULTS: Of 5556 patients, 148 were positive for RPELN metastasis; of the latter, 91 had primary tumours greater than 1 cm (p<0.001). Extrathyroidal extension by the primary tumour (81.8%; p<0.001), bilaterality, and multifocality were more common in patients with than without RPELN metastasis; however, there were no significant differences in age and sex between groups. A total of 95.9% of patients with RPELN metastasis had central node (except right para-oesophageal lymph node) metastasis, and the incidence of lateral neck node metastasis was significantly higher in patients with than without RPELN metastasis (63.5% vs. 14.3%, p<0.001). Forty-one patients underwent mediastinal dissection, with 11 patients confirmed as having mediastinal lymph node metastasis with RPELN metastasis on pathological examination. CONCLUSION: RPELN metastasis is significantly associated with lateral neck and mediastinal lymph node metastasis.
Adult ; Aged ; Carcinoma/pathology/*surgery ; Carcinoma, Papillary/pathology/*surgery ; Esophageal Neoplasms/*secondary/surgery ; Female ; Humans ; Incidence ; *Lymph Node Excision ; Lymph Nodes/pathology/*surgery ; Lymphatic Metastasis/pathology ; Male ; Middle Aged ; Recurrent Laryngeal Nerve/pathology ; Republic of Korea/epidemiology ; Retrospective Studies ; Thyroid Neoplasms/pathology/*surgery ; *Thyroidectomy ; Treatment Outcome ; Young Adult

PURPOSE: Ultrasound (US) and US-guided fine needle aspiration biopsies (FNAB) are considered the modalities of choice for assessing lymph nodes suspected of containing metastases, but the sensitivity of FNAB varies and is specific to the operator. We analyzed the risk of FNAB providing false negative results of lateral neck node metastasis, and evaluated diagnostic accuracy of FNAB, in patients with papillary thyroid cancer. MATERIALS AND METHODS: FNAB was performed in 242 patients suspected of having lateral neck node metastasis on preoperative imaging. Thyroglobulin in the fine-needle aspirate washout (FNA wash-out Tg) and computed tomography enhancement (Hounsfield units) were measured. Patients with negative results on FNAB were examined by intraoperative frozen section. The false negative and true negative groups were compared. RESULTS: Of the 242 patients, 130 were confirmed as having lateral neck node metastases. In 74 patients, the metastasis was identified by FNAB. False positive results were observed in 2 patients (0.8%) and false negatives in 58 (44.6%). Risk analysis showed that patient age <45 years (p=0.006), tumor size >1 cm (p=0.008) and elevated FNA wash-out Tg (p=0.004) were significantly associated with false negative results on FNAB. The accuracy of FNAB increased significantly when combined with FNA wash-out Tg (p=0.003). CONCLUSION: To reduce the false negative rate of FNAB, patient age (<45 years), tumor size (>1 cm) and FNA wash-out Tg (>34.8 ng/mL) should be considered in preoperative planning. Accuracy may be improved by combining the results of FNAB and FNA wash-out Tg.
Adolescent ; Adult ; Aged ; Biopsy, Fine-Needle ; Carcinoma/*diagnosis/*pathology/radiography/surgery ; False Negative Reactions ; Female ; Humans ; Lymph Nodes/*pathology/radiography ; Lymphatic Metastasis/*pathology/radiography ; Male ; Middle Aged ; Multivariate Analysis ; Preoperative Care ; Risk Factors ; Sensitivity and Specificity ; Thyroglobulin/metabolism ; Thyroid Gland/*pathology ; Thyroid Neoplasms/*diagnosis/*pathology/radiography/surgery ; Tomography, X-Ray Computed ; Young Adult

BACKGROUND AND OBJECTIVES: To prevent getting wrong information and improve high quality of life, it is necessary to provide accurate information and patient education. This study aimed to collect basic data and develop educational program for thyroid cancer patient by understanding their educational needs. MATERIALS AND METHODS: Between April 16 and June 15, 2012, 159 patients who underwent thyroid cancer surgery were enrolled. This survey consisted of 5 areas including management of the symptom and the complication after surgery, postoperative wound and dietary management, treatment plan after discharge, medication management, and daily life. RESULTS: The most common way for the patients to acquire information about the disease was Internet and the patients who used INTERNET as their information source were 54.7%. Doctors (76.1%) and nurses (21.4%) were the preferred educators for the patients, and small group education was the preferred education method. Specifically the need for "management of the symptom and the complication after surgery" was the highest (3.33), followed by "treatment plan after discharge" (3.31), "medication management" (3.19), "postoperative wound and dietary management" (3.17). CONCLUSION: Medical team including doctors and nurses should be the center to activate small group education for patients. Professional and individualized education program should be developed to give the proper education to patients and their family.
Education ; Health Surveys ; Humans ; Internet ; Methods ; Patient Education as Topic ; Quality of Life ; Thyroid Gland* ; Thyroid Neoplasms* ; Wounds and Injuries

PURPOSE: The cervical lymph nodes are the most common sites of locoregional recurrence in patients with papillary thyroid carcinoma (PTC). Accurate tumor localization is important for the successful removal of impalpable recurrences in the cervical lymph nodes. We evaluated the benefits of ultrasound-guided localization (UGL) performed by a single surgeon on site. METHODS: Of 53 PTC patients who underwent reoperation for impalpable nodal recurrences, 32 (group 1) were assessed only using preoperative imaging, while 21 (group 2) were additionally evaluated by on-site UGL performed by the operating surgeon. Postoperative outcomes were compared between the two groups. RESULTS: Operation times were significantly shorter (P < 0.001) and the mean size of the resected lymph nodes were smaller (P = 0.013) for group 2 patients. More lymph nodes were identified and resected in group 1 (3.56 vs. 3.19), but the rate of positive lymph nodes was significantly higher in group 2 (P < 0.001). There were no differences between the two groups in terms of resection success rate, complication rate, and postoperative hospital stay. During a mean follow-up period of 27.6 months, 52 patients (98.1%) showed no evidence of recurrence on routine ultrasound, and serum thyroglobulin concentrations remained < 1 ng/mL in 49 patients (92.5%). CONCLUSION: On-site UGL performed by the operating surgeon is useful for accurate resection of impalpable nodal recurrences in PTC patients.
Carcinoma ; Factor IX ; Follow-Up Studies ; Humans ; Length of Stay ; Lymph Nodes ; Recurrence ; Reoperation ; Thyroglobulin ; Thyroid Gland ; Thyroid Neoplasms

PURPOSE: This study was conducted to investigate whether the use of HA-CMC solution in thyroid surgery influences drainage amount and hospital stay. METHODS: Between November 2012 and December 12, 147 patients with thyroid cancer who underwent total thyroidectomy with central compartment neck dissection were analyzed retrospectively. The patients were divided into four groups; those with or without HA-CMC solution application and high or low output drainage. RESULTS: There were no differences in hospital stay and mean total drainage between the with and without HA-CMC solution application groups (P=0.230, P=0.732). The mean hospital stay was 2.2±0.4 days for the low output of drainage group and 3.1±0.6 days for the high output drainage group (P<0.001). There was no significant difference in the use of HA-CMC solution (41.1% vs. 56.8%, P=0.070). CONCLUSION: The use of HA-CMC solution in thyroid cancer surgery might not increase drainage amount and make hospital stay longer.
Drainage* ; Humans ; Length of Stay ; Neck Dissection ; Retrospective Studies ; Thyroid Gland* ; Thyroid Neoplasms* ; Thyroidectomy

Histologic patterns at tumor margins may be related to prognosis in several malignancies. We investigated tumor aggressiveness with respect to tumor margin histology in patients with papillary thyroid carcinoma (PTC). Five hundred fourteen consecutive patients who underwent surgery for primary PTC between January and July 2009 were assigned to two groups, one with an infiltrative pattern (I-type, n = 347) at tumor margins and one with an expanding pattern (E-type, n = 167). Tumor aggressiveness was assessed by analyzing relationships between these patterns and known prognostic factors. The analysis showed that unfavorable prognostic factors such as tumor multiplicity (P = 0.002), extrathyroidal extension (P < 0.001), lateral neck lymph node metastasis (P < 0.001) and advanced TNM stage (P = 0.001) were significantly more prevalent in patients with I-type PTC than in those with the E-type. Central neck node metastases were more prevalent without statistical significance in the I-type patients (P = 0.376). Tumor margin histology was not related to gender or tumor size. These results suggest that histologic patterns at tumor margins predict aggressiveness in PTC.
Adult ; Cell Proliferation ; Female ; Humans ; Lymphatic Metastasis ; Male ; Middle Aged ; Neoplasm Invasiveness ; Neoplasm Staging ; Prognosis ; Thyroid Neoplasms/epidemiology/*pathology

Paraffinoma is a well known complication of previous paraffin injection into the subcutaneous layer that presents as various conditions including firm mass formation, edema, induration, ulceration, and skin necrosis. Paraffinoma can mimic neoplasm on physical examination and imaging studies and may complicate ultrasonographic diagnoses due to typical posterior shadowing and high echogenicity. When paraffinomas involve around the thyroid gland, the diagnosis of thyroid tumors is very difficult. We present a case of thyroid cancer, the evaluation of which was complicated by the presence of cervical paraffinoma.
Edema ; Hydrazines ; Necrosis ; Paraffin ; Physical Examination ; Shadowing (Histology) ; Skin ; Thyroid Gland ; Thyroid Neoplasms ; Ulcer

Primary neuroendocrine carcinomas are uncommon highly malignant tumors of the genitourinary tract, and they have a poor prognosis. We report here on a case of a primary neuroendocrine carcinoma of the urethra that developed after radical cystectomy and ileal conduit diversion for treating transitional cell carcinoma of the urinary bladder.