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Takashi Mimura

Publications and source records attributed to Takashi Mimura.

6 recordsLinked to original sources

Clinical evaluation of color Doppler imaging for the differential diagnosis of thyroid follicular lesions.

Ultrasonography (US) of the thyroid gland has recently proved to be a useful clinical diagnostic method, and the newly developed high-resolution US with a color Doppler flow mapping function can reveal fine details of the thyroid gland and the hemodynamic features of a thyroid neoplasm. US can yield a diagnostic accuracy of more than 90% for thyroid carcinoma, especially papillary carcinoma. However, neither conventional B-mode US imaging nor aspiration biopsy cytology has delivered satisfactory results for follicular carcinoma. The aim of this study was to evaluate the clinical usefulness of color Doppler imaging for the differential diagnosis of thyroid follicular lesions. A color Doppler scan was performed in 310 patients with a solitary cold nodule, and a combination of B-mode US and color Doppler findings, including tumor vascularity and results of a fast Fourier transform (FFT) analysis were used to create the following diagnostic grading system for differential diagnosis of follicular lesions: grade 1, benign follicular lesion [no color flow mapping (CFM) inside the nodule]; grade 2, benign peripheral type [CFM only in peripheral area, pulsatility index (PI) < 1.0]; grade 3, suspected follicular carcinoma (penetrating CFM, vascularity moderate); grade 4, follicular carcinoma (high-velocity penetrating CFM, PI = 1.0). All patients were subjected to surgical resection, and histologic examination was used to confirm the diagnosis. The grades of the 177 adenomatous nodules were as follows: grade 1, 46.9%; grade 2, 48.0%; grade 3, 5.1%; grade 4, 0%. The corresponding percentages for the 89 follicular adenomas were 16.9%, 49.4%, 30.3%, and 3.4%; and for the 44 follicular carcinomas they were 0%, 13.6%, 45.5%, and 40.9%. On the assumption that grade 1 and 2 lesions are benign and grade 3 and 4 lesions are malignant, 38 of the 44 follicular carcinomas and 227 of the 266 benign tumors had been accurately diagnosed, yielding a sensitivity of 88.9%, a specificity of 74.2%, and an accuracy of 81.0% for the grading system. Color Doppler imaging of 310 follicular tumors has revealed that high-velocity pulsatile blood flow penetrating the tumor is a characteristic finding of follicular carcinoma and is a new diagnostic criterion for performing color Doppler imaging. The differential diagnostic grading scores for color Doppler examinations and the results of FFT analysis demonstrate that US with the color Doppler function can play an important role in the differential diagnosis of thyroid tumors.

Adenoma↗

Surgical treatment of Graves' disease in children.

Thyroidectomy may be indicated in children with Graves' disease who have adverse reactions to antithyroid drugs or who relapse after antithyroid drug therapy. We investigated the characteristics of childhood Graves' disease from the standpoint of surgical outcome. Between 1989 and 1998, 1897 patients with Graves' disease underwent thyroidectomy and their thyroid function could be evaluated 2 to 3 years after thyroidectomy. The patients were divided into three groups according to age at thyroidectomy: 74 patients were 15 years old or less (children), 345 patients 16 to 20 years of age (adolescents), and 1478 patients 21 years of age or more (adults). The children included higher proportions of patients who had a large goiter (> 100 g), high thyrotropin-binding inhibitory immunoglobulin (TBII) level (> 50%), and small remnant thyroid (< 4 g). At 2 to 3 years after thyroidectomy, the overt recurrence rate of the children, adolescents, and adults was 9.5%, 4.9%, and 5%, respectively. The cumulative recurrence-free rate of the children, adolescents, and adults at 5 years after thyroidectomy was 82%, 90%, and 92%, respectively. Surgical complications were more frequently observed in children. Considering the aggressiveness of childhood Graves' disease, subtotal thyroidectomy with thyroid remnant less than 3 g is the procedure of choice for preventing recurrent hyperthyroidism.

Adolescent↗

Lymph node metastasis from 259 papillary thyroid microcarcinomas: frequency, pattern of occurrence and recurrence, and optimal strategy for neck dissection.

OBJECTIVE: To determine the frequency and pattern of lymph node metastasis (LNM) from papillary thyroid microcarcinoma (PTMC) and the results of node dissection, and to establish the optimal strategy for neck dissection in these patients. SUMMARY BACKGROUND DATA: Most PTMCs carry a favorable prognosis, but a few present with palpable lymphadenopathy. Patients with LNM are at risk for nodal recurrence, although they do not have higher mortality. The frequency and pattern of LNM from PTMC and the results of node dissection are not well established. METHODS: The frequency and pattern of LNM from 259 PTMCs were analyzed according to the size and location of the primary tumor. Of the 259, 24 with palpable nodes underwent therapeutic node dissection and the other 235 patients without palpable nodes underwent prophylactic node dissection. The authors compared the results of node dissection between the therapeutic group and the prophylactic group, and between PTMCs 5 mm or smaller and PTMCs larger than 5 mm. The authors also compared nodal recurrence between the prophylactic group and a no-lymph-node-dissection group (155 PTMCs). RESULTS: Overall, 64.1% (166/259) and 44.5% (93/209) had node involvement of the central and ipsilateral lateral compartment, respectively. Pretracheal (43.2%), ipsilateral central (36.3%), and ipsilateral mid-lower (37.8%) jugular were more commonly involved. LNM was more frequent in the therapeutic group than in the prophylactic group (95.8% vs. 60.9% for central compartment, 83.3% vs. 39.5% for ipsilateral lateral compartment). Nodal recurrence was more common in the therapeutic group than in the prophylactic group (16.7% vs. 0.43%), but did not differ between the prophylactic group and the no-dissection group (0.43% vs. 0.65%). The tumor size did not influence nodal recurrence. Nodal recurrence preferentially occurred in ipsilateral mid-lower jugular nodes. CONCLUSIONS: Patients who have PTMC presenting with palpable lymphadenopathy should have therapeutic node dissection. Prophylactic node dissection is not beneficial in those without palpable lymphadenopathy.

Adolescent↗

[Sjören's syndrome with infiltrative lung disease showing upper lung field predominance].

We report two cases of Sjören's syndrome (SjS) with infiltrative lung disease showing upper lung field predominance. Case 1 was seen in a 68-year-old woman, who was admitted with dyspnea on exercise. Chest CT scanning demonstrated a central predominance of irregularly shaped consolidation with tractionectasis, distributed along the broncho-vascular bundles in both upper lobes. Case 2 occurred in a 70-year-old woman, who was admitted with cough. Chest CT scan showed a central predominance of irregularly shaped opacities with multiple small cystic structures in both upper lobes. Both cases were shown to be nonspecific interstitial pneumonia (NSIP) by video-assisted thoracoscopic lung biopsy, in which lung involvements were distributed around the bronchovascular sheath with relative sparing of the subpleural region. Although neither case complained of sicca symptoms, decreased saliva production was detected using the Saxon test, and further examinations revealed the presence of primary SjS. Pulmonary involvement in SjS is variable, and distribution along the broncho-bronchioles in the majority of the upper central lung field is a characteristic appearance of SjS lung disease. In patients with such patterns in chest radiography, further diagnostic differentiation should be conducted to confirm or rule out SjS.

Aged↗

The important role of operations in the management of anaplastic thyroid carcinoma.

BACKGROUND: Anaplastic thyroid carcinoma is a rare and highly lethal neoplasm. We investigated whether operations have an impact on the survival of patients who have anaplastic carcinoma without distant metastasis. METHODS: Between 1989 and 1999, 40 consecutive patients with anaplastic carcinoma, without distant metastasis at the time of presentation or during local treatment, were reviewed. The cumulative survival rates and 1-year survival rates were compared. RESULTS: Eleven patients had a small focus of anaplastic carcinoma in a differentiated carcinoma, and 29 patients had ordinary anaplastic thyroid carcinoma. Surgical debulking was performed in 26 patients. Radiotherapy was used for 31 patients and chemotherapy for 19 patients. The 1-year survival rates of the patients with incidental anaplastic carcinoma, ordinary anaplastic carcinoma who underwent operations, and ordinary anaplastic carcinoma who did not undergo operations were 73%, 60%, and 21%, respectively. A significantly higher cumulative survival rate was observed in patients with incidental anaplastic carcinoma than in those with ordinary anaplastic carcinoma. A significantly better outcome was obtained by surgical debulking of ordinary anaplastic carcinoma. CONCLUSIONS: Patients with incidental anaplastic carcinoma tended to have a good outcome, but some had a poor prognosis. Surgical debulking improved the outcome of patients with ordinary anaplastic carcinoma.

Carcinoma↗