Biomedical subjects

Yasuji Oshiro

Publications and source records attributed to Yasuji Oshiro.

4 recordsLinked to original sources

PubMed2004

CT findings of surgically resected large cell neuroendocrine carcinoma of the lung in 38 patients.

OBJECTIVE: We sought to assess the CT features of surgically resected large cell neuroendocrine carcinoma of the lung. MATERIALS AND METHODS: The cases of all patients who underwent surgical resection for primary lung cancer in a single institution from 1993 to 2000 and who received an initial diagnosis of poorly differentiated non-small cell lung carcinoma, small cell carcinoma, carcinoid tumor, and large cell neuroendocrine carcinoma were histologically reviewed. The findings for 43 patients were histologically reclassified and confirmed as large cell neuroendocrine carcinoma. The CT scans available for 38 patients were evaluated by two observers. RESULTS: In the 38 patients, six central tumors and 32 peripheral tumors, with diameters ranging from 12 to 92 mm (mean +/- SD, 32 +/- 19 mm), were identified. None of the tumors had air bronchograms or calcification in the mass or nodule. Of the 19 patients with thin-section CT scans, 14 (74%) showed the tumor-lung interface as well defined and five (26%) showed the interface to be ill defined. Lobulation was identified on 15 scans (79%) and spiculation was evident on six scans (32%). On contrast-enhanced CT scans, inhomogeneously enhanced tumors appeared to be larger (51 +/- 18 mm) than homogeneously enhanced tumors (25 +/- 10 mm; p < 0.001). At histopathologic examination, gross necrosis was noted in 20 of 28 patients who had undergone contrast-enhanced CT, and the cause of inhomogeneous enhancement on CT scans was determined to be intratumoral necrosis. Multiple microscopic necroses were present in all 28 patients. CONCLUSION: Large cell neuroendocrine carcinoma usually appears as a well-defined and lobulated tumor with no air bronchograms or calcification. The inhomogeneous enhancement (caused by necrosis) seen in large cell neuroendocrine carcinomas with large diameters is not necessarily apparent in small-diameter (< 33 mm) large cell neuroendocrine carcinomas, even if the tumor contains necrosis.

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PubMedDate not supplied

Intrapulmonary lymph nodes: thin-section CT features of 19 nodules.

PURPOSE: The purpose of this study was to describe the thin-section CT features of intrapulmonary lymph nodes that accompanied primary or metastatic lung tumors. METHOD: A retrospective analysis of thin-section CT features was performed on 19 nodules in 16 patients with pathologically confirmed intrapulmonary lymph nodes that accompanied primary or metastatic lung tumors. RESULTS: Of the 16 patients, 13 had a solitary nodule and 3 had two nodules. All nodules were distributed in the middle lobe, lingula, or lower lobe. On thin-section CT images, the nodule was located abutting the visceral pleura (n = 10) or within 8 mm of the visceral pleura (n = 9). The thin-section CT findings showed that most of the nodules were well circumscribed (n = 18), homogeneous (n = 19), ovoid (n = 10), or round (n = 9) and smaller than 12 mm in maximal diameter. The surrounding lung field was normal (n = 16). CONCLUSION: Intrapulmonary lymph nodes are subpleural in the lower lung field. On thin-section CT, they are well circumscribed, homogeneous, round or ovoid, and smaller than 12 mm in maximal diameter. In the differential diagnosis of subpleural nodules located in the lower lung field, it should be kept in mind that they may be intrapulmonary lymph nodes even though the patient has malignancy.

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PubMedDate not supplied

Risk factor of radiation pneumonitis: assessment with velocity-encoded cine magnetic resonance imaging of pulmonary artery.

OBJECTIVE: The aim of this study was to investigate whether the pulmonary arterial flow obtained as a function of time from velocity-encoded cine (VEC) magnetic resonance (MR) imaging can be used to predict radiation pneumonitis. METHODS: Before receiving radical radiotherapy, 19 patients with primary lung cancer and 21 with primary esophageal cancer underwent VEC MR imaging to determine their pulmonary arterial flow. The right and left pulmonary arterial flow profiles were digitized, and from these data, acceleration time, maximal change in flow rate during ejection, acceleration volume, and the ratio of maximal change in flow rate during ejection to acceleration volume were measured. The statistical significance of differences in pulmonary arterial flows before irradiation between patients who developed and did not develop RP greater than grade 1 was determined. RESULTS: Radiation pneumonitis occurred in 5 patients with lung cancer and in 4 with esophageal cancer. The acceleration time (P < 0.001), acceleration volume (P < 0.02), and ratio of the maximal change in flow rate during ejection to acceleration volume (P < 0.002) in patients with and without RP were significantly different. The sensitivity, specificity, and accuracy of using 111 milliseconds as the cutoff value (which was the mean acceleration time in the RP group) to predict RP were 58%, 88%, and 83%, respectively. CONCLUSIONS: Pulmonary hypertension detected by VEC MR imaging can be a risk factor for development of RP in candidates for pulmonary irradiation.

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PubMedDate not supplied

Pulmonary dirofilariasis: computed tomography findings and correlation with pathologic features.

OBJECTIVE: The purpose of this study was to describe the computed tomography (CT) and pathologic features of 5 nodules of pulmonary dirofilariasis in 4 patients. METHODS: Four patients with 5 nodules of pathologically confirmed pulmonary dirofilariasis who under went CT were enrolled, and the imaging interpretations were retrospectively compared with the histopathologic characteristics. RESULTS: Three of the 4 patients had a solitary nodule, and the remaining patient had 2 nodules. All the nodules were distributed in the right lower lobe and were attached to the pleura. They were all round or oval in shape and ranged in size from 11 to 22 mm in largest diameter (mean=17 mm). On thinner section CT, the nodules had a well-defined smooth margin with or without a shallow notch; they were connected to the arterial branch and, occasionally, to the venous branch. On contrast-enhanced CT, all the nodules contained a homogeneous low-attenuation area, which corresponded to areas of coagulative necrosis on histopathologic examination. CONCLUSION: Although the CT findings of a pulmonary dirofilariasis nodule are nonspecific, awareness of the findings on contrast-enhanced CT and the pathologic appearance of this rare benign condition may facilitate its differentiation from a malignant nodule.

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