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Biomedical subjects

T Maehara

Publications and source records attributed to T Maehara.

At least 199 records · Page 11Linked to original sources
PubMed1979

Ossification of the posterior longitudianl ligament of the cervical spine: subtotal vertebrectomy as a treatment.

If the ossification is localized in the central part of the intervertebral space, anterior decompression surgery of Cloward may be indicated. However, if most posterior ligamentous ossification covers the posterior surface of the vertebral body and the lateral sides, Cloward's method is not indicated. We have developed a method of anterior decompression and fusion surgery to clear the ossified area, resecting the vertebral body (subtotal vertebrectomy). The results were excellent in 3 of 4 patients with preoperative radiculopathy; there were 2 excellent and 16 good results in 22 patients with myelopathy. Of course laminectomy can produce some good effects, but the anterior obstruction removes through the anterior approach. Anterior decompression may be indicated when ossification is localized below the C3--4 intervertebral space, and when the spinal canal is not narrowed in the upper cervical region, even if ossification extends over the whole cervical spine. Laminectomy is advised when ossification involves all levels of the cervical spine, the upper cervical spine is narrowed or the sagittal dimension of the spinal canal is reduced more than 60%.

Cervical Vertebrae↗
PubMed1978

Cerebral venous angioma: computerized tomography and angiographic diagnosis.

Four cases of cerebral venous angioma were studied by both CT and angiography. All cases showed similar angiographic findings: a normal arterial phase and a local network of small veins that converged centrally into a single large draining vein. However, CT showed nodular areas of high density in three cases, and a curvilinear enhanced lesion representing the draining vein in the other. CT findings are nonspecific but very useful for detecting the lesion and demonstrating the associated hematoma. Angiographic findings are not so obvious as in AVM, but are necessary for the final diagnosis of the venous angioma.

Adult↗
PubMedDate not supplied

Management of branch duct-type intraductal papillary mucinous tumor of the pancreas based on magnetic resonance imaging.

BACKGROUND: We assessed the usefulness of magnetic resonance imaging (MRI) in identifying nonmalignant intraductal papillary mucinous tumors (IPMTs) of the pancreas. METHODS: Thirty-three patients with branch duct-type IPMT diagnosed by endoscopic retrograde cholangiopancreatography were prospectively examined with magnetic resonance cholangiopancreatography followed by dynamic gadolinium-enhanced MRI examinations, and patients with no findings suggestive of malignancy, including a solid mass, mural nodules, a main pancreatic duct wider than 5 mm in diameter, and stenosis of the main pancreatic duct, were prospectively followed up with sequential MRI examinations once or twice a year. RESULTS: Twenty-six (79%) patients showed no findings suggestive of malignancy in the initial MRI examination. The diameter (mean +/- standard error) of the main pancreatic duct was 3.9 +/- 0.7 mm and that of the ectatic branch pancreatic duct was 36.0 +/- 9.1 mm. Twenty-three patients were prospectively followed for more than 36 months and 22 of them showed no findings suggestive of malignancy during follow-up periods ranging from 39 to 77 months (mean = 55 months). CONCLUSION: MRI was useful to identify nonmalignant IPMTs of the branch duct type, and close follow-up observation with serial MRI examinations may be appropriate in the management of such patients.

Adenocarcinoma, Mucinous↗
PubMedDate not supplied

Computed tomography of intracranial chondroma with emphasis on delayed contrast enhancement.

Intracranial chondroma is an unusual cartilaginous tumor originating from the base of the skull. We report on two cases of intracranial chondroma that showed delayed contrast enhancement on CT after high-dose administration of contrast medium. This CT feature may be useful to differentiate chondromas from other tumors of the skull base such as meningiomas and neurinomas.

Adult↗
PubMedDate not supplied

Neurinoma of the oculomotor nerve: CT and MR features.

The authors present a case of neurinoma of the oculomotor nerve without evidence of von Recklinghausen disease. The literature is reviewed and CT and magnetic resonance findings are discussed.

Cranial Nerve Neoplasms↗
PubMedDate not supplied

Combination of surface anatomy MRI and MR venography to demonstrate cerebral cortex and cortical veins on one image.

We assessed in 12 patients the value of MR images in which a surface anatomy scanning (SAS) image and an MR venogram are added. We obtained SAS images using the half-Fourier technique and MR venograms with the 2D phase-contrast technique. The added images provided sufficient information concerning brain surface as well as cortical veins. Their findings correlated with those at surgery in six patients who underwent scalp incision marking. This technique provides valuable anatomical information preoperatively.

Adult↗
PubMedDate not supplied

Rhabdomyosarcoma in a patient with mosaic Klinefelter syndrome and transformation of immature teratoma.

A 27-year-old man was found to have a mediastinal tumour and the histological diagnosis was immature teratoma. Remission was achieved by chemotherapy and total resection. However, he developed anaemia and leukoerythroblastosis after 2 years of remission, and was referred to our hospital. Rhabdomyosarcoma cells were detected in the bone marrow and pleural effusion. Moreover, karyotype analysis of peripheral blood and bone marrow cells revealed mosaic-type Klinefelter syndrome. We diagnosed the case as transformation of teratoma into rhabdomyosarcoma in Klinefelter syndrome. Although intensive chemotherapy was performed, the patient died with meningeal infiltration.

Adult↗
PubMedDate not supplied

Functional magnetic resonance imaging of auditory cortex: with special reference to the side of aural stimulation.

PURPOSE: To determine whether left- or right-side uniaural stimulation produces different fMRI activation patterns. METHODS: Subjects were 12 volunteers (8 right-handed, 4 left-handed) with normal hearing. Functional imaging using FE-type multishot echo planar imaging was obtained in the axial plane during pure-tone and pseudoword tasks. Auditory stimuli were presented to each ear individually. In pure-tone tasks, subjects heard clustered sequences at 2000 Hz. In pseudoword tasks, subjects heard spoken Japanese syllables. The numbers of activated pixels in the auditory cortex were counted and compared for pure-tone and pseudoword tasks, as was activation according to the side of aural stimulation. RESULTS: In right-handed subjects, prominent activation in pure-tone tasks was noted in the dominant hemisphere in 100% of cases and was unrelated to the side of the stimulation. In pseudoword tasks, prominent activation was noted on the side contralateral to the stimulus in 62.5-100% of cases. In left-handed subjects, prominent activation was noted on the side contralateral to the stimulus in both pure-tone and pseudoword tasks. CONCLUSION: Left- and right-side stimulation produced differences in fMRI responses, especially between pure-tone and pseudoword tasks. Moreover, right-handedness and left-handedness affected results. This type of auditory fMRI may be a noninvasive indicator of language lateralization.

Acoustic Stimulation↗
PubMedDate not supplied

Stereotactic radiosurgery for brain metastases using a linac system: evaluation of initial local response by imaging.

PURPOSE: We analyzed the efficacy of initial local response of MBT by imaging obtained within two months after treatment, to determine if there are factors that may be important for the initial local response of the disease. If an earlier local tumor response can be expected from SRS, patients with a poor prognosis should be treated with this modality. METHODS: Thirty-six patients with 59 lesions were treated by linac radiosurgery. The primary tumor, peripheral dose, tumor volume, and CT enhancement pattern of the tumor before treatment (homogeneous or ring-enhancing) were chosen as factors related to local tumor response and were used in the statistical analysis. RESULTS: 1) The initial local response of radiation-resistant tumors to conventional EBRT was worse than that of other tumors. The initial local responses of MBT from breast carcinoma, colon carcinoma, and pulmonary carcinoma were good. 2) Excluding radioresistant tumors, the cases irradiated at 25 Gy or more tended to show good local control. 3) No statistically significant differences were found between local response and factors such as the enhancement pattern and tumor volume in the analysis of MBT.

Brain Neoplasms↗
PubMedDate not supplied

MR images of ovarian carcinosarcoma.

The MR imaging of an ovarian carcinosarcoma is described. The tumor was heterogeneous and showed very high-intensity on T2-weighted images and iso-intensity on T1-weighted images, with visible enhancement. Even though signal intensities were somewhat different from those of ovarian adenocarcinoma, the preoperative diagnosis of ovarian carcinosarcoma is still difficult.

Carcinosarcoma↗