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Hiroyasu Sasajima

Publications and source records attributed to Hiroyasu Sasajima.

7 recordsLinked to original sources
PubMed2006

Surgical decision for adult optic glioma based on [18F]fluorodeoxyglucose positron emission tomography study.

A 51-year-old male presented with a 5-year history of progressive right exophthalmos and visual loss. Magnetic resonance imaging showed a right intraorbital lesion. [(18)F]fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET) revealed high uptake in the tumor. No FDG was accumulated in the remaining optic tract. He underwent removal of the tumor. The histological diagnosis was optic glioma. Six months after the operation, the tumor recurred, and a second operation was performed to spare the visual acuity of the other eye, which remained stable for 1.5 years after the first operation. However, the patient died 2 years after the first operation of liver dysfunction. Adult optic glioma tends to rapidly extend into the surrounding tissue and to affect the contralateral visual pathway. Early diagnosis and surgical intervention are imperative. In the present case, [(18)F]FDG-PET was valuable for evaluating malignancy to determine whether radical surgery was indicated to preserve the remaining visual acuity.

Fluorodeoxyglucose F18↗
PubMed2006

[Orbital schwannoma developing from the superior branch of the oculomotor nerve--case report].

Orbital schwannoma accounts for 1-6% of all orbital tumors and it is not easy to identify the origin of the tumor because of the anatomy of the orbit. A case of orbital schwannoma developing from the superior branch of the oculomotor nerve is reported. A 74-year-old female was admitted to our hospital with the chief complaint of left exophthalmus. MR imaging revealed a space-occupying lesion in the left orbit. Operation was performed through the transcranial approach. It was noticed that the tumor was developing from the nerve that runs into the superior rectus muscle or the levator palpebrae superioris muscle, and it was diagnosed as a schwannoma on frozen section histology during surgery. The tumor was successfully removed and, postoperatively, no additional defects occurred. Careful consideration of microsurgical anatomy is essential for surgery of orbital schwannoma especially when it's necessary to cut the nerves.

Aged↗
PubMed2005

Tractography for arteriovenous malformations near the sensorimotor cortices.

We sought to use diffusion-tensor imaging-based tractography to assess the relationship between the arteriovenous malformations (AVM) and the sensorimotor cortices/tracts. Three patients who had an AVM closely situated to the sensorimotor tracts were studied. The relationship between the sensorimotor tracts and the AVM was well demonstrated in all patients. Tractography was also helpful in identifying the location of the motor cortex in some of the cases.

Adult↗
PubMed2005

Positron emission tomography elucidates transport system and tumor proliferation in meningiomas.

To test the in vivo transport system and tumor proliferation of meningiomas, in comparison with gliomas, 25 patients with meningiomas and 8 gliomas underwent quantitative kinetic analysis of ([18F])fluoro-2-deoxy-D-glucose (FDG) - positron emission tomography (PET) imaging and immunohistochemical study. Kinetic analysis was obtained by calculation of the rate constants: K1 (ml/g/min), which represents the transport of FDG from plasma to tissue; k2 (min(-1)), which demonstrates the transport back from tissue to plasma; and k3 (min(-1)), an indicator of glucose metabolism, using Gjedde's plot methods in a three-compartment model. Surgical specimens were evaluated by means of three different methods: i) immunoreactivity to vascular endothelial growth factor (VEGF) and glucose transporter-1 (Glut-1), representing the permeability of tumor vessels; ii) immunostaining for von Willebrand Factor (vWF), reflecting vascular surface areas of arterioles; and iii) the MIB-1 labeling index (MIB-1 LI), representing the proliferative potential. K1 was higher in meningiomas than in gliomas and was higher in atypical than in benign meningiomas. k3 was correlated with MIB-1 LI in meningiomas, but not in gliomas. Immunohistochemically, meningiomas were less reactive to VEGF or Glut-1 than gliomas but atypical meningiomas stained more intensely than benign meningiomas. The vascular surface area was significantly larger in meningiomas than in gliomas and atypical meningiomas had high values for both permeability and surface area than benign meningiomas. High values for K1 and k3 indicate the aggressive proliferation of meningiomas and, in atypical meningiomas, the synergistic interaction of the high permeability and the large surface area yielded conditions conducive to glucose metabolism and tumor proliferation. Evaluation of K1 and k3 facilitates to predict the tumor aggressiveness and to optimize the surgical management.

Adult↗
PubMed2003

Brain fiber tracking with clinically feasible diffusion-tensor MR imaging: initial experience.

Two technical challenges must be overcome before brain fiber tracking with diffusion-tensor magnetic resonance (MR) imaging can be applied to clinical practice: Imaging time must be shortened, and image distortion must be minimized. Single-shot echo-planar MR imaging with parallel imaging technique enabled both objectives to be accomplished. Twenty-three consecutive patients with brain tumors underwent MR imaging with a 1.5-T whole-body MR system. Fiber tracts on the lesion side in the brain had varying degrees of displacement or disruption as a result of the tumor. Tract disruption resulted from direct tumor involvement, compression on the tract, and vasogenic edema surrounding the tumor. This diffusion-tensor MR imaging method with the parallel imaging technique allows clinically feasible brain fiber tracking.

Adolescent↗
PubMed2003

Spinal intramedullary tuberculoma requiring surgical treatment--case report.

A 71-year-old male presented with multiple central nervous system tuberculomas including spinal intramedullary tuberculoma manifesting as occipitalgia and left hemiparesis. He had received medical treatment for lung and testis tuberculosis. Magnetic resonance imaging revealed an intramedullary lesion at the C-2 level as well as multiple small extramedullary and intracranial lesions. His neurological symptoms gradually worsened despite intensive antituberculous therapy. The C-2 intramedullary lesion responsible for left hemiparesis was surgically extirpated. Postoperatively, his neurological symptoms improved gradually, and no recurrence was evident at the resected site. Surgical intervention is mandatory in patients with intramedullary tuberculoma if neurological symptoms deteriorate or lesions enlarge despite continuous antituberculous therapy.

Aged↗