Biomedical subjects

Yoshikatsu Seiki

Publications and source records attributed to Yoshikatsu Seiki.

5 recordsLinked to original sources

PubMed2003

[A rare massive parenchymal metastasis in central nervous system from abdominal non-Hodgkin lymphoma: effectiveness of stereotactic radiosurgey: case report].

A 62-year-old female presented with a rare massive parenchymatous metastasis from abdominal malignant lymphoma. Computed tomography and magnetic resonance image revealed a large enhanced mass in the right basal ganglia. 123I-IMP SPECT showed increased uptake on both early and delayed images. A stereotactic biopsy was performed; histological examination revealed a diffuse large B-cell malignant lymphoma. The patient underwent stereotactic radiosurgery (SRS). Short-term cliniconeuroradiological follow-up showed both neurologic improvement and virtually complete disappearance of the tumor. Our findings suggest that 123I-IMP SPECT can help differentiate malignant lymphoma from benign lesions and other malignant brain tumors. In addition, SRS with conventional radiotherapy may be an effective therapeutic strategy to control malignant lymphoma.

Abdominal Neoplasms↗

PubMed2003

[Peritumoral hemorrhage immediately after radiosurgery for metastatic brain tumor].

We report a case of a 44-year-old woman with metastatic brain tumors who suffered peri-tumoral hemorrhage soon after stereotactic radiosurgery (SRS). She had been suffering from breast cancer with multiple systemic metastasis. She started to have headache, nausea, dizziness and speech disturbance 1 month before admission. There was no bleeding tendency in the hematological examination and the patient was normotensive. Neurological examination disclosed headache and slightly aphasia. Magnetic resonance imaging showed a large round mass lesion in the left temporal lobe. It was a well-demarcated, highly enhanced mass, 45 mm in diameter. SRS was performed on four lesions in a single session (Main mass: maximum dose was 30 Gy in the center and 20 Gy in the margin of the tumor. Others: maximum 25 Gy margin 20 Gy). After radiosurgery, she had severe headache, nausea and vomiting and showed progression of aphasia. CT scan revealed a peritumoral hemorrhage. Conservative therapy was undertaken and the patient's symptoms improved. After 7 days, she was discharged, able to walk. The patient died of extensive distant metastasis 5 months after SRS. Acute transient swelling following conventional radiotherapy is a well-documented phenomenon. However, the present case indicates that such an occurrence is also possible in SRS. We have hypothesized that acute reactions such as brain swelling occur due to breakdown of the fragile vessels of the tumor or surrounding tissue.

Adult↗

PubMed2002

[The development of three dimensional video microscope system for clinical application in neurosurgery].

OBJECTIVE: The employment of surgical microscopy in the field of neurosurgery has significantly contributed not only to the advancement of surgical technique, but also the operative outcome as well. This technology has allowed surgeons to meet the demands for increasingly difficult levels of surgery, which usually require a long operative time. However, the surgeon and the assistant are restricted in their posture for a long time, leading to excessive muscular and ocular stress. To solve these problems, we have developed and clinically applied a three dimensional video microscope system for surgery, using a two binocular camera method, that allows surgical procedures to be performed over a video monitor. METHOD: Two 3CCD cameras were installed on the assistant's lens attachment and the camera lens attachment of the microscope for neurosurgery, manufactured by Carl Zeiss Co., Ltd. The surgery was performed by viewing the three dimensional picture on the monitor, which was created by processing the images from the cameras by a time-division method. In November 1998, the prototype was completed and, with numerous modifications, its clinical application has become possible. Currently, we have used it in 42 clinical cases. RESULTS: 1) Instead of viewing the surgical field through a conventional surgical microscope, the surgeon and the assistant were able to perform microsurgery by viewing the stereoscopic vision on the video monitor, through polarized glasses. 2) The assistant is provided with a separate video monitor, so that the assistant can freely adjust the angle of vision 90-180 degrees, according to where he stands. 3) The nurses, resident surgeons and students can view the same three dimensional images displayed to the surgeon. This effectively contributes to the educational environment. CONCLUSION: Even during a long surgical procedure, the posture of surgeon and assistant became less restricted since there was no need to look through the eyepiece of the microscope and led to significant decrease in physical fatigue and ocular strain. In the 42 clinical trials, the operation proceeded uneventfully, without any serious complications.

Brain Diseases↗

PubMed2002

[Predicting of the period of recurrent for a post-operative glioblastoma after radiochemotherapy using 201TlCl SPECT].

After radiochemotherapy for a post-operative glioblastoma multiforme (GB), the majority of patients return at a later date with a recurrent. To assess whether 201TlCl uptake can be used as a prognostic indicator in patients with GB, we measured the ratio of 201TlCl uptake in tumor to 201TlCl uptake in normal brain (TL index) in 10 patients at the end of radiochemotherapy and followed all the patients until they returned with a recurrent. The TL indices at the end of radiochemotherapy indicated 1.36 to 6.82 (mean +/- SD; 3.59 +/- 1.84), and the terms of tumor recurrent were 3-12 months (5.55 +/- 3.10 month). There was a significant negative correlation between the TL indices and the terms of tumor recurrent (y = -1.28x + 10.14, r = 0.760, p < 0.01). Especially, three cases indicated less than 2.0 did not returned with a recurrent in 8 months and 7 cases more than 2.0 returned with a recurrent in 5 months. This study resulted that 201TlCl SPECT was clinically useful to predict the period of recurrent for GB.

Adult↗

PubMedDate not supplied

Quantitative cerebral blood flow calculation method using white matter lambda in xenon CT.

The objective of this work is to propose a quantitative cerebral blood flow (CBF) calculation method for xenon CT (Xe-CT) by logically estimating the time course change rate (rate constant) of the arterial xenon concentration from that of end-tidal xenon concentration. A single factor, gamma (gamma), which is considered to reflect the diffusing capacity of the lung for xenon, was introduced to correlate the end-tidal rate constant (Kend-tidal) with the arterial rate constant (Karterial). When an appropriate value is given to gamma, it is possible to calculate the arterial rate constant (calculated Karterial) from Kend-tidal. A procedure was developed to determine the gamma value utilizing the characteristics of white matter lambda (lambda). This procedure was applied to three healthy volunteers. The gamma gammaalues for the three subjects were consistent with those directly calculated from end-tidal and arterial (abdominal aorta) xenon data. Hemispheric CBF values with use of calculated Karterial (47.3 +/- 10.3 ml/100 g/min) were close to the reported normative values. We conclude this method could make current Xe-CT examinations substantially reliable and quantitative in measuring CBF.

Adult↗