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Y Ishiwata

Publications and source records attributed to Y Ishiwata.

66 records · Page 4Linked to original sources
PubMed1987

[Subdural tension pneumocephalus following surgery of chronic subdural hematoma].

Subdural tension pneumocephalus (TP) following surgery for chronic subdural hematoma was analyzed in 5 cases from clinical standpoints of view, especially from CT findings. The cases were compared with 14 cases of subdural asymptomatic pneumocephalus (AP). The TP tends to complicate elderly patients who showed a poor re-expansion of the brain after irrigation of bilateral chronic subdural hematoma. In such patients, it is difficult to make an exact diagnosis of TP because of residual mass effect of the evacuated hematoma. Significance of mass effect caused by subdural air has been discussed in the literature only little. In this study, we found two new CT findings suggesting increased tension of subdural air. First, the subdural tensive air separates and compresses the frontal lobes. The compressed frontal lobes with widened interhemispheric space between the frontal poles mimic the silhouette of Mt. Fuji. We called this CT finding "Mt. Fuji" sign. The presence of air between the frontal poles associated with massive air over the frontal lobes presumably indicates an increased tension of the subdural air. "Mt. Fuji" sign was seen in 4 cases out of 5 TP cases. Another sign is the presence of multiple small air bubbles in the subarachnoid space, especially in the cisterns. We proposed that these air bubbles were trapped in the subarachnoid space through a tear of the arachnoid membrane which is caused by increased tension of air in the subdural space. This finding was present in 4 cases with TP. We emphasize that these two CT signs are helpful to make an accurate diagnosis of TP following surgery for chronic subdural hematoma.

Aged↗
PubMed1985

Thermosensitive determination of obstructed sites in ventriculoperitoneal shunts.

A simple method is described for checking the patency of ventriculoperitoneal shunts by using a pair of small disc thermistors. With this technique, shunt patency is shown by a downward deflection of the recording trace, blockage of the ventricular catheter is indicated by a flat-line recording, and obstruction of the distal end of the abdominal catheter is demonstrated by an upward deflection. These observations were confirmed in a study of 32 hydrocephalic patients with obstructed shunts who subsequently underwent shuntography and operation. An experimental model was also devised to study the mechanism of the recording changes.

Adult↗
PubMed1985

[Thrombosis of cortical vein: a case report].

A 39-year-old woman presented with disturbed consciousness, left hemiparesis and headache. CT scan revealed subcortical hemorrhage in the right parietal region, which had lower density than usual intracerebral hemorrhage and was associated with irregular perifocal edema. Cerebral angiograms revealed narrowed cortical vein with irregular wall in the right parietal region, where delayed local blood flow into the deep cerebral veins through collateral vessels was noted. The diagnosis was subcortical hemorrhage due to thrombosis of cortical vein. Her symptoms and brain edema were progressive. To reduce intracranial pressure, evacuation of the hematoma was performed. The hematoma which existed 1cm under the right parietal cortex was about 20g in weight. She remarkably improved soon after operation. Frequency of sinovenous thrombosis has been reported to be about 10% of all cerebral ischemic diseases, however, localized venous thrombosis is rare among them. This is because it is not always symptomatic and it is difficult to make accurate diagnosis. Six cases of localized venous thrombosis were reviewed, in which accurate diagnosis were established by cerebral angiograms, CT scan and/or autopsy. Clinical and radiological features of this case were presented.

Adult↗
PubMed1984

[Treatment of recurrent gliomas].

In operation for gliomas, it is our principle to remove extensively by sucker dissection technique. But, in many cases, we cannot achieve total removal because of invasion of tumor cells into the deep or vital structure. Postoperatively we apply irradiation, chemotherapy and immunotherapy in every cases. Even after multimodality treatment, recurrence may be inevitable. In order to check the recurrence as early as possible, we took follow-up CT scan regularly. When the recurrence appeared on CT scan, we actively performed reoperation. In this paper, we present characteristics of follow-up CT scan and result of the reoperation. Since introduction of CT scan in 1977, we have followed 30 supratentorial malignant gliomas and 16 supratentorial low grade gliomas postoperatively. CT scan was taken in every three months to check the course of contrast enhancement. After removal of the tumor, round low density area appeared on CT scan showing residual cavity. By contrast enhancement, various shape of high density area were seen. We divide the postoperative CT scan in 4 types by mode of contrast enhancement. In the type 1, enhanced area was persistent around the low density area. In the type 2, enhanced area was present around the low density area just after operation, but gradually disappeared. In the type 3, no enhanced area was present. In the type 4, dissemination occurring late after operation. Among the malignant gliomas, 12 cases belonged to the type 1, 6 cases to the type 2, 10 cases to the type 3, and 2 cases to the type 4. Among the low grade gliomas, 3 cases belonged to the type 1, 2 cases to the type 2, and 9 cases to the type 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Chemotherapy for experimental subarachnoid dissemination model of brain tumor].

Chemotherapy was applied for experimental subarachnoid dissemination model of brain tumor which was established in male Wister-SPF (SLC) rats inoculated intracisternally with 2 X 10(5) C6 rat glioma cells. Nontreated animals died about 24 days after inoculation. Autopsy findings of the animals showed localized or multifocal invasion of the tumor on leptomeninges in cisterna magna, and partially infiltration into the parenchyma of the cerebellum and medulla oblongata. Three days after inoculation, the tumor deposition and proliferation already occurred. Several tumor cell layers were found in the subarachnoid space over the cerebellomedullary surface. Tumor bearing animals were at first treated by single agent. These are ACNU administered intraperitoneally, methotrexate administered intracisternally, and OK-432 administered intraperitoneally. In the next stage, combination of these drugs was applied. ACNU, 3 mg/kg i. p., on Day 3, was effective in elongation of median survival time by 23.6%, statistically significant (P less than 0.02). Methotrexate, 0.25 mg/kg i.th., on Day 3, was also effective in elongation of median survival time by 8.4%, statistically significant (P less than 0.05). OK-432, 0.1 KE/kg i. p., daily, 14 times, from Day 3 to Day 16, was ineffective in elongation of median survival time. Combination of ACNU, methotrexate and OK-432, in the same schedule as described above, produced the longest median survival time of 42.4%, statistically significant (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗