Biomedical subjects
Publications and source records attributed to H Imanaga.
From printout data of 50 normal and 50 abnormal scans of a brain slice picking up the basal ganglia the numerical values of SD and DC were obtained and those values lying inside M + 2sigma were arbitrarily regarded as normal. By these criteria two cases (4%) were diagnosed as false negative and three cases (6%) as false positive, with a misdiagnosis rate of 5%.
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Asymptomatic transient hyperamylasemia accompanied with hyperamylasuria immediately after an intravenous dose of 1 gm methylprednisolone has been observed in renal homotransplantation patients. Similar phenomena have also been seen in the other operative patients who received certain amounts of steroid hormone intravenously during their procedure. These cases of hyperamylasemia and hyperamylasuria were studied in detail including time-sequence observation, amylase-creatinine clearance ratio, and amylase isoenzyme analysis. The hyperamylasemia is not due to the general anesthesia or the surgical procedure. It is apparently not due to simple retention of enzyme from poor kidney function. The source of hyperamylasemia is the pancreas mediated by large intravenous doses of steroid hormone.
This study was aimed to investigate the correlation between recurrent hemorrhage of ruptured intracranial aneurysm and local fibrinolytic activity of aneurysmal fibrin plug. The fibrinolytic activity of cerebrospinal fluid (CSF) was investigated in 63 patients with various neurological diseases by means of modified fibrin plate method. No plasmin was elicited in normal CSF, however, it was confirmed that CSF contained an incomplete activator which became a complete activator inthe presence of streptokinase, and plasminogen was identified in the presence of urokinase. In 26 cases of subarachnoid hemorrhage, the fibrinolytic activity of CSF occurred in the patients within two weeks following hemorrhagic ictus. In almost cases, the fibrinolytic activity of CSF was not increased in the first three weeks after the onset of hemorrhage. This result agreed with the fact that rebleeding of intracranial aneurysm tended to occur within two weeks after the hemorrhage. Therefore, intensive antifibrinolytic therapy for two weeks after onset of hemorrhage is necessary in order to prevent recurrent hemorrhage of intracranial aneurysm, and its doses should be sufficient to inhibit local fibinolysis. It has been suggested that the local fibrinolysis after subarachnoid hemorrhage would be caused by activators released from damaged surrounding brain tissues. Furthermore, it is strongly suggested from the result of our in vitro experiments that coexistence of CSF and blood play an important role to increase local fibrinolysis.
Computerized transverse axial tomography (CT) of the brain is a recently developed method which allows non-invasive roentgenologic evaluation of intracranial diseases. The advent of CT represents a great advance in the diagnosis of a very wide variety of intracranial lesions, including cerebrovascular diseases. Especially, CT was found to be extremely informative in evaluating intracerebral, intracerebellar and intraventricular hemorrhage. The purpose of this report is to evaluate the clinical usefulness of CT in the diagnosis of intracranial hemorrhage. From the seven hundreds cases of various intracranial diseases hitherto examined by the EMI-scanner (160 X 160 matrix), twenty-three cases of nontraumatic intracranial hemorrhage were selected for the present study. Fifteen cases of fresh hemorrhage consisted of hypertensive cerebrovascular disease, arterio-venous malformation, aneurysm and unknown etiology, number of cases being six, three, four and two, respectively. All cases were examined within fifteen days after the ictus and the positive findings were obtained in all cases. The characteristic feature of the hematoma is the circumscribed and increased density area surrounded by the decreased density zone probably representing the accompanied brain edema. The sequential CT studies revealed that the hematoma area was gradually decreased in its density and finally transformed into the rather low density one in four weeks or so after the ictus. The smallest hematoma detected by CT was the cerebellar hematoma about five grams in weight, which was failed to be recognized by the angiography. In cases of the old hemorrhage, besides the decreased density area of the hematoma, such findings were obtained as cerebral atrophy, ventricular dilatation and porencephalic change. It would be concluded that CT study is the most useful aid at present available in the diagnosis of intracranial hemorrhage. The precise anatomic extent of the hematoma, associated brain edema, ventricular deformity and displacement and hydrocephalus are all readily assessed by CT.
The purpose of this study is to investigate salient diagnostic features of the brain abscess in RI brain scanning. In 27 patients with brain abscess, 37 scannings were performed in the various stages of their clinical courses. The results were positive in all cases. Among 27 cases, ten cases were investigated by means of the ISOCOUNT SCANNING SYSTEM, the technical detail of which was reported previously. It was proved that the isocount scanning method combined with the multilevel analysis was more sensitive diagnostic aid than the conventional RI scintigraphy. Using the newly developed method, it was not difficult to diagnose the brain abscess in its early stage, even in the stage of presuppurative cerebritis. Doughnut sign was seemed to be more frequently visualized by this method. Surgical indication of the brain abscess was discussed from nucleomedical view point, and it was emphasized that so-called doughnut sign in brain scanning would indicate the appropriate stage of the brain abscess to be operated on.
In the previous reports, the theoretical background [corrected] and technical details of the Isocount scanning were described. Based on clinical experiences of various brain diseases, the newly developed scanning method was confirmed to be more useful than the conventional scintiscanning. Besides the new scanning method, a new display system was also developed for the sake of more precise analysis of the Isocount scanned data. This display method is called MULTILEVEL ANALYSIS or MULTILEVEL SLICING. In the present investigation, this method was applied to fortysix cases of brain tumors, including forty cases of supratentorial tumors and six cases of infratentorial tumors, positive rates being 95% and 67% respectively. Furthermore, as a measure of the quantitative investigation of the radioactive tracer uptake of the target area, the maximum uptake rate of the target area (RTmax.=Tmax./NTmean), and the deviation index (DI=DT/DNT) were introduced; Tmax., NTmean, DT and DNT are respectively defined as a maximum uptake of the target area, a mean uptake of the non-target area, a deviation rate of the target area and a deviation rate of the non-target area. They can be obtained from analysing the television figures of MULTILEVEL ANALYSIS. By this method, thirty-four cases of supratentorial tumors were studied. In cases of glioma (12 scans), meningioma (9 scans), and metastatic tumor (7 scans), the mean values of RTmax. were 1.26, 1.37, and 1.24 and the mean values of DI were 0.81, 0.68 and 0.60 respectively. In gliomas, the RTmax. and the DI were correlated with the degree of malignancy of the tumors. This quantitative analysis could be considered to be useful to foresee the nature of the brain tumor from the scintiscanning findings.
Hyperosmolar nonketotic coma is characterized by hyperglycemia, hyperosmolarity and dehydration in the absence of ketoacidosis. Two cases of hyperosmolar nonketotic coma, in which both the patients recovered, were presented. One of the cases was a 59-year-old female who had suffered from a metastatic brain tumor. After removal of the tumor, the patient's condition improved for a period. This was followed by a period of frequent vomiting, subsequently followed by coma. The laboratory data showed the absence of ketoacidosis in the blood sugar measured at 672 mg/dl and serum osmolarity at 343.1 mOsm./kg. The other case was a 74-year-old female who was admitted to the clinic because of cerebral thrombosis. Her caloric in-take was restricted and insulin was administered because of a mild diabetes mellitus which occured after admission. Then she entered a hyperosmolar non-ketotic coma. The laboratory data revealed blood sugar to be 1068 mg/dl and serum osmolarity to be 418 mOsm./kg. Immediately after large amounts of intravenous drip infusion and insulin were administerd, she recovered from the syndrome. The clinical observations and the pathogenesis of this syndrome were discussed.
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Selective celiac and superior mesenteric arteriographies were performed in patients with portal hypertension. An arterioarterial (A-A) shunt between the superior mesenteric artery and the celiac axis via pancreatic arcades was found in fifteen of forty-three patients with associated massive splenomegaly. A mild A-A shunt disappeared after portacaval anastomosis alone, whereas a prominent A-A shunt was reduced but persisted. The persisting A-A shunt disappeared after splenectomy. These findings led us to suggest that the paucity of the blood flow in the common hepatic artery concomitant with increased splenic arterial flow to the massively enlarged spleen may result in a compensatory supply to the liver from the superior mesenteric artery via the shunt.
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In the previous report the theoretical background and technical details of the isocount scanning were described. Based on clinical experiences of various brain diseases, the newly developed scanning method was confirmed to be more useful than the conventional scintiscanning. Besides the new scanning method, a new display system was also developed for the sake of more precise analysis of the isocount scanned data. This display method is called multilevel analysis or multilevel slicing of the scanned data. In the present investigation, this method was applied to thirty-two cases of cerebrovascular diseases, including seven cases of cerebral arterio-venous malformation, four cases of hypertensive intracerebral hemorrhage and twenty-one cases of cerebral infarction, positive rates being 86%, 100% and 90% respectively. In case of arterio-venous malformation, minimum size detected by the isocount method was 2 cm in diameter. To twenty one cases of the cerebral infarction, total thirty two scanning examinations were performed, including postictal follow up studies. It is often said that it is two or three weeks after the ictus when the infarcted cerebral lesion is most clearly detectable by the scintigraphic procedures, presumably due to focal neovascularizations which may occur in the lesion most prominently at this postictal stage. Contradicted to the current concept, our experiences show that abnormal dot accumulations are recognized in the scintigrams even at the earlier stage, thus among five cases of cerebral infarction scanned within a week after the ictus positive figures were obtained in four cases, two of which were examined within two days after the ictus. Focal breakdown of blood brain barrier at the acute stage is considered to be responsible for the early positivity in cerebral infarctions. In eight cases among twenty one cerebral infarctions angiographies failed to demonstrate the vessel occluded. The isocount scanning method, however, succeeded in getting positive results in seven of the eight cases. It will be emphasized that the isocount scanning is a preferable diagnostic procedure in the cerebrovascular diseases, especially when the angiography is hesitated to be performed because of the patient severely affected.
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It is well known that the gamma ray emitted by a radionuclide is a Poisson process, so its statistic nature should be taken in consideration when the scintiscanning is performed. But very few attempts have been done from this point of view. After examining in detail the imaging pulse charactristics, the authors introduced a mean for evaluating the fidelity of the collected data, and based on this criterion, pointed out some problems in the conventional scanning method and finally described a statistical way of improving the scintigram. In the present investigation, as a measure of the stochastic fidelity of the scanned data the relative deviation eplision(n) = sigma(n)/E(n) is introduced; sigma is the standard deviation and E(n) is the expectation value of the counting rate. In the conventional scanning in which the detector moves with a costant speed, the relative deviation varies from area to area according to the concentration of the radioisotope in the brain. In the so-called cold area of the brain scintigram, the relative deviation fluctuates remarkably because of a rather low density of radioisotope in this area.
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