A cranial cavity with its contents was modeled as an unknown system and the technique of systems analysis was applied to it. The carotid arterial pulse wave was employed as the input and the epidural pulse wave as the output. The relationship between input and output was shown as the transfer function that contains all physical features of the system. Fifteen adult mongrel dogs were divided into three groups, and subjected to the following experimental conditions: intracranial hypertension by epidural balloon inflation (Group 1), intracranial hypertension by saline infusion into the cisterna magna (Group 2), and hypercapnia by decreasing the tidal volume (Group 3). The carotid arterial and epidural pulse waves were simultaneously recorded under resting intracranial pressure and each experimental condition. The data were analyzed using a computer program developed in the laboratory. The transfer functions were plotted on Bode diagrams. The transfer function under resting intracranial pressure showed resonance, that is, the gain curve formed a sharp peak within the range of 10 to 15 Hz and the phase shift curve changed from positive to negative within the same frequency range. In Groups 1 and 2, however, the sharp peak of the gain curve under resting pressure became increasingly obscure as intracranial pressure rose. This phenomenon occurs with intracranial hypertension because the gain is already high in the lower frequencies (less than 10 Hz) while unchanged in the resonant frequency. Changes in the transfer functions could not be distinguished between Group 1 and Group 2. In Group 3, the gain also became high in the lower frequencies and the resonance was obscure. However, at less than 10 Hz the gain curve was flatter than those of Groups 1 and 2, and the phase shift at less than 10 Hz was near zero. This study indicates that resonance gradually disappears with intracranial hypertension and hypercapnia. But it is supposed that this is apparent disappearance, because a peak within the range of 10 to 15 Hz still exists under severe intracranial hypertension and hypercapnia.

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This study was carried out to clarify the biochemical changes in the cold injured brain and their relationship to pathological changes. The cold lesion was produced by application of a cryoprobe containing liquid nitrogen to the exposed left temporal surface for 1 minute in rats anesthetized with a halothane and oxygen gas mixture. The brain edema developed by this procedure was localized in one hemisphere. The animals were guillotined at scheduled times after the cold injury. The brains were rapidly removed and divided exactly between the two hemispheres. Changes in specific gravity of the brain tissue were measured by the dry-weight method until 4 weeks after the injury. Hematoxylin-eosin and Kliiver-Barrera stains were applied to pathological specimens. Free amino acid and uric acid levels were measured chronologically by using Iriyama's method. Catecholamine levels were analyzed by using high-performance liquid chromatography with electrochemical detection. Water content in the injured hemisphere reached a peak level at 12 hours after the injury, then decreased gradually, and entered the normal range at 1 week after the injury. This results was similar to the previous report. Multiple small hemorrhagic lesions were disclosed 2 hours after the injury. This suggests that a mechanism similar to hemorrhagic infarction might play a role in the development of cold injury. Essential amino acids were increased in the injured hemisphere, while those in the contralateral side remained within normal ranges. This result suggests that, in the injured hemisphere, there was not only nonutilization of the essential amino acids but also disturbance of the blood brain barrier, and that the aerobic glycolytic pathway was maintained normally in the contralateral hemisphere. Norepinephrine and dopamine were lowered, while tyrosine was increased in the early stage of cold injury. This suggests impairment of the catecholamine synthesis followed by nonutilization of catecholamine precursors. Uric acid level was increased immediately after the injury, especially on the injured side, and lowered to near baseline level at 4 weeks after the insult. Although biosynthesis of uric acid in the brain is not fully understood, it seems to be a fine parameter of brain damage.

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Calcium-antagonist (nicardipine, 0.1 mg/kg), barbiturate (thiamylal, 100 mg/kg), and saline as control were intraperitoneally administered to mongolian gerbils prior to the 20 minutes of ischemia, produced by bilateral clipping of the common carotid arteries of the animals. (1) The survival rates at either 24 hours or 14 days of recirculation of the animals, pretreated with nicardipine (n = 30) and thiamylal (n = 44), respectively, were significantly higher than that of control (n =64) (p < 0.05). (2) The changes in cerebral concentrations of adenosine triphosphate (ATP), phosphocreatine (P-Cr), glucose, lactate, and cyclic-adenosine 3'5'-monophosphate (C-AMP) were assayed during ischemia, and at various periods of recirculation after ischemia. During ischemia, accumulation of lactate and decreased concentration of the energy metabolites were similarly found in control and experimental animals with premedication. As early as 5 minutes after beginning recirculation, however, ATP and P-Cr increased up to 75% and 98% of control values, respectively, in the animals treated by nicardipine, whereas recovery of the controls and thiamylal-treated animals was not significant. At 30 minutes of recirculation in the control animals, the energy metabolites were restored as high as the control level, but two fold or more reaccumulation of lactate and significant decrease in ATP concentration occurred at 360 minutes of recirculation. In both groups of experimental animals with premedication, however, there were neither accumulation of lactate nor decrease of ATP concentration at 360 minutes. At the same time, the high energy phosphate utilization rate in both experimental groups measured in various periods of recirculation was found to be decreased compared to that of control groups. (3) Overshoot of C-AMP at 5 minutes of recirculation was found in all animals treated with or without premedication but the rate of the overshoot in thiamylal-treated animals was significantly lower than those of others. It seems that both calciumantagonist and barbiturate similarly demonstrate protective effects possibly by decreasing the energy demand of the brain during ischemia-recirculation periods. When compared with the effects of barbiturate during early periods of recirculation, calcium-antagonist appears to facilitate the rapid recovery of ATP and P-Cr regeneration, which are the indicators of mitochondrial activities. The physiological significance of relevant changes in C-AMP overshoot during early periods of recirculation, however, is not clearly understood.

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The effect of tranilast, an anti-releasing drug for slow reacting substance (SRS) on incomplete ischemia produced by a bilateral common carotid artery occlusion/recirculation model in the spontaneous hypertensive rat (SHR-SR) was investigated. Na⁺-K⁺ adenosinetriphosphatase (ATPase) activity in brain microvessels and brain parenchyma were measured separately. Na⁺-K⁺ ATPase activity in the microvessels was not influenced by tranilast treatment. Brain parenchymal Na⁺-K⁺ ATPase activity decreased progressively after recirculation. At 3 hours after recirculation, parenchymal Na⁺-K⁺ ATPase activity returned to the control level when treated by tranilast, and progressive decrease was observed in SHR-SR without tranilast treatment. Data suggest that the SRS produced in the brain parenchyma during ischemic insult was very important for production of brain edema. Tranilast might be very useful for the treatment of ischemic brain edema.

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Local cerebral glucose utilization (LCGU) was studied in 23 awake rats following fluid percussion injury (cerebral contusion). In this system, percussion energy was created by a hammer hitting a vinyl chloride membrane with thickness of 0.5 mm and diameter of 100 mm. This system produced a biphasic impact, which would do no unfavorable damage to the brain stem, but cause a reproducible localized cerebral contusion. The LCGU was quantitatively measured by the [¹⁴C]deoxyglucose autoradiographic method (Sokoloff). Six rats were controls. LCGU was studied at 1, 2, 4, and 24 hours following injury. [¹⁴C]deoxyglucose uptake was remarkably decreased at the center of the contusion and LCGU was mildly decreased at 1 and 4 hours, and definitely at 24 hours over the ipsilateral hemisphere. Interestingly there were two different types of behavior in LCGU changes at 2 hours after injury; no change or slight decrease in 4 of 6 rats (Group A) and remarkable increase (more than 150%) all over the cortex and the hippocampus of the ipsilateral side in 2 of 6 rats (Group B). This unique phenomenon in Group B—“hypermetabolic state”—resembles the autoradiographic findings in cortical spreading depression, which reportedly show remarkable increase of extracellular K⁺ and negative shift of direct current (DC) potential, associated with increased glucose uptake of the brain. Persistent oligemia was also reported following cortical spreading depression. The authors observed negative shift of DC potential between 1 and 4 hours, most frequently around 2 hours, after fluid percussion injury (unpublished data). If this hypermetabolic state following experimental head injury is associated with persistent oligemia, as reported in cortical spreading depression, cerebral metabolism would be trapped in a vicious cycle. Secondary brain damage is quite possible due to the above reason, and 2 hours after injury would be the critical period for any trial of treatment.

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Temporary intravascular occlusion of experimental aneurysms by hollow-centered balloon (HCB) catheter permitting blood flow through the main artery was studied in six canines. Of six experimental aneurysms of cervical arteries, which were made by the ligation of external carotid arteries, four aneurysms were thrombosed by HCB for 30 minutes to 120 minutes. The remaining two did not get thrombosed. One of the thrombosed aneurysms, which was occluded by HCB for 120 minutes, showed a complete occlusion of the cervical carotid artery. However, in the rest of the aneurysms, the internal carotid arteries were well demonstrated through HCB on angiograms. Due to occlusion by HCB the lumen of the internal carotid arteries was found dilated, and the endothelial cell layer was histologically compressed.
HCB might be applied for clinical trial for inaccessible intracranial aneurysms, especially for giant aneurysms in the cavernous portion of the internal carotid artery, although further improvement of HCB is needed to be able to introduce it into the intracranial vessels without difficulty.

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A computerized monitoring and analyzing system for neurosurgical intensive care was developed. In this system, information concerning not only the central nervous system but also the cardiovascular and respiratory systems can be monitored continuously, and the correlations among the parameters can be analyzed automatically. Electroencephalograms (EEG) and intracranial pressure (ICP) are monitored as parameters for the central nervous system function and condition. EEG is analyzed by fast Fourier transform or wave-form recognition method, and power, percentage time or mean amplitude of each frequency band is computed sequentially. ICP is recorded from a catheter placed in the lateral ventricle, in the spinal subarachnoid space or from a transducer in the epidural space. The cardiovascular and respiratory systems are monitored by heart rate, systemic blood pressure, central venous pressure, pulmonary arterial pressure, respiratory rate, expiratory O₂ pressure, and CO₂ pressure. Body temperature is also monitored continuously. On the other hand, off-line recorded data such as cardiac output, blood gas analysis, serum electrolytes and so on can be entered in this system manually. Sequential changes of those parameters are displayed as time-dependent trend graphs, and the correlations among the various parameters can be analyzed by the equation of regression automatically. From the time-dependent trend graph, changes of functional and supporting systems of the brain as well as systemic and metabolic parameters can be observed easily, and a tendency for the worse can be monitored. From the results of the correlation analysis, pathophysiological dynamics can be considered and a suitable treatment should be selected.

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Three dimensional tomographic images of local cerebral blood flow (1CBF) using single photon emission computed tomography (SPELT) were obtained with N-isopropyl-p-[¹²³I]iodoamphetamine (¹²³I-IMP) and ¹³³Xe in 19 subjects: seven with ruptured aneurysm, one with unruptured giant aneurysm, five with arteriovenous malformation (AVM), six with moyamoya disease. This study concerned a comparison between the two methods of ¹³³Xe inhalation and ¹²³I-IMP intravenous injection. Clinical and morphological (angiography, CT scan) findings were used for reference.
The SPECT image showed low 1CBF earlier and larger than CT scan abnormalities in patients with cerebral vasospasm following subarachnoid hemorrhage. ¹³³Xe 1CBF images showed high flow areas in giant aneurysm and nidus of AVM but ¹²³I-IMP SPECT showed decreased activity in these areas. Low activity area with ¹²³I-IMP around the large AVM may indicate an intracerebral steal phenomenon or decreased metabolism. In the patients with moyamoya disease, CT scan demonstrated minimal changes, but large areas of decreased 1CBF were demonstrated with both ¹³³Xe and ¹²³I-IMP. The patients with intracerebral hematoma had a definite defect area of 1CBF corresponding to the hematoma on CT scan and a large area of decreased activity around the hematoma.
¹³³Xe ICBF and ¹²³I-IMP SPECT maps correspond well with each other under certain conditions, but they differed in the points of spatial resolution and true nutritional blood flow. ¹²³I-IMP may give an image of other functions more important than cerebral blood flow.

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Twelve cases of spinal extramedullary arteriovenous malformation (AVM) were studied clinically and radiologically. They were classified into four types: premedullary type, retromedullary type, AVM in the conus region, and radiculomeningeal type. In the premedullary type, an arteriovenous fistula (AVF) rather than nidus existed between the anterior spinal artery and vein. Similarly, a fistula rather than nidus was found between the posterior spinal artery and vein in the retromedullary type. AVM in the conus region was intradural extramedullary around the conus medullaris. Radiculomeningeal AVM or AVF has been considered as the “single-coiled” type of spinal cord AVM. The nidus or fistula in this type fed by branches of the dorso-spinal artery existed around the intervertebral foramen, and was drained reversely through the radiculomedullary vein into the posterior spinal venous system. In all types of extramedullary AVM, congestion of the spinal venous system contributed as a pathogenetic mechanism. Vascular steal, mass effect, or adhesive arachnoiditis were also important pathogenetic factors. Artificial embolization was the treatment of first choice in principle. However, operative indication existed not infrequently according to the type or the site of AVM such as radiculomeningeal type.

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Thirty-eight cases of brain abscess observed from 1959 to 1983 were analyzed. Thirty-seven cases were operated on and 22 cases out of these were treated with aspiration, 14 cases with extra-capsular total excision, and one case with ventricular drainage. The operative mortality and morbidity were compared between the aspiration group and the excision group. Total surgical mortality rate was 14%. The surgical mortality rate of the aspiration group was 17% and that of the excision group was 7%. Severe consciousness disturbance was observed preoperatively in approximately 30% of the aspiration group. Surgical morbidity of the aspiration group was more favorable than that of the excision group. Postoperative convulsion was observed in 21% of the aspiration group and 15% of the excision group. Recurrence of abscess was observed in only one patient, who had malignant lymphoma. Brain abscess is considered to be cured by aspiration, appropriate chemotherapy and control of intracranial pressure. Extra-capsular total excision is unnecessary except in cases such as those resisting repeated aspiration.

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Four cases of symptomatic metastatic pituitary tumors are presented and the pertinent literature on the management of secondary tumors of the pituitary region is reviewed. Of the 4 cases, 2 had metastases from breast carcinoma, one had pituitary metastasis from liposarcoma of the leg, and one had direct invasion of nasopharyngeal squamous cell carcinoma to the clival and pituitary region. Two cases presented panhypopituitarism and in all cases rapidly deteriorating cranial nerve palsies were noticed. Contrast-enhanced computerized tomography scan precisely demonstrated the pituitary metastatic lesions in all cases. Transsphenoidal microsurgical tumor resections were performed in 3 cases. Visual disturbance observed in one was markedly improved after surgery. Cranial nerve palsies subsided completely in all cases after radiotherapy.
Metastases of malignant tumors to the pituitary region are not uncommon in postmortem examinations or in cases with hypophysectomy performed to treat advanced breast carcinoma. However, the majority of metastatic pituitary tumors are asymptomatic. Recently some authors reported a few cases which presented diabetes insipidus, anterior pituitary insufficiency or cranial nerve palsies as observed in these cases. In such cases, early recognition and radiotherapy will significantly improve the prognosis. When the cases has single metastasis or breast carcinoma metastasis, or presents visual field defect, transsphenoidal tumor resection is also assumed to be an effective treatment.

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A 48-year-old, right-handed female patient presented tonic generalized seizures followed by left parietal syndrome. At the initial angiography, a filling defect was noted in the proximal segment of the left posterior parietal artery. This arterial narrowing had disappeared and migrated distally at the repeat angiography 16 days later. Histologic examination of the occluded artery found cotton fiber emboli. Cotton fiber embolization during cerebral angiography is a recognized but rather rare complication, 18 such cases having been reported. Pertinent literature on this complication of angiography is reviewed and the mechanism and prevention of such an event are briefly discussed.

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A case of bilateral traumatic carotid-cavernous fistulas (CCFs) is reported. A 39-year-old man had fractures in the skull base and facial bones from a traffic accident. Several days later he had a pulsating proptosis, chemosis, and bruit in both eyes. Neurological examination on admission revealed right-sided blindness due to optic nerve injury. Cerebral angiograms demonstrated bilateral traumatic CCFs with large openings, and steal phenomenon of blood flow. Endarterial balloon catheterization with iodine contrast material was performed twice on the right side and once on the left side but failed. Subsequently the patient suffered from right retro-orbital pain and left blurred vision. A big venous pouch (or false aneurysm) occurred in the cavernous portion of the right carotid artery. The left CCF remained open with venous drainage to the cavernous sinus and superior ophthalmic vein, which resulted in left retinal congestive bleeding. The right venous pouch was treated by occlusion of the internal carotid artery with detachable balloons and external carotid artery to middle cerebral artery bypass with venous graft. The left CCF was treated again by detachable balloon with preservation of the internal carotid artery flow. Postoperative digital subtraction angiography revealed disappearance of bilateral CCFs. Problems of detachable balloon catheterization are discussed.

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Two cases of massive intracerebral hemorrhage associated with meningioma are presented. The patients were admitted with apoplectic onset of sudden headache and deterioration of consciousness. Plain and enhanced computed tomography scans showed the presence of a tumor attached to the falx and a massive intracerebral hematoma adjacent to the tumor in each patient. In one of the cases angiography coincidently demonstrated a left internal carotid-posterior communicating aneurysm. Total removal of the tumor and evacuation of the hematoma were undertaken in the two cases, and clipping of the aneurysm was concomitantly performed in one of the cases. Histologically, these tumors were meningotheliomatous meningioma and transitional one. The postoperative course was uneventful. These patients were discharged in excellent condition. Hemorrhage from meningioma and meningioma associated with aneurysm are discussed.

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A case of massive epistaxis due to a traumatic aneurysm of the internal carotid artery associated with an asymptomatic carotid-cavernous fistula is reported. Because of early opacification and engorgement of the cavernous sinus caused by the fistula, the traumatic aneurysm was overlooked and treatment was delayed. The lesions were treated by embolization of the fistula using a detachable balloon catheter and trapping of the internal carotid artery. The association of traumatic aneurysm and carotid-cavernous fistula is discussed and the relevant literature is reviewed.

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