Susumu Nakatani

Hemangioblastoma of the third ventricle.

Abstract A third ventricle tumor, in addition to a recurrent cerebellar hemangioblastoma, was found in a 47-year-old woman on follow-up magnetic resonance imaging (MRI) 5 years after operation of the cerebellar tumor. On MRI, the tumor was hypo- to isointense on T1-weighted images and hyperintense on T2-weighted images compared with the normal gray matter, and was strongly enhanced with gadolinium. The tumor was first treated with fractionated conventional external-beam radiation (5120 cGy in 16 fractions over a 4-week period), resulting in a slight decrease in size of the tumor. For a definite diagnosis and mass reduction, surgery was performed using an interhemispheric translamina terminalis approach, resulting in a partial removal of the tumor due to profuse bleeding. Histological diagnosis was hemangioblastoma. Hemangioblastomas of the third ventricle are extremely rare and have not been specifically discussed. We describe the detailed clinicopathological features of the present case together with the possible explanation for the development of this tumor in this rare location.

Direct ethanol injection for skull metastasis from hepatocellular carcinoma. The techniques and consequences of a therapeutic trial

The frequency of skull metastasis from hepatocellular carcinoma (HCC) is increasing together with the recent progress in the management of the primary lesion. Cases are often complicated with poor general conditions or metastasis to the other organs, and not readily indicated for surgery. A direct injection of ethanol to the lesion could be one of the therapeutic options to cope with this complicated situation. To evaluate the feasibility of this technique, we planned a therapeutic trial in a patient with HCC associated with lumbar and skull metastasis, the latter metastasis repeated twice during the past one year. A total of 10 ml of ethanol was injected into the skull metastasis percutaneously under ultrasound (US) guidance. US guidance was very useful in determining the sites of injections and the distribution of ethanol as well as monitoring the blood flow within the tumor vessels. The patient transiently complained of local pain at the injection sites, but there were no other adverse effects. Four days after the injection, the lesion was resected by surgery, which confirmed the pathologic diagnosis as well as the nearly-total necrosis of the tumor. This technique is simple, safe and repeatable with low cost. The technical details and the histologic effects are described.

Detection of the B waves in the oscillation of intracranial pressure by fast Fourier transform

Intracranial pressure (ICP) oscillation consists of a cardiac-induced component, a respiration-induced component and fluctuation of the base level of ICP. Lundberg reported three types of fluctuations of the base level of ICP with increasing ICP which were referred to as A, B and C waves. Computer algorithms for sampling, processing and displaying ICP data were investigated to depict the power spectrum of ICP oscillations by fast Fourier transform (FFT), thus enabling the B wave to be automatically detected. A power peak was found in the ICP power spectrum between 30 and 120 s, which corresponds to the frequency of the B wave. The maximum power, corresponding to the B-wave amplitude was above 0 dB. An appropriate sampling interval for FFT inputs was about 8 s for real-time processing of the ICP data. The mean ICP value was found useful for making the B-wave peak clearer by reducing the cardiac and respiratory components of ICP oscillations; the window function had no effect on B-wave detection in the ICP power spectrum.

Simultaneous Monitoring of ICP and Transcranial Doppler Sonogram on the Middle Cerebral Artery

It has been pointed out that an absolute value of ICP alone, although important, does not provide enough information about the on-going critical changes of intracranial hemodynamics. Using transcranial Doppler it is possible to record blood flow velocities (FV) of basal arteries of the brain allowing us to monitor the hemodynamic changes instantaneously (Aaslid et al. 1982). We assessed the correlation between ICP and FV to investigate a noninvasive measure of intracranial pathology.

A Minicomputer System for Analysis and Display of ICP Related Data

It has been suggested that analog data recording of ICP on paper does not provide enough information on the real condition of the patient, making further data processing impossible. Several microcomputer systems have been reported recently, that deal only with fragmental portions of the intracranial pressure dynamics. With a minicomputer we developed a total system of comprehensible color graphic display and digital printing of ICP related data, creating a new technique and improving the algorithms of sampling and analysis already reported.

Prediction of ICP and Pressure Wave Discrimination with Our Intelligent Monitor System (IMNIC-1)

The clinical importance of continuous monitoring of ICP with other polygraphic data for intensive care of neurosurgical cases is already well-known. Successful feed-back of these polygraphic data for automated control of critically ill cases was reported in other fields (4, 5). There are few reports on the trials of automated control of ICP by signals from a continuous monitor (3), since the theoretical basis of pathophysiological mechanism of ICP is not yet well-established in spite of a numerous reports on clinical and experimental analysis of ICP.

Huge Epithelium-lined Cyst in Infancy

An infant case of huge epithelium-lined cyst in the posterior fossa is reported. The cyst was located in the prepontine region of the posterior fossa with extension to the bilateral middle cranial fossae, through the tentorial incisura. It had no communication with the ventricular system or subarachnoid space. The cyst wall was lined with ciliated columnar and cuboidal epithelial cells which were completely invested by a basement membrane. The diagnosis and the management of such cases were discussed and the pathogenesis of the cyst was reviewed.

Somatosensory evoked potentials to median nerve stimulation after partial section of the corpus callosum.

SummaryCortical somatosensory evoked potentials (SEPs) to electrical stimulation of the median nerve were studied in four patients with intractable epilepsy who had undergone callosotomy and in a patient with infarction in the corpus callosum in order to determine whether the corpus callosum was involved in the generation of ipsilateral frontal components. Both pre- and postoperative SEPs were recorded in three of four epileptic patients. There were no significant differences in the latencies and amplitudes of the bilateral frontal components (P20, N26) between pre- and postoperative recordings. Furthermore, irrespective of the extent of the section or lesion in the corpus callosum, the nature of the impairment and the existence of the disconnection syndrome, the SEP findings showed no significant differences compared with those of normal subjects. It thus appears unlikely that the ipsilateral SEP responses are transmitted from the contralateral hemisphere through at least the anterior portion of the corpus callosum.

Paradoxical Effects of Barbiturates on ICP. Acutely Increased by Cold Induced Edema in Cats

Recently, barbiturates have been widely used in clinical situations. Experimental and clinical evidence seems to support the effectiveness of these substances in reducing intracranial pressure (ICP) (Ishii 1966, Rockoff and Marshall 1979, Clubb et al. 1980, Bricolo and Glick 1981). However, in our clinical experience of high-dose barbiturate therapy a rebound rise and a pressure wave-like fluctuation of ICP are not infrequent. There are no established guide-lines for the administration of the drug. We therefore carried out an extensive experimental study on the timing, dose and mode of administration of barbiturates.

Intracranial Volume and Pressure Load Tolerance Evaluated by Continuous Measurement of Doppler Flow Velocity in Intracranial Vessels in Cats

In order to study the noninvasive evaluation of intracranial hemodynamics during intracranial hypertension a technique employing pulsed Doppler ultrasound (MF-20 microvascular Doppler, EME) was developed to measure blood flow velocity in the basal arteries of cats. Flow tolerance to volume and pressure loading was assessed by changes in the Doppler flow velocity and wave form.