Koji Ozaki

Fahr’s Disease Associated with Cystic Astrocytoma

The authors present a case of Fahr’s disease associated with a cystic astrocytoma. This is the first patient with both entities to be reported.

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.

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.

Combined Common Carotid Ligation and Axillary-middle Cerebral Artery Interposed Long Saphenous Vein Bypass Graft for Treatment of Unclippable Giant Internal Carotid Aneurysm

Recently combined ligation of ICA and STA-MCA anastomosis has become the treatment of choice for unclippable giant aneurysms of the ICA . However, ischemic complications have been reported in 10-25% of the cases that underwent this procedure, because of the limited flow provided by the STA-MCA bypass and of thrombo-embolic ischemia originating from the stump of the occluded ICA and thrombosing aneurysm. An interposed long saphenous vein bypass graft was utilized between the axillary artery and the angular branch of the middle cerebral artery instead of STA-MCA anastomosis to treat a patient with an unclippable giant aneurysm of the cavernous portion of the right ICA combined with acute ligation of CCA. Ten minute manual compression of the right CCA developed neither abnormality of EEG nor ischemic symptoms. Angiography also demonstrated a good cross-filling of the ipsilateral carotid region. However, a SPECT subtraction study revealed 70% reduction of flow in the ipsilateral MCA region by manual compression of the right carotid artery. Intraoperative measurement of the flow through the vein graft was 80 ml/min. CCA ligated acutely on the third postoperative day after the patency of the vein graft bypass was assured . A postoperative angiogram revealed that the giant aneurysm was thrombosed successfully . There was a good filling of the left MCA territory through the graft and ACA through the anterior communicating artery from the contralateral circulation. Thus the ICA giant aneurysm was isolated, trapped and thrombosed . The postoperative SPECT study revealed a normal CBF at rest in both hemispheres . By compressing the vein graft bypass, 60% reduction of CBF in the MCA territory was demonstrated in the subtraction image of the SPECT. A three year follow-up revealed good patency of the vein graft with no ischemic symptoms. Acute ligation of CCA provides less chance of emboly, and a vein graft bypass from the axillary artery can provide an immediate postoperative high flow without carrying thrombi from the ICA stump. The giant aneurysm of the intracranial ICA is isolated from ipsilateral cerebral circulation . Thus, both hemodynamic and thrombo-embolic ischemia can be avoided. Kevwords: