[Intracranial pressure increase and changes in cerebrovascular circulation, associated with brain death, studied by transcranial Doppler sonography]

Blood flow velocity of 24 patients in state of the brain death were examined by transcranial Doppler sonography. Authors expound the characteristic velocity-pulse graphs recorded in progressively increasing intracranial pressure and their chronology as well. The different forms of the oscillating flow and their successive development are described. The oscillating flow, the systolic spikes and the so called "zero Flow" are the transcranial Doppler signs of the ceased cerebral blood flow, and these signs can be used as one of the evidence of the brain death.

Investigations on oscillating flow spectra as a Doppler ultrasonographic sign of intracranial circulatory arrest

In a total of 90 patients with intracranial hypertension and subsequent intracranial circulatory arrest, the cerebral basal arteries were examined with transcranial Doppler ultrasonography. In order to explain the development of the various forms of oscillating flow, a blood-pressure cuff was placed on the distal forearm of 25 healthy subjects to investigate the flow spectra in the proximal arteries in the presence of increasing stream resistance. With raising the pressure of the cuff, the changes in the Doppler sonographic flow spectra were simulated as in case of increasing intracranial pressure. As intracranial pressure increases at constant systemic blood pressure values, the flow velocity spectrum changes in a typical manner. At the stage of oscillating flow, characteristic changes in the flow spectra can be observed. Investigations showed that compliance is reduced in a distal to proximal direction. This means that a different frequency spectrum can be recorded in distal branches of the middle cerebral artery than in the proximal carotid artery at the same point in time. By examining the flow velocity spectra from the brachial artery, it was possible to understand better the typical course of an intracranial circulatory arrest resulting from increased stream resistance.

Hemodynamic changes after ruthenium irradiation of Hippel's angiomatosis

The authors report a case of Hippel's angiomatosis successfully treated with contact beta irradiation. The area of the multiplex retinal angioma and the accompanying retinal detachment was irradiated with a 106Ru/106Rh radioactive applicator. Hemodynamic changes due to irradiation were followed up in the ipsilateral ophthalmic artery with transcranial Doppler sonography. Scarring was also demonstrated by fluorescein angiography and A- and B-scan ultrasonography. Irradiation caused the narrowing and later the occlusion of the precapillaries and capillaries (i.e. the resistance vessels) and that of the shunts inside the angioma; consequently, vascular resistance increased. Transcranial Doppler sonographic recordings showed a decrease in blood flow velocity as compared to pathologically increased blood flow velocity in angiomas, and a gradual increase in vascular resistance which was lower before treatment.

[Detection of increased intracranial pressure by transcranial Doppler sonography in infants]

The value of transcranial Doppler sonography is demonstrated in two infants with an elevation of intracranial pressure (ICP). One of them suffered from hydrocephalus and ICP increased because of her VP shunt-insufficiency. In the other case status epilepticus caused brain oedema and a rise in intracranial pressure. In both cases, transcranial Doppler sonography showed a decrease in blood flow (CBF) velocity and an increase in the Pourcelot index in the middle cerebral artery. Quick or gradual reduction of the ICP led to an increase in CBF velocity and a decrease in the Pourcelot index. On the basis of experiences of the authors, transcranial Doppler sonography is a valuable method of verifying the elevation of ICP. It is suitable for measuring the effect of treatment necessitated by the elevation of ICP. The method is non-invasive, quick and it can be freely repeated. Therefore it is applicable for monitoring the dynamic of ICP.

[Transcranial Doppler sonography, a new non-invasive method for the study of cerebrovascular circulation]

Transcranial Doppler Sonography. Authors publish the experiences gained by 2300 examinations with Transcranial Doppler Sonography (TDS) which is a new, noninvasive ultrasound method to examine cerebral blood flow velocity in the basal arteries. The theoretical ground and the technique of the investigation is detailed. Mean values of blood flow velocity in the middle cerebral artery of 88 healthy volunteers in different age groups are reported. Authors stress on the numerous advantages of the utilization of this technique. Different pathological alterations of blood flow velocity and characteristic types of velocity-pulse figure are accounted. At last illustrative case reports proving the importance of TDS in different pathological states are presented.

Traumatic brain swelling studied by computerized tomography and densitometry

Two-hundred and fifty-two computerized tomography (CT) scans of 107 patients with head injuries were analyzed. The most frequent consequence of trauma was a diffuse swelling of the brain in 91% of the cases. The severity of brain swelling and its course can be estimated by the compression of (or absence of) the intracranial cerebrospinal fluid space. These observations may be of prognostic value as well. By measurement of the Hounsfield units (HU) in 52 cases the blood or water content in the brain tissues was assessed. An increase in blood content of the tissues (hyperaemia) can account for an increase in Hounsfield values. A decrease in HU suggests brain edema. The density measurements showed that in the first hours and days following head injury, the diffuse brain swelling was caused by severe cerebrovascular congestion in the majority (53%) of the cases. Immediate brain edema without a preceding hyperaemic phase occurs less frequently (32%). Between the 1st and 4th day after injury, edema started to prevail, and between the 5th and 8th day the edematous type of brain swelling was present almost exclusively.

Planum sphenoidale meningioma. Attachment and blood supply

By reviewing clinical and radiological data and surgical findings of 35 so-called "olfactory groove meningioma" cases, the authors conclude that this is not a homogenous group. According to the attachment and blood supply they differentiate two varieties, the planum sphenoidale meningioma (PM) and the olfactory meningioma (OM). It seems possible to distinguish both groups clinically and with regard to the localization of hyperostosis and pneumencephalographic and angiographic findings.