CBF changes during headache-free periods and spontaneous/induced attacks in migraine with and without aura: a TCD and SPECT comparison study.

BACKGROUND: The aim of the present study was to compare cranial arteries blood flow velocity as measured by means of transcranial Doppler sonography (TCD) with mean regional cerebral blood flow (rCBF) as measured by means of single photon emission computed tomography (SPECT) in migraine with and without aura during headache-free periods and spontaneous and/or induced attacks. METHODS: Regional cerebral blood flow (rCBF) and systematic ultrasonic Doppler flow were studied by Technetium-99m hexamethylpropilaminoxime (99mTc-HM-PAO) single photon emission computed tomography (SPECT) and transcranial Doppler sonography (TCD) respectively in controls (n=14) and in migraine with (n=13) and without aura (n=35) during headache free-intervals and spontaneous/histamine-induced attacks. RESULTS: In the migraine without aura group, Doppler flow examinations of the common carotid artery, external and internal carotid artery, ophthalmic artery and middle cerebral artery bilaterally did not reveal significant changes as compared with controls. During attacks, TCD examinations showed a moderate, although not statistically significant, reduction of blood flow velocity in the middle cerebral artery and in the internal carotid artery bilaterally as related to the interictal phase, concomitant with an increase of the flow velocity in the ophthalmic and external carotid artery. SPECT of these patients did not show, on the average, rCBF asymmetries during pain-free periods, although positive findings (i.e., focal hypoperfusion) were found in approximately half of the cases. During attacks, 74% of patients displayed a unilateral hypoperfusion, mainly in the occipital region. Low-flow areas were generally but not always consistent with the site of pain. In the migraine with aura group, significant reduction of blood flow velocity in middle cerebral artery was recorded by TCD on the affected side during attacks, as compared with the pain-free side. Hypoperfusion was registered between attacks by SPECT in approximately 2/3 of the patients. During attacks, a marked reduction of rCBF occurred in most patients (85%), mainly in the parieto-occipital region. The posterior rCBF asymmetries revealed at the SPECT and consistent with the general reduction of blood flow velocity documented by TCD may be related to cerebrovascular tone instability. CONCLUSIONS: Our findings do not support the paradigm that migraine with and without aura are two different entities.

[Transcranial Doppler for the monitoring of gas embolism in neurosurgical operations in the sitting position]. / Doppler transcranico per il monitoraggio dell'embolia gassosa negli interventi neurochirurgici in posizione seduta.

The risk of venous air embolism is significant in neurosurgical procedures performed in the sitting position. Monitoring for venous air embolism, therefore, is crucial and can be approached from several aspects. The most sensitive generally applicable clinical method for the detection of intracardiac gas is based on an application of the Doppler principle. The Authors describe the technique used to adapt a transcranial Doppler (TC 2-64 B, EME, Germany), and a probe designed to record the Doppler signal from intracranial arteries (Transcran FP 2, EME, Germany), as precordial Doppler in order to monitor venous air embolism in neurosurgical procedures performed in the sitting position.

[Complications during preoperative embolization in intracranial meningioma]. / Complicanza in corso di embolizzazione pre-operatoria di meningioma intracranico.

We report a rare case of meningioma of the parieto-occipital convexity accompanied by hemorrhage in the tumor and in the subdural space that occurred while pre-operative embolization was being applied. The patient, a 48 year old woman, presented sudden headache and, in a few minutes, comatose status and decerebrate rigidity. A quick diagnosis with CT-scan of acute intratumoral and subdural hemorrhage and a rapid intervention on the patient led to complete recovery. The possible reason for the hemorrhage is the sudden change in blood pressure of pathologic small vessels triggered by embolization.

Cerebral blood flow velocity and cerebrospinal fluid pressure after single bolus of propofol.

The effects of propofol on cerebral blood flow velocity, cerebrospinal fluid pressure, cerebral perfusion pressure and mean arterial pressure were studied during induction in 25 patients scheduled for elective craniotomy. Premedication consisted of only atropine sulphate 0.007 mg/kg (im) 45 min before induction. Measurements were made or derived at time zero and 1, 2, 3, 4 and 5 min after an induction dose of propofol (2.5 mg/kg). Patients were retrospectively stratified into two groups, according to cerebrospinal pressure basal values: (i) lower than 10 mmHg (10 pts) and (ii) higher than 10 mmHg (15 pts). Cerebral blood flow velocity, measured by transcranial Doppler, fell in all the patients, but the reduction was significant at 1, 2, 3 and 4 min only in the group with high CSF pressure, while it never reached the critical value of 10 cm/s. Cerebrospinal fluid pressure and mean arterial pressure decreased in both groups of patients and the fall reached a statistical significance at 1 and 2 min in the group with higher baseline CSF pressure, only at 1 min: a parallel decrease of CPP was recorded, but it was not significant. Thus propofol decreases CSF pressure without hazardous effects on cerebral blood velocity and on cerebral perfusion pressure and seems to be a suitable anaesthetic agent in controlling high cerebrospinal fluid pressure in neuroanaesthesia.

Percutaneous selective thermorhizotomy in the treatment of "essential" trigeminal neuralgia. The importance of lesion selectivity.

Results following percutaneous thermorhizotomy for trigeminal neuralgia are described in 111 patients. Recurrences and side effects are more frequent whenever selectivity of the surgical lesion has been imperfect (exceeding the original pain area and causing marked hypoesthesia), and less frequent in the cases with strictly selective lesion.