Satoshi Kuwabara

Hyperaemia prior to acute cerebral swelling in severe head injuries: The role of transcranial doppler monitoring

SummaryAcute cerebrovascular congestion after a closed head injury is significantly related to intracranial hypertension. As an indirect method of cerebral blood flow measurement, transcranial doppler sonography (TCD) provides a rapid and noninvasive assessment of cerebral haemodynamics, including hyperaemic conditions.TCD examinations was serially performed in 35 patients with severe head injury with intact cerebral circulation; i.e. the mean flow velocity (MFV) patterns of the middle cerebral artery (MCA) did not show signs of cerebral circulatory arrest such as systolic spike, to and fro, or no flow. The results showed that the MFV of the MCAs and ipsilateral extracranial internal carotid arteries (ICAs) in 9 of these patients increased sharply and pulsatility index (PI) decreased during 48–96 hours after the injury. This was soon followed by patterns of high intracranial resistance, consistent with elevated intracranial pressure (ICP) in monitored patients and acute brain swelling on repeated computed tomographic (CT) scans. The correlation between increased MFVs, decreased PIs, and cerebral haemodynamic changes leading to acute brain swelling is discussed.The number of patients who ended with severe disability, vegetative state, or death was 66% in this group of 9 patients, compared to only 34% for the 35 patients overall with severe head injury. Though the morbidity and mortality rates largely depend on the primary injury, the presence of acute cerebral swelling aggravate the grave course in these patients. And the ability of TCD to monitor the hyperaemic state prior to oedema should lead us to adjust the therapy in order to minimize the secondary insult related to intracranial hypertension.

Cerebral circulation in moyamoya disease: A clinical study using transcranial doppler sonography

Transcranial Doppler sonography was performed on eight patients diagnosed as Moyamoya disease. Angiographically, the patients-four adults (mean age 42) and four children (mean age 7.7)-underwent a complete six- or five-vessel angiographic study. The results showed the following: (1) Despite the presence of stenosis, all middle cerebral arteries showed very low-flow velocity compared to their ipsilateral distal internal carotid arteries. In adult cases, the difference was very significant (p < 0.02). (2) Relatively high-flow velocity was observed in the posterior cerebral arteries of children, and in the ophthalmic arteries of adult cases. (3) In several occasions, very low-flow velocity values were still detected despite the fact that with angiography, the respective arterial segments were hardly opacified. The relation and discrepancy between these results and the angiographic findings, and the potential application of transcranial doppler in assessing and grading the severity of moyamoya disease are discussed.

Transcranial doppler sonography in carotid-cavernous fistulas: Analysis of five cases

Transcranial doppler sonography was performed transorbitally in five patients clinically diagnosed as unilateral carotid-cavernous fistula. Dural arteriovenous malformation related-shunts were detected in all the patients. In the normal eyes, the only doppler signals observed at an insonation depth of 45 to 55 mm were those of the ophthalmic artery. In the affected eyes, abnormal doppler signals with relatively higher flow velocity and lower resistance were observed. In three of the cases, these abnormal signals showed a flow directed anteriorly or away from the cavernous sinus, consistent with changes in the ophthalmic veins caused by the presence of the shunts. In two cases, however, the observed flows were directed posteriorly, the normal direction of these veins. The possible explanations for this discrepancy are discussed in relation with angiographic findings. The use of transcranial doppler might provide a better understanding about hemodynamic changes in carotid cavernous fistulas.

A new model of brainstem ischemia by embolization technique in cats

An experimental model of brainstem ischemia was developed by embolization technique with cylindrical silicone rubber emboli in cats. The embolus reached the basilar artery in 55 cats (58.5%) and stopped in the upper basilar artery (UB) in 32, the middle basilar artery (MB) in 22 and the lower basilar artery (LB) in one animal. When the basilar artery distal to the embolus was not visualized (type 1) by postoperative vertebral angiogram. Evans blue extravasation was observed in the brainstem caudal to the embolus. When only a filling defect of the basilar artery at the site of the embolus was noted (type 2), dye extravazation was observed in the brainstem around the site of the embolus. In UB type 1, the regional cerebral blood flow of pons and medulla oblongata decreased immediately after embolization, and six hours after embolization it was 11.4±5.7 (pons) and 11.7±4.6 ml/100 g/min (medulla oblongata). In UB type 1 and MB type 1 animals, coma, apnea, tetraplegia, and disturbance of swallowing were noted. These animals died within 50 hours after embolization. Animals of UB type 2 and MB type 2 showed neurological deficits, but survived for three days. This paper discusses this method of producing experimental brainstem ischemia, the sites of ischemic lesions, and clinicopathological findings.

Prenatal diagnosis of open spina bifida by MRI and ultrasonography

A case that was diagnosed prenatally as having open spina bifida by magnetic resonance imaging (MRI) and ultrasound (US) examination is reported. At the time of the third US examination, the spina bifida cystica was detected, but it could not be determined by US whether it was open or closed spina bifida. A lumbosacral skin defect was detected on MRI, which permitted prenatal diagnosis of open spina bifida. Surgical repair was performed immediately after delivery. Prenatal intrauterine evaluation of the fetal CNS morphology and malformation has advanced with the improvement of diagnostic tools. Each diagnostic tool, however, has its own advantages and disadvantages. In prenatal intrauterine evaluation, it is important that observation be made through the combined use of multiple diagnostic tools.

Arteriovenous malformation at the cervicomedullary junction: A case report with magnetic resonance imaging

A rare case of arteriovenous malformation at the cervicomedullary junction is reported. A 72-year-old man developed symptoms of total transection of the upper cervical cord without evidence of subarachnoid hemorrhage. The arteriovenous malformation had an intramedullary nidus with an aneurysmal dilatation at the C-1 level. This lesion was diagnosed by magnetic resonance imaging and confirmed at autopsy. The neurological symptoms may have been due to compression of the spinal cord by the intramedullary lesion, followed by degeneration and necrosis. The usefulness of magnetic resonance imaging in the neuroradiological diagnosis is particularly emphasized.

Vasospasm after traumatic subarachnoid haemorrhage: Transcranial Doppler evaluation. Case report

A case of vasospasm after traumatic subarachnoid haemorrhage (SAH) is reported here. Transcranial Doppler Sonography (TCD) was used to evaluate mean flow velocity (MFV) changes of the basal cerebral arteries related to vasospasm. Accelleration of MFV of the right middle cerebral artery (MCA) indicating vasospasm was first noted on TCD evaluation, and then proved by carotid angiography (CAG). Evaluation of all TCD results revealed that the process of relaxation or normalization of the spastic artery started from the proximal side of the basal intracranial artery and gradually moving to the distal side. This interesting phenomenon could be a common process found in vasospasm cases.

Angiographic extravasation of contrast medium in a case of ruptured arteriovenous malformation.

SummaryA case with angiographic extravasation of contrast medium from ruptured vessels in an arteriovenous malformation is reported and a review of the literature presented.

Cerebral Hemodynamics in Arteriovenous Malformations

Cerebral hemodynamics were studied in 3 patients with supratentorial arteriovenous malformations (AVMs). Cerebral blood flow (CBF) was measured by the methods using 123 I-IMP SPECT (IMP SPECT) and stable xenon CT (Xe-CT) before and after surgery. In addition, the cortical blood flow (CoBF) adjacent to AVMs was monitored during surgery using laser Doppler flowmetry. Preoperative CBF measurements were performed more than a month after stroke. Case 1: A 48-year-old man developed disturbance of consciousness, right hemiparesis and motor dysphasia. Cerebral angiography disclosed a 3.5 cm left frontal AVM fed by middle cerebral artery. In preoperative IMP SPECT and Xe-CT, hypoperfusion and low CBF were observed in the left frontoparietal region adjacent to the AVM. The CoBFs of the left frontal lobe were increased moderately during clipping of feeders and after excision of the AVM. Case 2: A 51-year-old woman had vomiting and right hemiparesis. Angiography demonstrated a 2.0 cm left parietal AVM. In preoperative CBF studies, neither hypoperfusion nor low CBF was seen in the areas surrounding the AVM. There were no alterations of CoBFs before and after excision. Case 3: A 62-year-old man had a 5.0 cm left frontoparietal AVM supplied by anterior and middle cerebral arteries. Preoperative CBF studies showed marked hypoperfusion and ischemia in the regions adjacent to as well as distant from the AVM. A large increase in CoBF up to two or three times the preexcision value was noted after total excision of the AVM. He developed the normal perfusion pressure breakthrough (NPPB) syndrome after operation. High dose barbiturate anesthesia combined with induced hypotension was maintained for 5 days and resulted in good outcome. From reported clinical observations and hemodynamic data in this study, it is suggested that factors contributing to the development of NPPB syndrome include: (1) a large, high-flow AVM; (2)

Cerebral Hyperemia Prior to Acute Cerebral Swelling in Patients with Severe Brain Injuries: The Role of Transcranial Doppler Monitoring

Acute cerebrovascular congestion after a closed head injury is significantly related to intracranial hypertension. As an indirect method of cerebral blood flow measurement, transcranial doppler sonography (TCD) provides a rapid and noninvasive assessment of cerebral hemodynamic, including hyperemic condition.