Tadashi Shibuya

A case of posterior cerebral artery aneurysm associated with idiopathic bilateral internal carotid artery occlusion: case report

BACKGROUND Aneurysms of the posterior circulation are challenging lesions to neurosurgeons, despite improvements in microsurgical techniques and advances in skull base approaches. We present a rare case of a posterior cerebral artery (PCA)-posterior communicating artery (PcomA) junction aneurysm associated with bilateral internal carotid artery (ICA) occlusion successfully treated with an endovascular procedure. CASE DESCRIPTION A 57-year-old female presented with sudden onset of severe headache and loss of consciousness. CT scan showed diffuse subarachnoid hemorrhage and acute hydrocephalus. The patient developed severe neurogenic pulmonary edema and shock. Although her neurogenic pulmonary edema did not resolve, she recovered from shock. However, her general condition was so critical and her vital signs so unstable, that direct surgery under general anesthesia was considered too risky. A cerebral angiogram showed complete occlusion of both internal carotid arteries without any Moyamoya vessels. A saccular aneurysm located at the right PCA-PcomA junction was seen. To obliterate the aneurysm and prevent rerupture, the patient underwent coil embolization via an endovascular approach under sedation with local anesthesia. The balloon remodeling technique was useful to prevent occlusion of parent arteries. Finally, four interlocking detachable coils (IDC) with a total length of 44 cm were used to completely obliterate the aneurysm using the balloon remodeling technique. The patient made a full recovery after treatment and the aneurysm remained obliterated 2 years after coil embolization. CONCLUSIONS We emphasize the advantages of the endovascular approach for the patient in critical condition. We believe that this is the first report of a PCA-Pcom junction aneurysm associated with bilateral ICA occlusion without moyamoya disease.

Gadolinium DTPA-Enhanced Magnetic Resonance Imaging of Cerebral Contusions

The morphological characteristics of cerebral contusions in head trauma patients suggest that an increase in cerebrovascular permeability is responsible for the contusion edema which develops within 1-3 days posttrauma. In the present study, 10 patients with cerebral contusions (mean age, 38 years old; 8 males and 2 females) were examined by gadolinium (Gd)-DTPA enhanced magnetic resonance imaging (MRI) at 1-2 days after trauma. Gd-DTPA (0.3 mmol/kg) was infused intravenously over a period of 30 min. MRIs were taken before, and at 2 and 4 hours after initiation of the Gd-DTPA administration. It was found that contusion edema areas were frequently enhanced by Gd-DTPA at 2 hours. The enhancement diminished at 4 hours. These findings appear to be inconsistent with the results of previously reported similar studies in which enhancement was detected at 6-9 days posttrauma but not during the period earlier than 6 days. This discrepancy may be attributable to the presence of a high blood concentration of Gd-DTPA for a longer period of time and a delay in the time at which MRIs were taken in the present study. The present data indicate that an increased cerebrovascular permeability occurs at as early as 1-2 days posttrauma, and suggest that contusion edema which progresses during the initial 1-3 days may be at least partially vasogenic in nature.

Prevention of Cerebral Thermo-Pooling, Free Radical Reactions, and Protection of A10 Nervous System by Control of Brain Tissue Temperature in Severely Brain Injured Patients

Based on our recent clinical studies, we have presented new concepts for the regulation of brain tissue temperature, a cerebral thermo-pooling brain damage mechanism and prolonged A10 nerve dysfunction in severe head injury patients (6,7,8,9). This understanding of the brain tissue temperature alteration mechanism let to the development of an advanced technique for controlling the brain tissue temperature precisely (6, 7). The results obtained with our cerebral hypothermia treatment and activation of the A10 nervous system indicate that several patients who had been considered difficult to treat by previous methods were saved, and many patients who had clinical signs of brain stem disturbance and vegetative conditions recovered without leaving serious sequelae (4, 7). In this paper, we present new concepts for a secondary brain injury mechanism by elevation of the brain tissue temperature, a protection mechanism through cerebral hypothermia and management of the A10 nervous system in head injury patients.

Importance of Metabolic Monitoring Systems as an Early Prognostic Indicator in Severe Head Injured Patients

We have analyzed and evaluated what is the best metabolic monitoring system to determine the prognosis for maintenance of neurological function in severe head injured patients. Acute subdural hematoma (ASDH) was recognized in fifteen of 22 patients and cerebral contusion in seven in this series. Intracranial pressure (ICP), jugular venous pH and jugular bulb venous oxygen saturation (SjO2) were continuously monitored as soon as possible following stabilization. The measurement of cerebral blood flow (CBF) was carried out using a stable Xenon-computerized tomography (Xe-CT). After measuring CBF, 3% carbon dioxide (CO2) loading was conducted to determine CO2 responses (delta CBF/delta CO2). In patients who died (D), jugular venous pH showed evidence of acidosis (6.3-7.2) with delta CBF/delta CO2 < 1 and cerebral metabolic rate of oxygen (CMRO2) < 1.21 within several hours of the trauma. On the other hand, arterial pH was shown to be within the normal range. In vegetative state (VS) and severe disability (SD) patients, jugular venous pH was shown to be within normal range, with delta CBF/delta CO2 < 1 and 1.44 < CMRO2 < 1.79. In all of moderate disability (MD) and good recovery (GR) patients, jugular venous pH was shown to be within the normal range, with delta CBF/delta CO2 > 1 and 1.65 < CMRO2 < 1.85. These results suggest that jugular venous pH, CO2 response and CMRO2, were useful as early prognostic indicators in the maintenance of neurological function.

Monitoring of Hemodynamic Change in Patients with Carotid Artery Stenosis During the Tilt Test Using Wearable Near-Infrared Spectroscopy

Transient ischemic attack (TIA) is a major complication in patients with carotid artery stenosis. Patients with severe stenosis sometimes complain of orthostatic dizziness, such as syncope. The purpose of this study was to examine the usefulness of near-infrared spectroscopy (NIRS) for evaluating cerebral circulation in patients with carotid artery stenosis during head-up tilt test (HUTT). Fourteen patients with carotid artery stenosis and nine normal control subjects participated. In addition to blood pressure monitoring, hemoglobin (Hb) values (oxy-Hb, deoxy-Hb, and total Hb) were recorded by a wearable NIRS instrument with a high time resolution during HUTT. Oxy-Hb, which decreased initially when the test table was elevated, subsequently increased in normal volunteers and patients with carotid artery stenosis and did not differ significantly between the two groups. However, the oxy-Hb reduction in the carotid artery stenosis group (-0.02 ± 0.03 a.u.) at 30 s after elevation of the table was significantly larger than in the normal group (0.02 ± 0.02 a.u., P < 0.01). Our results indicate that oxy-Hb reduction in patients with carotid artery stenosis may be related to orthostatic dizziness. We concluded that NIRS monitoring is useful for evaluating cerebral autoregulation in patients with severe carotid artery stenosis.

Endovascular Treatment for Ruptured Vertebral Artery Dissecting Aneurysms at the Acute Stage

OBJECTIVE Ruptured vertebral artery dissecting aneurysms (VADA) should be treated promptly because of the high risk of rebleeding. However, it is difficult to treat dissecting aneurysm during the acute stage using microsurgery because of high intracranial pressure or brain edema. Therefore, endovascular treatment of the ruptured VADA may be a better technique. We retrospectively studied the efficacy and outcome of endovascular treatment of ruptured VADA at the acute stage. METHODS Ten patients with ruptured VADA received endovascular treatment at the acute stage. Eight patients who had dissecting aneurysms were treated by internal trapping of the dissected segment. We performed stent-assisted coiling (SAC) for a case of VADA in contralateral hypoplastic VA and a case of bilateral dissections, ruptured VADA of the right VA and VA dissection of the left VA. RESULTS Four patients had good recovery, 3 patients had moderate disability, 2 patients had severe disability, and 1 patient died from initial severe SAH. There was no rebleeding or procedure-related complication. However, one patient who was treated by SAC had ischemic complications post-treatment. CONCLUSION Endovascular treatment of ruptured VADA in the acute stage appears to be safe and effective.

Subependymal CSF Absorption in Hydrocephalic Edema — Ultrastructural Localization of Horseradish Peroxidase and Brain Tissue Damage

The absorption of cerebrospinal fluid (CSF) in hydrocephalic edema was studied in kaolin-induced experimental hydrocephalus in 30 rats by observing the ultrastructural localization of horseradish peroxidase (HRP) as a tracer in relation to neuronal and glial cell brain tissue damage. In the acute stage of hydrocephalus HRP reactive products were diffusely observed in various parts of the deeper brain than in the chronic stage; its reaction products were distributed diffusely in the extracellular spaces and blood vessel walls and some of them were observed in the glial cells and neurons through the routed CSF transport area in both the acute and chronic stage.

Monitoring of Filter Patency During Carotid Artery Stenting Using Near-Infrared Spectroscopy with High Time-Resolution

We aimed to evaluate the usefulness of a newly developed, near-infrared spectroscopy (NIRS) device for monitoring hemodynamic changes during carotid artery stenting (CAS), as a means to detect filter obstruction due to distal embolism. We evaluated 16 patients with internal carotid artery (ICA) stenosis during the CAS procedure, using a NIRS system that can monitor not only changes in oxygenation of hemoglobin (Hb), but also the fluctuation of oxyhemoglobin (oxy-Hb) synchronized with heartbeat. The NIRS system detected a marked decrease of oxy-Hb and an increase of deoxyhemoglobin (deoxy-Hb) during ICA occlusion in patients without anterior cross circulation (ACC). Patients with ACC showed much smaller changes. The analysis of oxy-Hb fluctuation made it possible to detect occurrence of no-flow in the absence of Hb concentration changes. The amplitude of oxy-Hb fluctuation in the no/slow-flow group was significantly smaller than that in the normal-flow group. Our results indicate that the present high time-resolution NIRS device, which can measure oxy-Hb fluctuation, is superior to conventional NIRS for detecting filter obstruction.

Near-Infrared Spectroscopy at the Sagittal Sinus Region: Comparison with Jugular Bulb Oxymetry

Since the first clinical application during the 1940s [1, 2], infrared spectroscopy has become an important clinical technique through the development of a pulsed oxymeter [3]. More recently, near-infrared intracranial spectroscopy (NIS) has been introduced as a technique to monitor oxygenation of the brain noninvasively [4]. The NIS device is usually placed on the scalp of the forehead so that oxygenation of the frontal lobe at the depth of 2.5 cm is monitored [5–8]. Because the total blood volume of the brain consists of 75% venous blood, data from NIS can be regarded as reflecting the balance of oxygen supply and consumption [9, 10]

Densitometry of cerebral circulation in patients with vasospasm during percutaneous transluminal angioplasty

Recently, percutaneous transluminal angioplasty (PTA) has been recognized as a useful therapy for symptomatic vasospasm following subarachnoid haemorrhage. However, some patients have not had a favourable response PTA. In the present study, we attempted to characterise the haemodynamics of such patients by employing densitometric analysis of digital subtraction angiography (DSA). Ten patients underwent PTA because of severe symptomatic vasospasm. The time-density curve (TDC) for each patient was obtained during the PTA procedure by densitometric analysis. Vasospasm was found to be associated with a delayed peak time of the TDC; this was normalized after PTA and neurological improvement was also seen. In contrast, the peak time of TDC remained delayed in three patients who did not show neurological improvement even though the affected vessels were successfully dilated. Delayed TDC that persists after PTA is due to an elevated cerebrovasular resistance in the peripheral microcirculation. The densitometric analysis provides valuable information for choosing suitable therapeutic approaches during PTA.