Yujiro Shiroyama

The effect of EC-IC bypass surgery on resting cerebral blood flow and cerebrovascular reserve capacity studied with stable Xe-CT and acetazolamide test

SummaryCerebral blood flow (CBF) and cerebrovascular reserve capacity (CRC) were measured by stable xenon computerized tomography (Xe-CT) and acetazolamide test in 15 patients with cerebrovascular disease before and after extracranial-intracranial (EC-IC) bypass surgery for minor stroke, reversible ischemic neurological deficit or transient ischemic attack. All had angiographically shown occlusive lesions of the major arterial trunk. In the present series, global analysis showed that the bypass did not increase the resting rCBF, but did increase the rCRC. We divided the patients into four groups according to the preoperative resting rCBF and rCRC. All 3 patients with normal resting rCBF and reduced rCRC showed postoperative improvement of rCRC. Of 6 patients with reduced CBF and reduced CRC, three had postoperative increase in resting CBF and four had increased CRC. One of two patients with reduced CBF and normal CRC showed only an increase in CRC. We propose that reduced CRC or reduced CBF with reduced CRC are criteria for selection of candidates for bypass surgery. We conclude that Xe-CT with the Diamox test is a useful and simple method for evaluating cerebral hemodynamics. Preoperative grouping with a combination of preoperative resting cCBF and preoperative rCRC is useful for predicting the effect of EC-IC bypass surgery.

Balloon occlusion of a spontaneous carotid-cavernous fistula in ehlers-danlos syndrome type IV

A case of spontaneous carotid-cavernous fistula associated with Ehlers-Danlos syndrome Type IV was treated successfully by transarterial balloon embolization. To minimize the stress to the arterial wall, we detached three silastic balloons with low-attachment force in the cavernous sinus with the aid of a proximal balloon to control the high flow of the fistula. To achieve complete obliteration, we had to inflate the third balloon to dimensions that occluded the cavernous portion of the internal carotid artery. Patients with Ehlers-Danlos syndrome Type IV carry a high risk when undergoing any diagnostic or therapeutic endovascular procedure due to the fragility of their blood vessels. Recognition of this entity is important and special attention should be paid to its pathophysiology for a successful treatment.

The relationship of cloverleaf skull syndrome to hydrocephalus

In 1960, Holtermüller and Wiedemann described chondrodystrophic hydrocephalus as Kleeblattschädel syndrome. In the present paper, we review 23 cases of this syndrome associated with hydrocephalus, including 2 cases of our own. Of these 23 cases, 8 involved communicating hydrocephalus and 15 non-communicating hydrocephalus. It has been speculated that the associated hydrocephalus results from basilar impression, compression of infratentorial structures, aqueductal stenosis in non-communicating hydrocephalus, and impairment of venous drainage and cerebral spinal fluid flow at the level of the constrictive cranial ring in communicating hydrocephalus. Our present cases also showed this cranial ring, as demonstrated by skull X-rays and computed tomography scans. Since cloverleaf skull syndrome often has other general anomalies, we consider the hydrocephalus in this syndrome to have causes associated wtih the osteocartilaginous system.

Comparison of Xe‐CT/CBF and quantitative ECD‐SPELT

We compared stable xenon enhanced X‐ray computed tomography (Xe‐CT) with Technetium‐99m ethylsteinate dimer single‐photon emission computed tomography (ECD‐SPECT) in 12 patients. We evaluated the cerebral blood flow (CBF) values in the territory of the anterior, middle and posterior cerebral artery, and in the thalamus. The CBF values were higher in ECD‐SPECT than in Xe‐CT except for the values of the thalamus. The posterior cerebral artery territory showed a lower correlation and the thalamus had no correlation between two methods. We discussed causes of these differences.

Apnea associated with Chiari malformation: medullary hemorrhage revealed by MRI

Medullary hemorrhage in the medulla oblongata of an infant with Chiari malformation, hydrocephalus, meningomyelocele and hypogenesis of the corpus callosum is reported. Four days after placement of a ventriculoperitoneal shunt, spontaneous respiration diminished. Magnetic resonance imaging (MRI) successfully revealed a small medullary hemorrhage.