Takayuki Shirakuni

ECTOPIC PITUITARY ADENOMA IN THE SUPRASELLAR CISTERN : CASE REPORT

The case of a 56-year-old man with an ectopic pituitary adenoma is reported. Neurological examinations, neurodiagnostic imaging, surgical observation, endocrinological evaluation, histological examination, and immunohistological study demonstrated evidence of ectopic prolactinoma in the suprasellar cistern and the presence of a normal pituitary in the sella turcica. The patient underwent total removal of the suprasellar mass by a pterional approach, leading to a surgical and endocrinological cure.

Giant cell tumor in cervical spine

A giant cell tumor in the cervical spine of a 67-year-old man complaining of pain in the neck and occipital area is reported. Cervical x-ray films revealed a round destructive lesion in the vertebral body of the fourth cervical vertebra. On the plain cervical computed tomography scan, the most impressive finding was a soap-bubble appearance, which showed a linear high-density area in the mass lesion with destruction of the vertebral body. After embolizing one branch of the artery feeding the tumor, a radical operation was carried out via the anterior approach. The role of cervical computed tomography scanning and computed tomographic myelography in diagnosing and showing the extension of the giant cell tumor is discussed.

Megadolichobasilar anomaly associated with brain stem infarction: A case report

A rare case of megadolichobasilar anomaly associated with localized brain stem infarction showing right hemiparesis and disturbance of consciousness is described. The etiologic mechanisms of brain stem infarction in this anomaly are discussed. The tortuosity and dilatation of the basilar artery were thought to play an important role in the pathogenesis of the brain stem infarction.

Hydrocephalic oedema in normal-pressure hydrocephalus.

The hydrocephalic oedema in normal-pressure hydrocephalus (NPH) was evaluated by measurement of the relaxation time of protons of the water molecules of brain tissue. Patients with NPH were divided into two groups: shunt responders and shunt non-responders. In the group of shunt responders both T1 and T2 of periventricular white matter were significantly prolonged compared to those of controls, and shortened after shunting. Both T1 and T2 of white matter were significantly longer than of gray matter, while a reversed relationship was seen in normal controls. However, in the group of shunt non-responders, T1 of white matter was significantly prolonged, while T2 of the same area not. There was no change in either T1 or T2 of this region after shunting. Both T1 and T2 were almost the same in white and gray matter in shunt non-responders. It is suggested that periventricular abnormalities seen in various diseases may be distinguished on the basis of the relaxation behavior of protons of tissue water.

Cerebral hyperperfusion during surgical resection of high-flow arteriovenous malformations

Cerebral hemodynamics were evaluated in 16 patients with arteriovenous malformations (AVMs) using intraoperative thermogradient or laser Doppler flowmeter. The postexcision/preexcision blood flow ratio was determined. Two of seven patients with large AVMs (> or = 4 cm) developed a postoperative hematoma. Their flow ratios were larger than 1.9. In 4 patients with large AVMs, their blood flow ratios were reduced from an initial ratio exceeding 2.0 to less than 1.5 using carotid or special flow regulation clamps. These patients did not develop any hemorrhagic complication. In 9 patients of small AVMs (< 4 cm), the ratio was significantly low and there were no hemorrhagic complications.

Magnetic Resonance Imaging of Experimental Brain Edema in Cats

The authors observed the natural course of experimental brain edema in vivo using magnetic resonance (MR) imaging. To detect and qualify the edematous lesion, they obtained images by the spin echo technique (repetition time, 2100 ms; echo time, 80 ms). These showed the maximal brain edema on the 1st to 3rd days after the operation, as evidenced by a pixel density study and a finding of mass effect. On MR images enhanced with manganese, the inversion recovery technique (repetition time, 2100 ms; inversion time, 500 ms) demonstrated the edematous lesion as a high signal intensity area with good spatial resolution. Moreover, the follow-up inversion recovery images with manganese suggested that there was a system for absorption of edema fluid between blood vessels and the edematous lesion. The authors think that MR imaging is an important technique for observation of the dynamics of experimental brain edema.

Nuclear magnetic resonance imaging of spinal dissemination of intracranial germ cell tumor: A case report

The authors report a case of multiple spinal dissemination originating from an intracranial germ cell tumor. Nuclear magnetic resonance imaging is a useful and noninvasive study for evaluating multiple dissemination and the effects of therapy, whereas myelography is invasive and demonstrates the lesion as a negative, indirect shadow defect. The usefulness and some problems of nuclear magnetic resonance imaging of spinal tumor are discussed.

Selective Flow Modulation of Proximal Feeding Arteries in Surgery of High-Flow Cerebral Arteriovenous Malformations

Cerebral hemodynamics were evaluated in 7 patients with large high-flow arteriovenous malformations (AVMs) using an intra-operative thermo-gradient flowmeter. The maximum post-excision/ pre-excision blood flow ratio was determined. Special clamps made from silicone tubes with absorbable threads were applied on the proximal feeding arteries.

Injury of Perforating Arteries during Aneurysmal Surgery

Injury of perforating arteries resulting from aneurysmal surgery was studied in 780 aneurysmal cases, and seventeen of these (2.2%) revealed a postoperative hypodensity area on CT due to injury of the anterior choroidal artery, the recurrent artery of Heubner, the lateral lenticulostriate artery and the thalamoperforating artery. Cerebral infarction due to injury of these perforating arteries and the outcome of these patients were evaluated by perand postoperative CT findings, operation records and cerebral angiography. Of the 17 cases showing a postoperative hypodensity area on CT, 9 cases recovered from neurological deficits, but 8 cases retained moderate to severe neurological deficits. Patients with injury of the Heubner artery showed better outcome, but patients with injury of other perforating arteries showed poor outcome. Injury of these perforating arteries was caused mainly by improper frontal lobe retraction, blunt dissection or clipping procedure of broad neck or large aneurysms, or temporary clipping of the parent artery. To reduce injury of these perforating arteries during aneurysmal surgery, it is important to execute careful sharp dissection and to expose the entire aneurymal dome in order to gain precise anatomical understanding as to the perforator, parent artery and aneurysmal neck.

Properties of Interstitial Fluid in the Cerebral White Matter of Patients with Normal Pressure Hydrocephalus

The properties of interstitial fluid in the periventricular white matter in normal pressure hydrocephalus (NPH) were evaluated by measurement of the relaxation times of brain water protons. Patients with NPH were divided into two groups: Shunt responders and shunt non-responders. In the shunt responder group both T1 and T2 values of the periventricular white matter were significantly prolonged compared to those of the controls, and were shortened after shunting. Both T1 and T2 values of the white matter were significantly longer than those of the gray matter, while the reverse relationship was seen in normal controls. However, in the shunt non-responder group, although T1 of the white matter was significantly prolonged, T2 of the same area was not. There was no change in either T1 or T2 of this region after shunting. Both T1 and T2 were almost the same in white and gray matter in shunt non-responders. It is suggested that the periventricular abnormalities seen in various diseases may be distinguished on the basis of the varying relaxation behavior of tissue water.