The posterior inferior cerebellar artery arising from the extracranial segment of the internal carotid artery via the hypoglossal canal without an interposed segment of the basilar artery: a persistent primitive hypoglossal artery variant.

The authors present a rare case of a persistent primitive hypoglossal artery (PHA) variant ending in the posterior inferior cerebellar artery (PICA) without an interposed segment of the basilar artery and describe briefly the possible embryogenesis of this anomaly.

[Computed tomography of brain infarct with special reference to vascular territories and collateral pathways].

The essential approach to CT diagnosis is to evaluate precise radiological findings. However, in some cases, other additional information may play an important role in the detection of disease itself. In brain infarct, this can include clinical symptoms, the hemodynamics of cerebral circulation, and other factors. From this point of view, the normal vascular territories of the brain and collateral pathways in cerebral stenotic or occlusive vascular diseases are described, and representative cases are presented.

[A case of cervical liquorrhea with headache in and around the area of the great occipital nerve].

We report a 44-year-old man who had sudden-onset severe pain with ardor at the left occipital and nuchal region without trauma in July, 1992. Severe pain disappeared soon after, but dull pain continued intermittently. Four months later, he was referred to our hospital. Neurological examination showed no abnormalities. Cervical CT scan and myelography disclosed liquorrhea. Digital subtraction myelography confirmed cerebrospinal fluid leakage from the level of C1/2 disc. He underwent laminectomy of C1 and C2, and dural plasty on April 6, 1993 with subsequent disappearance of headache. We suppose that this headache was due to rupture of the root sleeve and compression to the root and dorsal root ganglia by outflowed liquor.

Dose distribution and shrinkage of acoustic neurinomas 2 years after Gamma Knife treatment.

To examine the relationship between dose distribution and tumor shrinkage of acoustic neurinomas, correlation coefficients between distribution probabilities of some dose areas and residual tumor ratios of 21 cases were studied at 2 years. Approximating a dose-volume histogram to beta-distribution, two essential dose areas for tumor control were extracted: a dose area from 14.2 to 24.7 Gy contributed to tumor shrinkage, whereas a dose area from 27.3 to 29.4 Gy was contraindicated. Given that there are at least two different dose areas with reverse characters, a formula with two opposing logistic components is proposed to predict tumor control. With this formula, Gamma Knife treatment of acoustic neurinomas may be optimized.

Fast spin-echo MR imaging of non-Hodgkin lymphoma arising from chronic tuberculous empyema.

Non-Hodgkin lymphoma (NHL) rarely arises from tuberculous empyema. We report a case in which magnetic resonance (MR) imaging was useful in separating the lymphoma from the chronic empyema.

[A case of carpal tunnel syndrome caused by a ganglion cyst--diagnosis and follow-up study with magnetic resonance imaging].

We report a case of carpal tunnel syndrome (CTS) caused by a ganglion cyst which was diagnosed by magnetic resonance (MR) imaging of the left wrist. MR images depicted a 10-mm ganglion cyst which pressed the median nerve toward the ulnar side. The ganglion cyst was punctured under direct endoscopic visualization in the carpal canal, subsequently the clinical and the electrophysiologic findings of CTS improved. The median nerve was delineated in its proper position. MR imaging of the wrist, a noninvasive means to observe median nerve, is useful for the diagnosis and the follow-up study of CTS.

Vertebrobasilar insufficiency: correlation of clinical and radiologic findings.

Radiological and clinical findings of 20 cases with angiographically proven stenosis or occlusion of the vertebrobasilar system and with clinical signs and symptoms attributable to posterior circulation disorder were studied. A simplified classification of vertebrobasilar arterial disease was presented; type I refers to stenosis of the vertebrobasilar system or subclavian artery, type II refers to vertebrobasilar occlusion, and type III refers to vertebrobasilar branch disease. Type I lesions were further subdivided into types Ia and Ib; type Ia cases showed no infarction in the posterior territory, whereas type Ib cases showed one or more infarctions on computed tomography or magnetic resonance imaging. This angiographic classification is based on treatment options that can be adopted to specific types of lesion. In type I cases, lesions are usually amenable to surgical or angiographic intervention. In type II cases, short-term anticoagulation is the treatment of choice. In type III cases, treatment is primarily aimed at prevention of complication and further stroke.

Extravasation of contrast medium into the subdural space during cavernous sinus venography: a rare complication.

We recently observed subdural extravasation of contrast medium during transfemoral catheter venography of the cavernous sinus, performed to elucidate the relationship between a parasellar mass and the sinus. The precise mechanism is unknown but a dural tear during manipulation of the guide wire or catheter was thought to be the most likely cause.

[CT evaluation of blow-out fractures].

Fifty patients with blow-out fracture were analysed in detail by using CT. Among these cases, 38 and 12 cases were classified as pure type and impure type fractures, respectively. The lesion of pure type noted in five positions of the orbit; floor, roof, medial wall, corner, and floor with medial. The shape of fracture fragments were observed as trap door, punched out, broad and linear in floor type fracture. Herniated ophthalmic muscles were detected in approximately half of the pure type fractures. CT scan plays an important role in the decision to operate on blow-out fracture.

Utilization of therapeutic embolization in haemorrhage caused by carcinoma of the tongue.

Selective transcatheter arterial embolization, using Gelfoam, was performed in 2 patients with bleeding from tongue arteries due to carcinoma. Though the patients were in poor general condition, being in the terminal stage of cancer, there were no complications and the bleeding was successfully controlled. This method was effective in controlling haemorrhage from the tongue due to carcinoma of the tongue.

[Multiple cerebral venous angiomas associated with mixed pial and dural arteriovenous malformation].

Venous angioma is a relatively rare entity of vascular malformations of the brain and usually found as a solitary lesion. Cases of multiple lesions and/or coupled with other vascular malformations are extremely rare. We present the first case of multiple supratentorial venous angiomas associated with mixed pial and dural arteriovenous malformation (AVM) fed by the posterior cerebral artery, the occipital artery and the posterior meningeal artery.

CT demonstration of portal vein aneurysm.

We report a case of portal vein aneurysm showing characteristic enhancement on dynamic CT.

Computed tomography of intracranial chondroma with emphasis on delayed contrast enhancement.

Intracranial chondroma is an unusual cartilaginous tumor originating from the base of the skull. We report on two cases of intracranial chondroma that showed delayed contrast enhancement on CT after high-dose administration of contrast medium. This CT feature may be useful to differentiate chondromas from other tumors of the skull base such as meningiomas and neurinomas.

Anomalous origin of the posterior meningeal artery from the lateral medullary segment of the posterior inferior cerebellar artery.

The authors present two cases of angiographically-confirmed anomalous origin of the posterior meningeal artery (PMA) from the lateral segment of the posterior inferior cerebellar artery (PICA) and describe briefly the probable embryogenesis of this anomaly.