Haruhide Ito

Immunohistochemical localization of tissue-type plasminogen activator in the lining wall of chronic subdural hematoma.

Capsules of chronic subdural hematoma were immunohistochemically stained with monoclonal antibody against tissue-type plasminogen activator. Endothelial cells of sinusoids and capillaries in the outer membrane showed strong immunostaining. Endothelial cells of veins and arteries in the dura mater showed moderate and weak staining. No cells other than the endothelial cells were stained. In the inner membrane, tissue-type plasminogen activator immunoreactivity was not seen. The mean concentration of tissue-type plasminogen activator in the hematoma content was higher than that in the plasma. The more the sinusoids in the outer membrane were developed, the higher the concentration of tissue-type plasminogen activator contained in the hematoma fluid. In chronic subdural hematoma, overproduction and oversecretion of tissue-type plasminogen activator from the sinusoidal and capillary endothelial cells in the outer membrane cause increased fibrinolysis, which in turn impairs hemostasis, and hemorrhage from the capillaries recurs, resulting in enlargement of the chronic subdural hematoma.

Tissue-type plasminogen activator in the chronic subdural hematoma

We measured the concentrations of tissue-type plasminogen activator (t-PA) in 92 patients with chronic subdural hematoma involving 102 sites. The t-PA level in the normal plasma was 4.0 +/- 1.8 ng/mL (mean +/- SD), while that in the hematoma content of these patients was 11.2 +/- 6.2 ng/mL. Patients showing stupor (grade 3) and coma (grade 4) had higher t-PA levels than those showing headache (grade 1) and somnolence (grade 2) or psychiatric disorder (grade 5). Also, those with the layer-type hematoma on computed tomographic images had higher t-PA levels than those with any other types. The t-PA level in the draining fluid decreased after surgery. In three patients showing a gradual increase of t-PA, subdural fluid reaccumulated and the general condition remained unchanged after surgery. Overproduction of t-PA is considered to initiate intermittent hemorrhage by conversion of plasminogen to plasmin and results in persistence or enlargement of chronic subdural hematoma.

Symptomatic duplication of the vertebral artery

A case is presented of extracranial duplication of the vertebral artery in a patient who had spinal cord symptoms for 26 years. Vertebral angiograms and computed tomography with metrizamide enhancement demonstrated a bypass artery of the duplication compresing the upper cervical spinal cord intradurally at the level of the atlas; this finding was verified at operation. The symptomatology and clinical significance of this rare case are discussed.

Single extracranial-intracranial duplication of the vertebral artery

Duplication or fenestration of the vertebral artery is an unusual vascular variation previously described as present either at the extracranial segment (atlantoaxial level) or at the intracranial segment of the artery. This report describes such a duplication that extended from the extracranial to the intracranial segment and was revealed by angiography. The embryologic genesis and potential clinical significance of this condition are discussed.

Relation of regional cerebral blood flow to hemiparesis in chronic subdural hematoma

To investigate the causative mechanism of hemiparesis in chronic subdural hematoma, 38 patients with unilateral chronic subdural hematoma were studied on the relationship between their clinical manifestations and regional cerebral blood flow measured with 133xenon inhalation (16 detectors on each side of the head, Initial Slope Index). Twenty-five patients with hemiparesis (hemiparesis group) and 13 patients with headaches only and without any neurological deficits (headache group) were examined before surgery for chronic subdural hematoma. Among the hemiparesis patients, 15 were examined after surgery. Preoperative regional cerebral blood flow values in the headache group were normal in all regions bilaterally and showed no significant regional difference in one hemisphere or interhemispheric difference between the corresponding regions in both hemispheres, whereas preoperative regional cerebral blood flow values in the hemiparesis group were generally around the lower limit of the age-matched normal value and were subnormal in some areas, and the regional cerebral blood flow values were significantly lower on the hematoma side than on the intact side in most regions. The rolandic region especially showed the lowest regional cerebral blood flow value of 32.3 in the Initial Slope Index on average and the most significant interhemispheric differences of regional cerebral blood flow. Such a preoperative reduction of regional cerebral blood flow in the hemiparesis group normalized along with clinical improvement after evacuation of the hematoma. It was suggested that localized cerebral blood flow reduction at the rolandic cortical region under the hematoma might be one of the causative factors of hemiparesis in chronic subdural hematoma.

Preoperative diagnosis of Rathke's cleft cyst

Two cases of Rathkes cleft cyst are presented. The cysts showed as high-density lesions on plain CT with slight enhancement with contrast medium. They appeared as a hyperintense mass in the T1-weighted magnetic resonance images. Preoperative diagnosis is very important because different sellar cystic lesions require different treatment.

Effective preoperative irradiation of highly vascular cerebellopontine angle neurinomas

Three cases of large cerebellopontine angle neurinoma with marked vascularity and tumor staining on the angiogram were treated with effective preoperative irradiation. The radiotherapy was given before the second operation in two cases and before the first operation in the other case. Irradiation doses administered with a linear accelerator were 2.34 to 3.0 Gy for 3 to 3.5 weeks, and radical operations were done 1.5 to 2 months after irradiation. After the irradiation, vertebral angiography showed moderate to marked decrease of the hypervascular capsular stain and disappearance of the early draining vein. Computed tomographic scan showed enlargement of the central necrotic area within the heterogeneously enhanced tumor, which was unchanged in size. Radical operations, which had been impossible because of uncontrollable massive bleeding, were successful without any intraoperative bleeding after radiotherapy. Postirradiation radiological findings corresponded well with those of histopathological examination, which showed decrease in cellularity and in vascularity and diffuse coagulation necrosis around the collapsed tumoral vessels as radiation effects. Preoperative irradiation of the hypervascular neurinoma was though to facilitate radical surgery by abolishing or diminishing the risk of intraoperative bleeding.

Relationship Between Cerebrospinal Fluid Flow Through the Ventriculo-peritoneal Shunt and Computed Tomographic Images of Hydrocephalic Patients

Quantitative measurements of cerebrospinal fluid flow through the ventriculo-peritoneal shunt using radioisotope were carried out on 34 hydrocephalic patients (18 children and 16 adults) and the relationship between the flow rates and the computed tomographic (CT) scan images was studied. 1) The flow rates in the prone position was 0.04–0.20 (mean+S.D., 0.10+0.05) ml/min in 13 patients whose shunt systems were functioning adequately. There was a good correlation between the flow rates and closing pressures of the shunt valves. 2) The 21 patients with malfunctioning shunt systems were devided into two groups as follows; the obstruction or lower flow group in which shunt flow was in 0–0.05 ml/min and the overflow group with rate over 0.20 ml/min. In the former group, there were 3 cases in which the shunt flow in a sitting position was very low and the cause of the malfunction was thought to be placement of an inadequate system with a higher pressure valve. 3) In 4 cases of 5 children in which the ventricles were of normal size during shunt malfunction, their ventricular sizes on CT images changed to small or slit-like ventricles after shunt revision. 4) A few cases of hydrocephalic adults, in which the shunt-catheters were thought to be obstructed with no shunt flow in the prone and sitting positions showing no progressive dilatations of the ventricles on CT images, were diagnosed with the added findings of RI cisternography as shunt-independent arrested hydrocephalus. In the diagnosis of shunt malfunction and selection of the most adequate system in shunt revision, it is necessary to analyze together the data on CT images, quantitative measurement of shunt flow rates and RI cisternography as well as the clinical manifestations.