[Radioisotope cisternographic study on cerebrospinal fluid circulation after subarachnoid hemorrhage]

Although recent advance in neurological surgery has diminished mortality rate of aneurysmal surgery, there still exist several complex problems for the management of aneurysms. Persistent neurological deficits or clinical deterioration after subarachnoid hemorrhage can result from subsequent communicating hydrocephalus which can be treated by shunting operation. We have studied alterations in the cerebrospinal fluid (CSF) circulation after SAH in 43 patients. Sources of hemorrhages were aneurysm in 30 cases, arteriovenous malformation in 6 and unknown in 7. Radioisotope cisternography was performed using 0.5 to 1.0 mCi of 169Yb-DTPA which was given intrathecally by lumbar injection. Results of cisternogram were classified into 4 groups and 7 subgroups; group 0: non filling (4%), group I: persistent ventricular filling (45%), A) absence of convexity flow (11%), B) partial convexity flow (34%), group II: transient ventricular filling (23%), A) delayed convexity flow (11%), B) normal convexity flow (12%), group III: no ventricular filling (28%), A) delayed convexity flow (17%), B) normal convexity flow (11%). The radioactivity in serial blood samples was measured by a well-type scintillation counter. Three types of curves for transfer of 169Yb-DTPA from CSF to blood were classified; delayed type, medium type, and normal type. In delayed type, the count ratio of blood activity at 24 hr to that at 3 hr is over 30%. In normal type, it is below 10%. There was a close correlation between cisternogram and transfer curve. In most cases with persistent ventricular filing, the transfer curve showed a delayed type. The relationship of cisternogram to classification of patient's condition by Hunt was studied. The grade of patient's condition was found to be closely related to the degree of abnormality in CSF circulation. The existence of rebleeding in the patients history was also found to influence the degree of abnormality in CSF circulation. However, single bleeding may also cause abnormality, such as persistent ventricular filling on cisternogram. In regard to the site of aneurysms, those of anterior communicating artery appeared to cause communicating hydrocephalus more frequently. Laterality of convexity flow was analyzed in 17 cases. All cases with internal carotid aneurysms showed decreased activity on the side of bleeding. Shunt operation was performed on 10 cases according to the results of cisternography, transfer curve, pneumoencephalography, and angiography. Seven cases showed improvement and 2 died of other complications soon after the shunt, and the effect of the procedure cannot be evaluated. Patients with clinical signs of NPH and abnormal cisternogram (group I) with evidence of ventricular dilatation are indicated for shunting operation.