R. M. Crowell

In 41 cases of verified ruptured saccular aneurysm, we prospectively predicted the presence or absence of delayed symptomatic cerebral vasospasm. CT criteria quantifying the extent and location of subarachnoid blood (developed in our previous retrospective study) were used in this prospective series of patients. Twenty-two patients had recognizable subarachnoid clots larger than 3 X 5 mm or layers of blood more than 1 mm thick (measured on reproduced images). In 20 of the 22 patients with severe significant clot or thick layer, severe vasospasm was correctly predicted and localized (2 false positives). In 19 patients with no blood, or diffuse blood, or blood outside the subarachnoid space, the absence of severe vasospasm was correctly predicted in 14 (5 false negatives). All of the false-positive and false-negative cases could be explained by inadequate CT technique. The data indicate that the extent and location of blood in the subarachnoid space determine the severity and location of vasospasm and that patients in jeopardy of developing symptomatic cerebral vasospasm can now be identified. Early preventive measures may now be assessed more accurately.

To assess reversibility of focal cerebral ischemia, we performed a neurologic and pathologic study of 27 monkeys subjected to temporary middle cerebral artery occlusion. An implanted snare ligature occluded the artery in awake monkeys for 30 minutes, 4 hours, 8 hours, 16 hours, 24 hours, or permanently. Serial neurologic observations were made for 2 weeks, and systematic neuropathologic examination estimated extent of infarction. Deficits from ischemia were commonly reversible at 30 minutes and 4 hours, but were rarely reversible after 8 hours. Neurologic deficit and infarct size showed remarkable variability. Maximum irreversible infarction evolved in about 4 to 8 hours in most awake monkeys. Variability and reversibility of focal ischemia were probably related to variable collateral circulation. The results suggested that emergency surgical revascularization might help some cases of acute ischemic stroke.

Two patients with cerebral reticulum cell sarcoma (CRCS) are reported in whom neurologic abnormalities and radiologic (computerized tomographic [CT] scan) evidence of tumor remitted. In one patient, remission followed craniectomy and corticosteroid therapy and lasted for eight months. In the other patient, at least four remissions occurred over a span of seven years, each in conjunction with the administration of corticosteroids. Corticosteroids may favorably alter the biologic activity of tumor tissue in some cases of CRCS, predisposing to clinical remission and disappearance of tumor on CT scan.