Description of the Vasospasm Phenomena following Perimesencephalic Nonaneurysmal Subarachnoid Hemorrhage

Table 2

VS defined by velocity thresholds—distribution by arteries involved.

Variable	Patients
Artery in which VS was detected
Distal BA	24 (77.4%)
MCA	12 (38.7%)
Proximal BA	5 (16.1%)
ACA	4 (12.9%)
PCA	3 (9.6%)
VA	2 (6.4%)
ICA	0
Number of arteries involved per patient
1	19 (61.4%)
2	5 (16.1%)
3	5 (16.1%)
4	1 (3.2%)
5	1 (3.2%)
Total	31  (100%)
Average	1.71

ICA: internal carotid artery; MCA: middle cerebral artery; ACA: anterior cerebral artery; PCA: posterior cerebral artery; VA: vertebral artery; BA: basilar artery; VS: vasospasm.