The present study examined the benefits of computerized quantitation methods for analysis of digital angiograms to quantify vasospasm. Methods currently used to quantify vasospasm in such experimental settings have several shortcomings. The present method provides quantitative data that none of the others provided. An endothelin-1 (ET-1) induced vasospasm model of the rabbit basilar artery was employed for the study. L-nitro arginine methyl ester (L-NAME) and dexamethasone were applied intra-arterially. Basilar artery diameters were measured by angiography using special software. L-NAME and dexamethasone inhibited the vasospasm caused by ET-1 that was quantified by computerized quantitation methods for analysis of digital angiograms. Computerized quantitation for analysis of digital angiograms is an accurate technique for the measurement of vasospasm. The non-selective nitric oxide synthases (NOS) inhibitor, L-NAME, inhibits the vasoconstriction induced by ET-1 as does the selective immunological NOS (iNOS) inhibitor, dexamethasone, in the proposed doses.