OBJECTIVES: Symptomatic intracranial atherosclerosis (IA) has an annual stroke risk of 5% - 20%. The study objectives were: 1) to assess economics of existing and emerging IA stenting (IAS) technologies; and 2) estimate the effect of IAS versus anti-platelet therapy (APL) on stroke risk, overall survival (OS), quality-adjusted life years (QALYs), costs, and cost-utility (CU). METHODS: A Markov model was developed to compare IAS with APL from a US perspective in patients with symptomatic IA. The model included the following parameters: 1) procedural complications; 2) restenosis rates; 3) stroke rates of patent or stenosed vessels; 4) mortality after stroke; 5) utilities; and 6) costs of procedure, strokes, and unrelated future resource use. Procedural outcomes of the current model are based on literature findings. Costs in $US 2004 and benefits were discounted at fixed annual rate of 3%. Sensitivity analysis was also performed on the above parameters. RESULTS: With IAS, 74% of patients had patent vessel at six-months; 18% of patients experienced restenosis by 12 months, 11.3% of patients had a procedural complication (3.3% stroke, 6.3% non-stroke, 1.7% death). Stroke risk is predicted to decline from 7.3%/yr from the stenosed, target vessel to 0.5%/yr with patent vessel; and 5%/yr stroke risk in non-target vessels. Over five years, stroke risk is predicted to decline from 44% with APL to 31% for IAS. OS thus is expected to increase by 0.33 years, and 0.24 QALYs. The average cost per IAS procedure is $9,731, with a predicted $8,366 reduction in stroke-related costs and cost-utility of IAS vs APL of $19,963 over a 10-year time horizon. CONCLUSIONS: The cost-effectiveness model shows that IA stenting is predicted to substantially reduce stroke rate, increase overall survival and QALY relative to antiplatelet therapy. The projected CU ratio is considered within acceptable adoption ranges in the US.