Power Doppler imaging: Initial evaluation as a screening examination for carotid artery stenosis

PURPOSE: To evaluate power Doppler imaging as a possible screening examinat ion for carotid artery stenosis. MATERIALS AND METHODS: In the principal pilot study, a prospective, blinded comparison of power Doppler imaging with duplex Doppler imaging, the refer ence-standard method, was conducted in 100 consecutive patients routinely r eferred for carotid artery imaging at a large, private multispecialty clini c. In the validation pilot study, a prospective, blinded comparison of powe r Doppler imaging with digital subtraction angiography, the reference-stand ard method, was conducted in 20 consecutive patients routinely referred at a teaching hospital. Using conservative assumptions, the authors performed cost-effectiveness analysis. RESULTS: Power Doppler imaging produced diagnostic-quality images in 89% of patients. When the images of the patients with nondiagnostic examinations were regarded as positive, power Doppler imaging had an area under the rece iver operating characteristic curve, A, of 0.87, sensitivity of 70%, and sp ecificity of 91 %. The validation study results were very similar. The cost -effectiveness of screening and, as indicated, duplex Doppler imaging as th e definitive diagnostic examination and endarterectomy was $47,000 per qual ity-adjusted life-year. CONCLUSION: The A, value for power Doppler imaging compares well with that for mammography, a generally accepted screening examination, and with most other imaging examinations. Power Doppler imaging is likely to be a reasona bly accurate and cost-effective screening examination for carotid artery st enosis in asymptomatic populations.