Detecting extracranial cerebrovascular disease with noninvasive techniques.

Although there are many noninvasive screening tests for extracranial cerebrovascular disease, no single procedure has yet emerged as preeminent. Ophthalmodynamometry is simple but often unreliable. Ocular plethysmography is more complicated and requires moderately expensive equipment. Thermography is often unreliable and also requires costly apparatus. Doppler visualization of the carotid bifurcation is still an experimental tool but looks very promising. Of the currently available techniques, the directional Doppler ophthalmic test has proved most useful in the authors' experience.