Intracranial bruit: Charles Warlow's challenge revisited.

Over 20 years ago, Charles Warlow, the founding editor of Practical Neurology, offered a copy of his stroke textbook to anyone diagnosing an intracranial arteriovenous malformation by auscultation of the skull alone. This article examines the possible diagnostic value of intracranial bruit in terms of the 2×2 contingency table for diagnostic tests and recounts an historical case.