“…The vascular anomaly produced by the FCA mutation has received little attention in the past because individual lesions were difficult to detect on routine angiograms, pneumoencephalograms or skull radiographs. To be detected by radionuclide scanning the lesion must have a diameter of at least 20 mm [Kawi, 19781; with routine angiography only a subtle blush or unusual venous drainage pattern may be apparent [Kramer, 1977;Voigt, 1976;Kawi, 1978;Numaguchi, 1977;Bartlett, 1977;Jonutis, 1971;Segall, 19741 although selective, high dose, prolonged angiography may be useful [Numaguchi, 19791. CCT scanning has dramatically improved the detection rate [Kramer, 1977;Bartlett, 19791 and confirmed the pathologists' suspicion that these lesions are not rare occurrences [Russell, 19711. Moreover, as demonstrated here, CCT can be particularly useful in detecting bleeding lesions in functionally silent areas (eg, frontal lobe) and small nonhemorrhagic lesions not clinically apparent, though located in critical areas of the brain. The relatively high incidence of clinical symptoms and the ease of surgical removal underscore the importance of correctly diagnosing the lesion.…”