Comparison of ventricular enlargement and radiopharmaceutical retention: a cisternographic-pneumoencephalographic comparison.

The cisternograms and pneumoencephalograms of 58 patients with suspected "normal pressure" hydrocephalus were correlated and the relationship of ventricular radiopharmaceutical entry and stasis to ventricular size was analyzed. It was found that radiopharmaceutical entry relates directly to ventricular size, stasis occurring only in markedly enlarged ventricles. Cerebrospinal fluid imaging alone is a highly reliable diagnostic study only if patients exhibit the characteristic cisternographic patterns of normal pressure hydrocephalus. In those who do not, pneumoencephalography and cisternography are valuable complementary studies which can also be used to identify primary cortical atrophy.