[Pneumographic signs of poorly compensated hydrocephalus]

A definition of "Hydrocephalus not completely arrested" is not easy to be given. Cerebral pneumography represents the most detailed neuroradiological examination. In spite of this, neither its analysis nor its measurements bring definite criteria for the favorable moment of locating a shunting system in that case. These criteria are reviewed systemetically. It is pointed out that only a careful synthesis of all signs can give a univoque answer, may be doubtful but never wrong. It is suggested from the personal experience that radioisotope cisternography is better suited for judging the state of compensation of an hydrocephalus. Radioisotopes do that without undue risks. It may be but one good reason for explaining the annual decrease in the number of pneumo-encephalographies (PEG) registered almost everywhere in the world. Other factors may be involved. No doubt that PEG has lost its first place in the study of patients who may have some kind of non tumoral hydrocephalus.