[The diagnosis of cerebellopontine tumours by tomography after positive contrast cisternography (author's transl)].

Forty-one tumours in the cerebello-pontine angle were found as a result of 207 Duroliopaque cisternograms. In all 37 patients who came to operation, the position and size of the tumour, as shown radiologically, could be confirmed. The value of positive contrast cisternography was greatest in the smaller tumours. 35 tumours were less than 2.5 cm. in their vertical diameter. Twenty-four tumours were predominantly extra-meatal, were predominantly extra-meatal, four predominantly intra-meatal and 13 extra- and intra-meatal as well. In only 23 patients was there enlargement of the internal acoustic meatus, either absolutely or by comparison with the other side. In 18 patients there was no significant difference in the meati on the two sides. These facts and the observation that there may be idiopathic meatal widening in the presence of typical symptoms of an acoustic neuroma, but without a tumour being present, underlines the importance of positive contrast cisternography. A high degree of accuracy for tumour less than 2.5 cm. can only be obtained by using the method in conjunction with multi-dimensional tomography.