Myodil Basal Cisternography—（cerebellopontine- and prepontine cisterns）

MYODIL BASAL CISTERNOGRAPHY:CEREBELLOPONTINE-AND PREPONTINE CISTERNS

Ｉ．緒言

　1963年Baker^1），　Gass^5）等によってpositive contrast　mediumによる後頭蓋窩のクモ膜下槽撮影，いわゆるcisternographyは聴神経腫瘍等の後頭蓋窩の腫瘍性病変の確定診断に非常に有効であることが報告された。以来，Scanlan^8），　Britton^3），　Hitselberger^7），　Stitt^10）等によつてもこの方法が特に聴神経腫瘍の診断に有力であることが証明された。Baker^2）は既に1400余例の検索から180例の腫瘍性病変を経験している。我が国に於いても今日多くの施設で行なわれていると思うが，未だこれに関するまとまつた報告はみないようである。我々は過去2年間，この方法をMyodil Basal Cisternography （以下MCGと略す）と名付け，後頭蓋窩に病変があると思われる症例に応用して小脳橋角部腫瘍10例，内耳孔動脈瘤1例　髄液耳漏1例で陽性所見を得た。さらにこれ等のレ線所見を手術所見を比較することによりこの方法の価値を確かめることができた。本稿では各症例の紹介を中心にして，若干の問題点を挙げてみたい。

Posterior fossa myelography with positive cont-rast medium was designed by Baker (1963) and Gass (1963) respectively to demonstrate lesions of the craniospinal junction and in the cerebello-pontine cisterns. It is now used principally for demonstrating an acoustic neurinoma and is con-sidered to be the most reliable radiological exa-mination for revealing cerebellopontine angle tumors.

In this study we used 3 ml of Myodil (Iophendy-late injection) to examine the cerebellopontine cis-terns and 9 ml for revealing the prepontine cistern, naming this technique Myodil basal cisternography(MCG). Positive results were obtained in 12 lesions, such as 10 cerebellopontine angle tumors, an aneu-rysm in the porus, and a cerebrospinal fluid otor-rhea. Comparing with the operative findings of these cases, this technique was highly evaluated. However, we could not confirm its superiority over any other radiological examination, because no tumor was so small that only this method was possible to demonstrate it. Since arachnoid adhe-sion prevents Myodil from entering the cerebello-pontine cistern, this examination may not be suita-ble for the earliest detection of tumor recurrence following surgery.

The cerebellopontine cisterns on both sides may be obliterated by relatively large tumor associated with increased intracranial pressure. The import-ance of neurological and laboratory findings was emphasized in avoiding the erroneous diagnosis of bilateral involvement.

Except a patient who complained back and leg ache after a total of 12 ml Myodil injection, there were no immediate or delayed complications over the past 2 years.