聴神経腫瘍ならびに小脳橋角部腫瘍のCT scan—聴神経腫瘍の臨床的ならびに文献的考察（その4）

CTSCAN OF ACOUSTIC NEURINOMA AND THE OTHER CEREBELLOPONTINE ANGLE TUMORS: A CLINICAL OBSERVATION AND REVIEW OF LITERATURE ON ACOUSTIC NEURINOMA (4)

　I．緒言

　CT scanは近年，頭蓋内疾患の診断上，大きな偉力を発揮してきている。聴神経鞘腫（聴神経腫瘍）の診断に際してもCT scanはきわめて有用である。著者ら^6）はすでに本邦・耳科領域において，最初の聴神経鞘腫のCT scan像を呈示し，その有用性の一端について報告した。

　本編では小脳橋角部腫瘍，ことに聴神経鞘腫に"的"をしぼつて，そのCT scan像などについて臨床統計的観点から検討を行なつた。

　Clinical observation and review of literatures on the CT scan of cerebellopontine angle tumors, especially acoustic neurinoma were made.

　Plain CT scans were done on 11 cases of acoustic neurinomas, and positive scans were obtained in 4 cases. Three of these cases had low absorption abnormality. Only one case had a slightly higher absorption abnormality than adjacent normal brain. The remaining 7 tumors were not visualized on plain CT scans. The displacement of the fourth ventricle was recognized in only 2 cases.

　Contrast enhanced CT scans were obtained on 11 cases, and all cases showed positive scans (100%) for increased absorption in the appropriate cerebellopontine angle.

　Contrary to the findings described above, in 3 cases of epidermoids a low density areas which was not enhanced by CT scan was visualized, and 2 cases of meningioma showed high density area on plain CT scan.