NMR-CTによる小脳橋角部病変の診断

VISUALIZATION OF CEREBELLOPONTINE ANGLE LESIONS BY NUCLEAR MAGNETIC RESONANCE IMAGING

　抄録　小脳橋角部病変の症例を中心に，東芝製全身用NMR-CT試作機使用の初期経験を報告した。X線CTと比較した場合，その特長としては，①骨によるartifactのないこと，②灰白質—白質のコントラストのよいこと，③種々の断層面の得られること，が挙げられた。また，短所としては，①骨に関する情報に乏しいこと，②血管に関する情報に乏しいこと，③検査時間が長いこと，が挙げられた。

　NMR-CTは，今後，より高能率の機種も開発されると思われる。NMR-CTの臨床診断機器としての有用性を論ずるには，さらに詳細な基礎的研究と症例の蓄積が不可欠であるが，NMR-CTのしかるべき普及と正しい利用をのぞみたい。

The preliminary results from the clinical use a prototype whole body nuclear magnetic resonance (NMR) machine constructed by Toshiba Inc. are presented.

Cranial NMR scans were performed on more than 30 cases with broad spectrum of neurologic diseases using saturation-recovery and inversion-recovery sequences with a field strength of 1500 Gauss. Selective excitation sequence was used for the slice selection and filtered backprojection was used to reconstruct the images. They were dis-played on a 256×256 matrix as 12 mm thick sec-tions. Data aquisition time varied between 3 and 12 minutes. Our initial experiences with six cases harboring cerebellopontine angle lesions discolsed advantages and disadvantages of NMR imaging in comparison with X-ray CT. The advantages were the absence of linear artifacts from the surroun-ding bone, the marked gray-white matter differen-tiation, and the variety of tomographic planes available. The disadvantages included the lack of bone detail, the lack of visualization of the major intracranial vessels, and the long time required for scanning (several minutes per slice).

Although much continued evaluation is neces-sary, NMR seems to have vast potential as a diagnostic tool.