脳底部異常血管網（"モヤモヤ"）のComputed Tomography

COMPUTED TOMOGRAPHY IN "MOYA-MOYA": SUMMARY OF 16 CASES

　1）16例の"モヤモヤ"の所見を検討した。precon—trast CTの所見は，脳溝・大脳裂の拡大，大脳皮質の吸収値の低下，軽度の脳室拡大，多発性・両側性の脳内低吸収値域，に要約され，本質的には各種の原因による多発性脳梗塞の所見と同様であつた。

　2）postcontrast CTでは，脈絡叢，中脳周囲，脳梁周囲などに少数例で造影増強をみとめたほか，大脳円蓋面表層あるいは脳内低吸収値域の造影増強はみられず，precontrast CTで萎縮像を示した大脳皮質の増強効果も健常例より軽度であつた。脳血管撮影上の異常血管網に相当すると思われる基底核部の造影増強は16例中7例でみられたが，多くの例でその程度は軽微であつた。脳血管撮影所見と所見とpostcontrast CT所見とのこのような解離の原因につき考察した。

CT findings in 16 patients with "Moya-Moya",13 children and 3 adults, were summarized.

CT was interpreted normal both before and aftercontrast enhancement in one patient. Abnormalitieson the precontrast CT in the remaining 15 caseswere: (1) cortical atrophy, often most severe inthe frontal lobes on both sides, (2) slight to moderateventricular dilatation, and (3) intracerebral lowdensity foci which were often multiple and bi-lateral.

After contrast enhancement, no significant in-crease in the attenuation value was observed inand around the intracerebral lucent foci. An ab-normal contrast enhancement was occasionallyfound in the perimesencephalic and pericallosalregion as well as within the choroid plexi of thelateral ventricles, but not in the cortical ribbonover the cerebral convexity surface. An increasein density of the basal ganglia was found in 7patients, but the increase was disappointingly slightwhen the dense vascular nets opacified by angio-graphy was considered. The reason (s) for suchdissociation between the CT and angiographicfindings was briefly discussed.