転移性脳腫瘍のCT像

COMPUTED TOMOGRAPHY IN BRAIN METASTASES

　抄録　転移性脳腫瘍50例計116腫瘤のCT像を検討した。CTで脳病巣が単一の例は手術あるいは剖検にて確認したものに限つた。全例にplain CT　とcontrast CT　を行つた。原発巣は肺癌22例，乳癌8例，大腸癌5例，腎癌3例，悪性絨毛上皮腫2例，鼻咽頭癌3例，胃癌1例，食道癌1例，卵巣癌1例，原発不明4例（組織で腺癌）であつた。転移部位は皮質と白質の境界部に多く（82％），Plain CT　で　high density33％，isodensity43％，low densityのものが24％に見られた。high densityで出血を伴つていたのは悪性絨毛上皮腫2例，腎瘤1例であつた。Peritumoral lowdensity （PLD）は93％に見られ白質に限局し，PLDの範囲は腫瘍そのものの範囲より大きい例が多かつた。Contrast CTでring enhanementは35％に見られた。

　CTで脳腫瘤が多発性に認められる場合，転移性腫瘍の診断は容易であるが，単一腫瘤の場合は原発性脳腫瘍との鑑別が困難なことが少くなくない。この時は，胸部写真がその鑑別に役立つことが多い。

CT scan of the one hundred and sixteen metas-tatic brain tumors in 50 patients was reviewed and compared to the previous reports.

The most common primary organ was lung (43%) followed by breast (18%), colon (10%) and kidney (6%). Solitary nodule was found in 20 patients (40%). On plain CT scan, tumor nodules were demonstrated as slightly high density in 38 (33%), isodensity in 50 (43%) and slightly low density in 28 (24%). Majority of tumor nodules were present in the corticornedullary junction (82%).

Brain edema seen as a peritumoral low density was extensive in comparison with the edema in the glioma of the similar size.

On contrast CT scan, ring like enhancement was seen in 41 (35%).

Intra-tumoral bleeding was shown in 2 metastatic nodules from c'mriocarcinoma and in one metasta-tic nodule from renal cell carcinoma, All 3 cases were proved by surgery or autopsy.