수아세포종의 자기공명영상 소견과 병기결정을 위한 뇌척추 조영증강상의 의의

Abstract

PURPOSE: The purposes of this study were to analyze the MR findings of medulloblastoma, and to evaluate thesubarachnoid dissemination and the significance of contrast enhacned MR of brain and spine for tumor staging.MATERIALS AND METHODS: The properative brain MR studies of 18 patients(9 males, 9 females; mean age, 9.4 years)with surgically proved medulloblastomas were retrospectively reviewed to characterize these neoplasms with regardto their location, size, MR signal intensity, appearance after contrast enhancement, presence of cyst andnecrosis, subarachnoid dissemination, and other associated findings. In 14 patients posstoperative spine MRstudies were evaluated for staging and therapeutic planning. RESULTS: The most frequent location ofmedullobalstoma was the inferior vermis and the mean tumor size was 4.1x 3.6 x3.9 cm. On T1-weighted image,medulloblastomas generally had low to intermedidate signal, predominantly hypointense relative to white matter.Inhomogeneous contrast enhancement was demonstrated in 13 patients(72.2%) after injection of gadopentetatedimeglumine(Gadolinium). Cyst and necrosis within the tumor were visualized in 15 patients(83.3%). Subarachnoiddisseminations of medullobalstomas were noted in 11 patients(61.1%), of which 6 demonstrated intracranial and 2intraspinal dissemination. Three had both intracracnial and intraspinal dissemination. In nine cases withintracranial lesions, there were intraparenchymal mass formation(7), subarachnoid nodules(5), infundibularlesions(2) and diffuse gyral enhancement(1). In five cases with intraspinal lesions, there were extramedullaryintradural small nodules(3), central canal nodules(2), intradural masses(1) and fine nodular and sheet-likeleptomeningeal enhancement(1). Other associated findings included intratumoral hemorrhage(11.1%), peritumoraledema(44.4%), tonsillar herniation(44.4%), hydrocephalus(88.9%) and calcificaitaon(44.4%). CONCLUSION:Medullobalstomas revealed low to intermediate signal intensity on T1-weighted image and intermediate to moderatelyhigh signal intensity on T2-weighted image, relative to cerebellar white matter. Medullobalstomas were solidtumors with cystic necrosis, which showed inhomogeneous enhancement and subarachnoid disseminations to theintracranial and intraspinal spacesa after Gd-DTPA enhancement. Gd-enhanced MR of brain and spine was an usefuldiagnostic modality in preoperative diagnosis and in staging of postoperative cases of medulloblastomas. which wassuperior to postcontrast CT or precontrast MR.