13 Cerebellar Masses on Magnetic Resonance Imaging

CLINICAL IMAGAGINGAN ATLAS OF DIFFERENTIAL DAIGNOSIS

EISENBERG

DR. Muhammad Bin Zulfiqar PGR-FCPS III SIMS/SHL

• Fig SK 13-1 Cystic astrocytoma. (A) Sagittal T1-weighted image shows a large cerebellar vermian cyst containing fluid that is more intense than the dilated third ventricle. There is a central nodule of decreased intensity relative to the cerebellum. (B) On the axial T2-weighted image, the cyst fluid is markedly hyperintense. The central nodule has a somewhat lesser signal intensity.24

• Fig SK 13-2 Cystic medulloblastoma. (A) Sagittal T1-weighted image demonstrates a mottled but predominantly hypointense cerebellar vermian lesion compressing the roof of the fourth ventricle. (B) Axial T2-weighted image shows the solid portion of the tumor to be hyperintense, whereas the cystic-necrotic component has an even more marked hyperintensity.24

• Fig SK 13-3 Ependymoma. (A) Sagittal T1-weighted image shows a large hypointense mass (arrows) in an expanded fourth ventricle. (B) Axial T2-weighted image shows the markedly heterogeneous quality of the mass. Note the extension of peritumoral edema into the adjacent cerebellar hemisphere.

• Fig SK 13-4 Hemangioblastoma. (A) Axial postcontrast T1-weighted image shows a mostly cystic left cerebellar lesion with a small nodule (arrow) of enhancement. (B) In another patient, a coronal scan shows a solid and enhancing hemangioblastoma in the left cerebellum.6

• Fig SK 13-5 Cystic hemangioblastoma. Axial T1-weighted scan demonstrates a large cystic mass within the left cerebellar hemisphere. The cyst is markedly hypointense and well marginated and has a nodular component along its medial aspect. Note the virtually pathognomonic appearance of large arteries feeding the solid component of this cystic lesion.24

• Fig SK 13-6 Metastasis. Coronal MR scan after gadolinium administration shows an enhancing right cerebellar lesion with a pronounced mass effect on midline structures.

• Fig SK 13-7 Infarction in the territory of the right posterior inferior cerebellar artery. The well-defined lesion is hypointense on the coronal T1-weighted image (A) and hyperintense on the axial T2-weighted scan (B).

• Fig SK 13-8 Infarction in the territory of the left posterior inferior cerebellar artery. Parasagittal T1-weighted image shows hypointensity of the entire lower half of the cerebellar hemisphere on that side.

• Fig SK 13-9 Resolving hemorrhage. The right cerebellar mass consists of hyperintense methemoglobin surrounded by a thin, hypointense rim of hemosiderin.