Neuroimaging clinics of North America
-
In adults, the most common expansile "mass" lesion in the posterior fossa is a subacute stroke, whereas the most common neoplastic lesion in the posterior fossa is cerebellar metastasis (intra-axial) or vestibular schwannoma (extra-axial). Those diseases fall outside the scope of this article, which focuses on primary intra-axial tumors of the posterior fossa in adults. This category of tumors is uncommon and more frequently encountered in children. This article reviews tumors of the cerebellum, brainstem, and fourth ventricle that are seen in adult patients, following categories from the 2007 World Health Organization classification of central nervous system tumors.
-
This article presents a summary of advanced MR imaging techniques and their use in the evaluation of patients with brain tumors. It reviews diffusion-weighted imaging, diffusion-tensor imaging, T2* susceptibility-sensitive imaging, MR spectroscopy, MR perfusion, and functional MR imaging, and discusses their current roles in the evaluation of patients with brain tumors.
-
Primary central nervous system lymphomas are aggressive, high-cell-density tumors. There is recent increase in their incidence in immunocompetent patients. ⋯ Moreover, information obtained from advanced MR imaging techniques, such as diffusion-weighted imaging, diffusion tensor imaging, MR spectroscopy, perfusion-weighted imaging, and dynamic contrast-enhanced studies, increases diagnostic confidence and helps distinguish them from other aggressive intracranial tumors. This article discusses typical imaging findings of primary and secondary central nervous system lymphomas on computed tomography and conventional MR imaging, advanced MR imaging techniques, and changes related to steroid therapy.