Patterns of abnormal brain enhancement

Pachy meningeal Enhancement (Intracranial Hypo tension)

Lepto meningeal  Enhancement 

causes: Menigitis, SAH, Metastases

Gyral Enhancement

–       Vascular: re perfusion of ischemic brain, migraine, PRES, seizures

–       Inflammatory: meningitis, encephalitis

Nodular Cortical and Subcortical Enhancement

–       Hematogenous dissemination of metastatic neoplasms and clot emboli.

Open Ring Enhancement

–       Multiple sclerosis (without mass effect)

–       Tumefactive demyelination (with mass effect)

–       Fluid-secreting neoplasms (with mass effect and occasionally with surrounding vasogenic edema)

Peri ventricular Enhancement

–       Primary CNS lymphoma

–       Primary glial tumors

–       Infectious ependymitis 

Reference : radiographics.rsna.org