Table 2 Imaging characteristics for diagnosis of radiation necrosis

MRI

-Contrast enhancement pattern (soap bubble or Swiss cheese pattern, etc.),

-Location of enhancement (periventricular, corpus callosum, midline crossing, subependymal spread),

-Multiplicity (single/multiple),

-Distance from primary tumor site (ipsilateral/contralateral)

MRS

-Decreased peaks in Cho, NAA and Cr,

-Low Cho/Cr values

-Elevated Lip-Lac/Cho

PET

-No uptake of radionuclides