Ring-enhancing lesions brain lesions

Diagnosis	CT	MRI						PET
		T1	T2	Gad	DWI	ADC	MRS
primary CNS neoplasm	hypodense with rim enhancement	hypointense	hyperintense	thick rim or nodular enhancement	variable	high	suppressed NAA and creatinine, elevated choline and lactate in high-grade glioma	increased uptake
metastasis	hypodense lesions with rim enhancement	hypointense	hyperintense	thick rim or nodular enhancement	dark	high	suppressed NAA and creatinine, elevated choline and lactate	increased uptake
neurocysticercosis	ring enhancement of capsuile, eccentric dot sign, thin regular outline	core iso to hypointense	core iso to hypointense with hypointense rim	rim enhancement	core hypointense	high	variable	decreased uptake
tuberculoma	hypo or isodense with ring enhancement, irregular outline	`core iso to hypointense	core iso to hypointense with iso to hyperintense rim	rim enhancement, irregular outline	restriction	low	lipid peak	decreased uptake
brain abscess	ring enhancing lesions with surrounding edema; multilobulated lesions may be seen with daughter abscesses	core hyperintense, surrounding hypointense edema	cavity hypointense, surrounding hyperintense edema	ring enhancement	bright	low	lactate, lipids, amino acids, acetate, and succinate peaks	increased uptake
sarcoidosis	ring or nodular enhancing lesions, meningeal or dural enhancement	hypointense	hyperintense	ring or nodular enhancing lesions, meningeal or dural enhancement	variable	variable	non-specific	increased uptake