DW MR Imaging Characteristics of Various Disease Entities

DW MR Imaging Characteristics of Various Disease Entities

	MR Signal Intensity
Disease	DW Image	ADC Image	ADC	Cause
* Relative to that of cerebrospinal fluid (CSF).
† The ADC usually cannot be calculated.
Acute stroke	High	Low	Restricted	Cytotoxic edema
Chronic stroke	Variable	High	Elevated	Gliosis
Hypertensive encephalopathy	Variable	High	Elevated	Vasogenic edema
Cyclosporin toxicity	Variable	High	Elevated	Vasogenic edema
Hyperperfusion after carotid endarterectomy	Variable	High	Elevated	Vasogenic edema
HIV encephalopathy	Variable	High	Elevated	Vasogenic edema
Intraaxial mass
Necrotic center	Variable	High	Elevated	Increased free water
Solid tumor	Variable	Variable	Variable	Depends on cellularity
Arachnoid cyst	Low	High	Elevated	Free water
Epidermoid mass	High	Low*	Restricted*	Cellular tumor
Pyogenic infection	High	Low	Restricted	Viscosity
Herpes encephalitis	High	Low	Restricted	Cytotoxic edema
Creutzfeldt-Jakob syndrome	High	Low	Restricted	Unknown
Diffuse axonal injury
Majority of cases	High	Low	Restricted	Cytotoxic edema
Minority of cases	Variable	High	Elevated	Vasogenic edema
Hemorrhage
Oxyhemoglobin	High	Low	Restricted	Intracellular
Deoxyhemoglobin	Low	Unknown†	Unknown†	Unknown†
Intracellular methemoglobin	Low	Unknown†	Unknown†	Unknown†
Extracellular methemoglobin	High	High	Elevated	Extracellular
Hemosiderin	Low	Unknown†	Unknown†	Unknown†
Multiple sclerosis
Most acute lesions	Variable	High	Elevated	Vasogenic edema
A few acute lesions	High	Low	Restricted	Unknown
Chronic lesions	Variable	High	Elevated	Gliosis, neuronal loss

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