MRI in central nervous system infections: A simplified patterned approach

Table 1 This differentiation is aided by diffusion and perfusion sequences

	Diffusion	Perfusion
Infection	Restricted	Increased
Infarction	Restricted	Decreased

Table 2 Role of additional sequences

	T1	T2	T1 + contrast
HIV Encephalopathy	Isointense	Bilaterally symmetrical periventricular white matter hyperintensities	No enhancement
PML	Hypointense	Asymmetrical lesions involving subcortical and periventricular white matter	Faint peripheral areas of enhancement may sometimes be seen

HIV: Human immunodeficiency virus; PML: Progressive multifocal leukoencephalopathy.