Table 3.

Appearance of Aging Blood on MR Sequences

	Time frame	Molecular Species	Celluar compartment	T1WI signal§	T2WI signal††
Hyperacute	<24 h	Oxyhemoglobin	Intracellular	Isointense	Iso-/Hyperintense
Acute	1-3 d	Deoxyhemoglobin	Intracellular	Iso-/Hypointense	Hypointense
Early Subacute	3-7 d	Methemoglobin	Intracellular	Hyperintense	Hypointense
Late Subacute	7-14 d	Methemoglobin	Extracellular	Hyperintense	Hyperintense
Chronic	>14 d
Rim		Hemosiderin	Intracellular	Hypointense	Hypointense
Center		Hemichromes	Extracellular	Isointense	Hyperintense

^§Compared to the signal intensity of normal brain parenchyma.

Adapted from W G Bradley J. MR appearance of hemorrhage in the brain. Radiology 1993;189(1):15-26; with permission.