MR INTRACRANIAL HEMORRHAGE

HYPERACUTE:  Intracellular oxyhemoglobin. Isointense on T1.  Isointense to Hyperintense on T2

ACUTE (1 TO 2 DAYS): Intracellular deoxyhaemoglobin. T2 signal intensity drops (T2 shortening) T1 remains intermediate-to-low

EARLY SUBACUTE (2 TO 7 DAYS): Intracellular methemoglobin. T1 signal gradually increases (T1 shortening) to become hyperintense.

LATE SUBACUTE (7 TO 14-28 DAYS): Extracellular methemoglobin.Over the next few weeks, as cells break down, extracellular methemoglobin leads to increase in T2 signal

CHRONIC (>14-28 DAYS): Periphery: Intracellular hemosiderin. Low on both T1 and T2. Center: Extracellular hemichromes.  Isointense on T1, hyperintense on T2

Extracranial blood products age differently than intracranial blood products, and extracranial hematomas often have a heterogeneous appearance, confounding attempts at reliably dating the age of an extracranial hemorrhage.  Blood / hemorrhage appears hypointense and blooms black on MRI T2* GRE imaging and also highly sensitive to old hemorrhage to be seen as hemosiderin staining.

I BLEED, I DIE, BLEED DIE, BLEED BLEED, DIE DIE

HYPERACUTE < 24 HRS "I Bleed" T1 Isointense T2 Bright

ACUTE 1 TO 3 DAYS:  I Die T1 Isointense T2 Dark

EARLY SUBACUTE 2 TO 7 DAYS Bleed Die T1 Bright T2 Dark

 LATE SUBACUTE 7 TO 14-28 DAYS: Bleed Bleed  T1 Bright T2 Bright

CHRONIC > 14 TO 28 DAYS:  Die Die  T1 Dark T2 Dark