Timeline diagram of MRI and CT characteristics of intracerebral hemorrhage

Hyperacute intraparenchymal haemorrhage (within the first hours of the haemorrhage):

• T1w isointense to surrounding brain tissue. There may be seen a slightly hypointense clot forming with a surrounding slightly hyperintense plasma rim.
• T2w isointense to hyperintense to surrounding brain tissue.

Acute intraparenchymal haemorrhage (1 to 2 days):

• T1w signal intensity of the lesion centre remains intermediate-to-low (depending on clot formation).
• T2w signal intensity of the lesion centre drops in comparison to surrounding brain tissue
• increasing perifocal oedema.

Early subacute intraparenchymal haemorrhage (2 to 7 days):

• T1w signal intensity of the core lesion gradually increases, progressing from the outside to the lesion core (Met-Hb leads to T1-time shortening).
• T2w signal intensity of the lesion centre stays low.
• Perifocal oedema.

Late subacute intraparenchymal haemorrhage​ (7 to 14-28 days):

• T1w high signal intensity of quite some part of the lesion periphery or of the complete lesion depending on lesion size (Met-Hb leads to T1-time shortening).
• T2w signal increases.
• Perifocal oedema decreases.
• Dark rim in T2w surrounding the lesion.

Chronic intraparenchymal haemorrhage (>14-28 days):

• T1w low signal intensity of the lesion centre compared to surrounding brain tissue.
• T2w high signal intensity of the lesion centre compared to surrounding brain tissue.
• Dark rim in T2w surrounding the lesion.