Intramyocardial hemorrhage

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Intramyocardial hemorrhage is referred to as the extravasation of erythrocytes and/or blood products into the myocardium.

Epidemiology

Intramyocardial hemorrhage occurs in 35-50% of the patients with successful coronary revascularization of ST-elevation myocardial infarction .

Associations

Pathology

Intramyocardial hemorrhage is characterized by erythrocytes and blood products within the myocardium or rather within the myocardial extracellular space. In the setting of myocardial infarction and reperfusion, it is strongly associated with the occurrence of late microvascular obstruction (MVO) .

Etiology

The immediate cause is vascular endothelial damage secondary to the following

  • reperfusion injury
  • cardiac trauma

Radiographic features

MRI

Intramyocardial hemorrhage has been diagnosed in the setting of a hypointense zone surrounded by myocardial edema in T2-weighted and/or STIR images . Hemoglobin and its degradation products are known for their paramagnetic effect and thus influence MR relaxation times .

Signal characteristics

T2/STIR: hypointense

T2* mapping: two cut off values: T2* < 20 [ms] or 2 standard deviations below the mean

T2 mapping: decreased T2 [ms] *

T1 mapping: decreased T1 [ms] *

LGE: hypointense zone within an infarct zone of enhancement, indistinguishable from microvascular obstruction

* sensitivity of T2 mapping and T1 mapping is impaired in an acute setting because of the presence of myocardial edema

Treatment and prognosis

Intramyocardial hemorrhage is a source of residual myocardial iron, which is thought to cause prolonged inflammation and thus adverse remodeling, associated with a poorer prognosis or major adverse cardiac events (MACE).

Differential diagnosis

See also