MRI Late Subacute Hemorrhage

A late subacute hemorrhage refers to a stage of bleeding, particularly observed in brain injuries, that occurs approximately 7 to 14 days after the initial incident. This stage is part of the healing process where blood initially turns from oxyhemoglobin to deoxyhemoglobin and then to methemoglobin, which can be seen in imaging studies.

Grading of Hemorrhages:

Hemorrhages can be classified based on the timing of their occurrence post-injury and their appearance on imaging:

• Hyperacute (first few hours): Fresh bleeding, where blood is primarily oxyhemoglobin. On MRI, hyperacute hemorrhage typically appears isointense to slightly hyperintense on T1-weighted images and isointense to hyperintense on T2-weighted images. 
• Acute (within 1-3 days): Blood converts to deoxyhemoglobin, seen as hypointense to isointense on T1-weighted images and hypointense on T2-weighted images.
• Early Subacute (3-7 days): The presence of intracellular methemoglobin begins and appears bright on T1 MRI images.
• Late Subacute (7-14 days): Intracellular methemoglobin is more prominent and appears hyperintense on both T1-weighted and T2-weighted images
• Chronic (after 2 weeks): Hemoglobin breakdown continues to hemosiderin, with the hemorrhage appearing darker on both T1  scans.

Symptoms of  Hemorrhage

The symptoms of a hemorrhage depend largely on the hemorrhage’s location and size but may include:

• Headache
• Nausea or vomiting
• Increased intracranial pressure
• Neurological deficits such as weakness, numbness, or decreased coordination
• Seizures in some cases
• Altered consciousness or confusion

Diagnosis of Late Subacute Hemorrhage

Diagnosis typically involves imaging techniques that can track the progression of blood breakdown products over time:

• MRI: Most effective for identifying the stage of hemorrhage due to its ability to distinguish between different blood breakdown products.
• CT Scan: Useful for initially identifying hemorrhage and assessing its size and potential effects on surrounding structures.

Treatment

Treatment of late subacute hemorrhage focuses on managing symptoms, preventing complications, and addressing the underlying cause:

• Observation: Close monitoring of the patient’s neurological status and repeat imaging to assess the resolution of the hemorrhage.

• Medication:

  • Antihypertensives: To control blood pressure and prevent further bleeding.
  • Anticonvulsants: To manage or prevent seizures.
  • Pain Management: Analgesics for headache relief.

• Surgery: In some cases, surgical intervention may be necessary to evacuate the hematoma, particularly if there is significant mass effect or if the patient’s condition deteriorates.

• Addressing Underlying Causes: Identifying and treating the source of the hemorrhage (e.g., aneurysm, arteriovenous malformation, or anticoagulant therapy) to prevent recurrence.