• Many causes including hypertension, infarction, underlying malignancy, arteriovenous malformation, cerebral amyloid angiopathy, drug abuse, etc
• Highly vascularized malignant primary brain tumors tend to bleed spontaneously and should always be included in the differential diagnosis of nontraumatic intracerebral hemorrhage
• Up to 10% of patients with a brain tumor can experience a diagnostic delay if CT is the only imaging modality

• Variable depending on the underlying etiology

• Symptoms
  • Headache, sensorimotor deficits, altered mental status, herniation syndromes
• Age and gender
  • Variable depending on the underlying etiology
• Prognosis
  • Related to location and size
  • Approximately 25% of patients die within the first 48 hours

• General
  • Round, oval, or irregular
  • Location varies with etiology
    • Hypertension: striatocapsular > thalamus > pons and cerebellum
    • Thrombosis: follows arterial or venous territories
    • Amyloid: peripheral/lobar
    • Malformations and malignancies: any location
• Modality specific
  • CT
    • Hyperdense hematoma with surrounding hypodense edema in the acute setting
    • Hematoma becomes less dense with time
  • CTA/CTV
    • Only helpful when thrombosis is suspected
  • MRI
    • Signal characteristics correspond to the age of the blood products
    • Hyperacute (<24 hours)
      • T1 isointense, T2 hyperintense
      • Intracellular oxyhemoglobin
    • Acute (24 hours to 3 days)
      • T1 isointense, T2 hypointense
      • Intracellular deoxyhemoglobin
    • Early subacute (3–7 days)
      • T1 hyperintense, T2 hypointense
      • Intracellular methemoglobin
    • Late subacute (7 days to 3 weeks)
      • T1 hyperintense, T2 hyperintense
      • Extracellular methemoglobin
    • Chronic (>3 weeks)
      • T1 and T2 hypointense
      • Extracellular hemosiderin
    • T2*
      • Often hypointense signal, particularly with hemosiderin deposition
    • Contrast
      • Can demonstrate enhancement if underlying malignancy or vascular malformation
      • Small amount of reactive enhancement can also be present around a subacute hematoma
    • MRA/MRV
      • Helpful when looking for thrombosis
  • Conventional angiography
    • Helpful when looking for thrombosis or underlying vascular malformation
  • Dual-energy CT
    • Can prove useful for rapidly identifying the underlying etiology
    • Many recent studies have demonstrated the utility of dual-energy CT for detecting underlying vascular malformations and malignancy in the setting of an intracranial hemorrhage
• Imaging recommendations
  • Start with NECT
    • If etiology is clear from history, no need for further imaging
    • If unclear, recommend CTA to evaluate for underlying vascular malformation or thrombosis
  • MRI with contrast and T2* sequence
    • If CT negative or etiology unclear
    • If a vascular etiology is suspected, recommend CTA, MRA, or MRV
  • Recommend follow-up MRI or DSA if etiology remains unclear, because a recent hematoma could mask an underlying tumor or vascular lesion
  • Dual-energy CT can be a useful tool for detecting underlying tumors in patients with an intracranial hemorrhage of unknown origin
• Mimic
  • On initial imaging, it can be difficult to distinguish bland hematoma from a vascular malformation or hemorrhagic neoplasm. If initial MRI or angiography is not helpful in delineating the underlying etiology, follow-up MRI or conventional angiography might be necessary. More recent studies suggest that initial evaluation with dual-energy or spectral CT could help identify the underlying etiology.

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Sean Dodson, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.02.10