Intracerebral hemorrhage

Last revised by Rohit Sharma on 24 Sep 2022

An intracerebral hemorrhage, or intraparenchymal cerebral hemorrhage, is a subset of an intracranial hemorrhage and encompasses a number of entities that have in common the acute accumulation of blood within the parenchyma of the brain. The etiology, epidemiology, treatment and prognosis vary widely depending on the type of hemorrhage, and as such, these are discussed separately.

They are most often broadly divided according to whether they are spontaneous (primary) or due to an underlying lesion (secondary), and then further divided according to etiology and/or location. 

  1. primary hemorrhages (no underlying lesion)
  2. secondary hemorrhages (some other lesion complicated by hemorrhage)
    • vascular malformation
    • cerebral venous thrombosis
    • tumor (primary or secondary)

CT is usually the modality first obtained and demonstrates a hyperdense collection of blood, often with surrounding hypodense edema. A number of complications may be present, such as extension of the hemorrhage into other intracranial compartments, hydrocephalus, herniation, etc.

The hemorrhage may be present anywhere, examples including:

A number of CT features can predict the likelihood of hemorrhage expansion and are therefore useful in decision-making and prognosis.

  • non-contrast CT
    • hemorrhage size
      • the volume of an intracerebral hemorrhage can be measured using ABC/2 formula or 3D volumetric software
      • hemorrhage size is considered to be the most reliable independent predictor of ICH expansion
      • hematoma expansion is measured as an increased growth >12.5 mL or volume >33% from the initial CT scan
      • hematomas with a volume of more than 30 mL are more prone to expansion
    • hemorrhage shape
      • intracerebral hemorrhage irregularity is thought to be due to multiple leaking vessels feeding the hematoma
      • hemorrhages with irregular shapes are more prone to expansion
    • hemorrhage density
      • the presence of hypodense or isodense regions within the hyperdense intracerebral hemorrhage represents active bleeding and is called swirl sign
      • when the swirl sign is encapsulated it is termed black hole sign
      • the presence of a relatively hypodense area adjacent to a hyperdense area is termed the blend sign
      • heterogeneous hemorrhage with hypodense foci is more prone to expansion
    • intraventricular hemorrhagic extension​
      • intraventricular hemorrhagic extension occurs due to decompression of the hemorrhage into the low resistance ventricular system, thus; hematomas located in the thalamus, caudate nucleus or pons are more prone to intraventricular extension than lobar hematomas
      • a study has shown that lenticular and lobar hematomas with accompanying intraventricular extension displayed a higher proportion of hematoma expansion 5
  • contrast-enhanced CT
    • active contrast extravasation within hematoma predicts future hemorrhage expansion, this can be observed on CT angiography (CTA) as spot sign and pooling of contrast within the hematoma

Findings depend on the size and age of the bleed (see aging blood on MRI).

With any intracerebral hemorrhage the following points should be included in a report as they have prognostic implications 3:

  • location
  • size/volume
    • the ABC/2 formula is widely used, but there may be more accurate formulas (e.g. 2.5ABC/6, SH/2) and analyzes available, some of which, however, may require the addition of specific software to the standard PACS tools
  • shape (irregular vs regular)
  • density (homogeneous vs heterogeneous)
  • presence/absence of substantial surrounding edema that may indicate an underlying tumor
  • presence/absence of intraventricular hemorrhage
  • presence/absence of hydrocephalus
  • when CT angiography is performed, the presence/absence of the CTA spot sign or a vascular malformation

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Cases and figures

  • Case 1: ICH (on warfarin)
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  • Case 2: basal ganglial bleed
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  • Case 3: hemorrhagic infarction
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  • Case 4: hypertensive hemorrhage
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  • Case 5
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  •  Case 6
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  • Case 7: coagulopathy
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  • Case 8: subacute intracranial hemorrhage
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  • Case 9: subacute intracerebral hematoma
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  • Case 10
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  • Case 11: cerebellar
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  • Case 12
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  • Case 13: T2*
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  • Case 14: Hyperacute hemorrhage on MRI and CT
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  • Case 15: spot sign
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