Cerebral Contusion


KEY FACTS

Terminology

  • Brain surface injuries involving gray matter and contiguous subcortical white matter

Imaging

  • Best diagnostic clue: Patchy hemorrhages within edematous background

  • Characteristic locations: Adjacent to irregular bony protuberance or dural fold

  • Anterior inferior frontal lobes and anterior inferior temporal lobes most common

  • FLAIR: Best for hyperintense cortical edema and subarachnoid hemorrhage

  • GRE: Hypointense hemorrhagic foci “bloom”

  • Best imaging tool

    • CT to detect acute hemorrhagic contusions, other intracranial lesions, and herniations

    • MR to detect presence and delineate extent of lesions

  • Coup: Direct injury to brain beneath impact site

  • Contrecoup: Injury opposite impact site; usually more severe than coup

Top Differential Diagnoses

  • Infarct

  • Venous sinus thrombosis

  • Cerebritis

  • Low-grade neoplasm

  • Transient postictal changes

Pathology

  • Inflammation → worsening/enlarging lesions

Clinical Issues

  • Initial symptom: Confusion → obtundation

  • Central goal: Prevent and treat secondary injury

  • Mass effect and herniation may require evacuation

Coronal graphic illustrates the pathology of closed head injury. Note the hemorrhagic foci involving gray matter of several contused gyri
, axonal and deep gray injuries, and traumatic subarachnoid hemorrhage
in the basal cisterns and sylvian fissure.

Graphics depict the most common sites of cerebral contusions in red. Less common sites are shown in green. The most common locations of all are the anteroinferior frontal and temporal lobes.

Gross pathology of the brain from a patient who died from a severe closed head injury shows bifrontal, temporal hemorrhagic contusions
, as well as traumatic subarachnoid hemorrhage in the suprasellar cistern
.

(Courtesy R. Hewlett, MD.)

NECT scan shows extensive frontotemporal contusions
and traumatic subarachnoid hemorrhage
in a patient with severe brain injury.

TERMINOLOGY

Definitions

  • Brain surface injuries involving gray matter and contiguous subcortical white matter

IMAGING

General Features

  • Best diagnostic clue

    • Patchy hemorrhages within edematous background

  • Location

    • Characteristic locations: Adjacent to irregular bony protuberance or dural fold

      • Anterior inferior frontal lobes and anterior inferior temporal lobes most common

      • 25% parasagittal (“gliding” contusions)

    • Less common locations

      • Parietal/occipital lobes, posterior fossa

    • Coup: Direct injury to brain beneath impact site

    • Contrecoup: Injury opposite impact site; usually more severe than coup

  • Morphology

    • Early: Patchy, ill-defined, superficial foci of punctate or linear hemorrhage along gyral crests

    • 24-48 hours: Existing lesions enlarge and become more hemorrhagic; new lesions may appear

    • Chronic: Encephalomalacia with volume loss

    • Multiple, bilateral lesions in 90% of cases

CT Findings

  • NECT

    • Early: Patchy, ill-defined, low-density edema with small foci of hyperdense hemorrhage

    • 24-48 hours

      • Edema, hemorrhage, and mass effect often increase

      • New foci of edema and hemorrhage may appear

      • Petechial hemorrhage may coalesce

    • Chronic

      • Become isodense, then hypodense

      • Encephalomalacia with volume loss

    • Secondary lesions

      • Herniations/mass effect with secondary infarction

      • Hydrocephalus due to hemorrhage

  • Perfusion CT

    • More sensitive than NECT in detection of cerebral contusions (87.5% vs. 39.6%, respectively)

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