Subcortical Injury

KEY FACTS

TERMINOLOGY

• Subcortical injury (SCI): Deep diffuse axonal injury lesions of

brainstem, basal ganglia, thalamus, and regions around 3rd

ventricle

• Intraventricular hemorrhage (IVH): Hemorrhage within

ventricular system

• Choroid hemorrhage (CH): Hemorrhage localized to

choroidal plexus

IMAGING

• SCI: FLAIR most sensitive → hyperintense foci

• IVH: Hyperdense intraventricular blood; fluid-heme level

common

• CH: Localized hyperdense choroidal hemorrhage

TOP DIFFERENTIAL DIAGNOSES

• SCI: Cavernous malformation, lacunar infarcts, small-vessel

ischemia

• IVH: None

• CH: Normal calcification may mask small hemorrhages

PATHOLOGY

• SCI: Most commonly induced by shear-strain forces that

disrupt penetrating &/or choroidal vessels

• IVH: Disruption of subependymal veins

• CH: Traumatic shear forces damage to choroid tissue

CLINICAL ISSUES

• SCI: Profound neurologic deficits

• IVH: Obtundation, seizures

• CH: Can lead to IVH

DIAGNOSTIC CHECKLIST

• Delayed development of deep lesions common

○ Initial scan may show only diffuse brain swelling

○ Focal lesions often appear 24-48 hours later

• Remember: The deeper the lesion, the more severe the

injury

(Left) Initial axial NECT in a

17-year-old girl involved in a

high-speed MVA demonstrated

only diffuse brain swelling (not

shown). Because of persisting

low GCS, repeat scan was

obtained 24 hours later,

showing a focal midbrain

hemorrhage ſt. (Right) More

cephalad scan shows a

punctate hemorrhage in the

right fornix ſt and in the 3rd

st and lateral ventricles ﬇.

The patient expired 1 week

later. The presence of deep

lesions and intraventricular

hemorrhage indicate severe

subcortical injury.

(Left) Axial NECT in a patient

with subcortical injury shows a

hyperdense choroidal

hemorrhage within choroid

plexus substance of both

ventricles ſt. Note the

subarachnoid hemorrhage ﬊,

corpus callosum diffuse axonal

injury (DAI) ﬇, left caudate

hemorrhagic DAI st, and a

ventriculostomy tube tip ﬉.

(Right) Axial T2WI MR in the

same patient shows

hypointense hemorrhages

distending the choroid plexi

ſt. A left caudate

hemorrhagic DAI st is again

seen.

Trauma, and Stroke

Brain: Pathology-Based Diagnoses: Malformations,

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