KEY FACTS Terminology Brain displaced from 1 compartment into another Imaging Subfalcine herniation Cingulate gyrus displaced under falx Lateral ventricle compressed/displaced across midline Contralateral ventricle dilated Unilateral descending transtentorial herniation (DTH) Temporal lobe displaced medially into incisura Encroaches on, then…
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…
KEY FACTS Terminology Traumatic axonal stretch injury Imaging General features Can be hemorrhagic or nonhemorrhagic – Microbleeds important imaging marker for diffuse axonal injury (DAI) – Intraventricular hemorrhage correlates with DAI Location – Subcortical/deep white matter (WM), corpus callosum –…
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…
KEY FACTS Terminology Blood within subarachnoid spaces Contained between pia and arachnoid membranes Imaging High density on CT, hyperintensity on FLAIR Top Differential Diagnoses Nontraumatic SAH Meningitis: Cellular and proteinaceous debris Carcinomatosis meningitis Pseudosubarachnoid hemorrhage Gadolinium administration High inspired oxygen…
KEY FACTS Terminology Intentionally inflicted injury; abusive head trauma, inflicted head injury, nonaccidental head injury Imaging Plays key role in early diagnosis Disparate brain injuries relative to proffered history Skeletal survey, NECT as initial primary imaging tools Detection/characterization of intracranial…
KEY FACTS Terminology “Typical” epidural hematoma (EDH) Arterial laceration 90-95% supratentorial (temporoparietal most common) Biconvex, unilateral Atypical EDH Unusual etiology Unusual location Unusual shape or density Imaging Venous EDH (10% of EDHs) Fracture (linear, diastatic) crosses dural venous sinus Skull…
KEY FACTS Terminology Blood collection between skull and dura Imaging NECT Hyperdense, biconvex, extraaxial collection > 95% unilateral, supratentorial Does not cross sutures unless venous or sutural diastasis/fracture is present Compresses/displaces underlying brain, subarachnoid space Low-density swirl sign: Active/rapid bleeding…
KEY FACTS Terminology Chronic subdural hematoma (cSDH) Chronic (> 3 weeks to months) subdural blood products Mixed chronic and acute hemorrhage is common Imaging Crescent-shaped extraaxial collection Spreads diffusely over affected hemisphere Surrounded by enhancing membranes Often septated, loculated, with…
KEY FACTS Terminology Subacute (~ 3 days to 3 weeks) collection In subdural space (between arachnoid and dura or within inner border cell layer) Partially liquefied clot, resorbing blood products Surrounded by granulation tissue (“membrane”) Imaging Crescent-shaped, iso- to hypodense…