Head Trauma Imaging
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Transcript of Head Trauma Imaging
HEAD
TRAUMA
IMAGING
Ma. Socorro I. Martinez, MD, FPCR, FUSP, FCT-MRISP
•Role of Skull X-rays - debatable
CT• Imaging procedure of choice for acute injury
or neurologic deficit• Quick, easy, reliable & available• Valuable in making a dx, excluding
alternative diagnoses or sequelae of other pathology
• Px monitoring is simple & safe• compatible w/ px stabilization devices• Identification & localization of calvarial fxs &
bony/metallic fragments • Optimal assessment for acute hemorrhage
& mass effect • Contrast infusion rarely indicated
CT may reveal:
• No abnormality (30%) • Areas of edema (10%) • Hemorrhagic contusion (20%) • Extradural or subdural hematoma
(20%) • Combination of the above (20%)
Epidural hematoma
• may present as primary depressed consciousness or ff a lucid interval
• assoc w/ skull fx (calvarium), not always
• usu temporoparietal• Laceration of dural a. or a venous
sinus (middle meningeal a. or one of its branches)
• bld collects b/n inner table of skull & dura (periosteal layer)
• uniformly hyperdense (acute) well-defined biconvex mass; may contain hypodense foci due to active bleeding
• often w/ significant mass effect (compression of ipslateral lat ventricle & dilatation of opp lat ventricle due to obstrxn of foramen of Monro)
• basal cisterns may be effaced
Subdural hematoma
• b/n dura and arachnoid• from ruptured veins crossing
this potential space• more common in elderly - space
enlarges as brain atrophies
Acute subdural hematoma
• can have equally severe consequences due to mass effect, requiring urgent surgery
• Deceleration and acceleration or rotational forces that tear bridging veins
• CT – Crescent-shaped– Hyperdense, may contain
hypodense foci due to serum, CSF or active bleeding
– Does not cross dural reflections
Subacute Subdural Hematoma • may be difficult to visualize by CT -
becomes isodense to normal gray matter as hemorrhage is reabsorbed
• shift of midline structures w/o an obvious mass (subtle)
• contrast may help- enhancement of dura & adj vascular structures, distinct interface b/n hematoma & adj brain
• - Compressed lat ventricle- Effaced sulci- White matter "buckling"- Thick cortical "mantle"
Chronic subdural • etiol not always clear; prob
due to trauma, often minor• vague symptoms & often dev
slowly w/ gradual depression or fluctuation of consciousness
• bilateral in 10% • becomes low density as
hemorrhage is further reabsorbed
• crescentic, often w/ mass effect
• may be loculated• if w/ rebleeding- mixed density
and fluid/sedimentation levels
Intracerebral HemorrhageHemorrhagic contusion
• stretching & shearing injury• most common primary intra-
axial injury• brain impacts on bony ridge
or dural fold• contre coup - directly opp
impact site, subcutaneous hematoma, fx, or EDH
• common locations:- Temporal lobe - ant tip, inf surface, sylvian region- Frontal lobe - ant pole, inf surface- Dorsolateral midbrain- Inf cerebellum
• CT -ill-defined hypodense area mixed with foci of hemorrhage
• Adj SAH common• After 24-48 hrs –
– hmgic transformation or coalescence of petechial hemorrhages into a rounded hematoma is common
Multiple petechial hemorrhages
• may be throughout cerebral hemispheres
• often very small & at grey/white matter interface
• due to shearing injury w/ rupture of small IC vessels
• in a comatose px w/ no other obvious cause - implies severe diffuse brain injury w/ poor prognosis
• Larger hemorrhages in severe trauma; may not be apparent on immediate scan, becomes prominent after a day or two
• MRI more sensitive, part. in the absence of hemorrhage
Diffuse Axonal Injury • "shear injury“• most common cause of significant
morbidity in CNS trauma• 50% of all primary intra-axial injuries • Acceleration, deceleration and rotational
forces • Immediate loss of consciousness is typical • CT may be normal • CT - ill-defined areas of high density or
hemorrhage• occurs in a sequential pattern of locations
based on the severity of the trauma– Subcortical white matter – Posterior limb internal capsule– Corpus callosum– Dorsolateral midbrain
Subarachnoid hemorrhage • alone or in assoc w/ other
IC or EC hematomas• injury of small arteries or
veins on surface of brain• b/n pia & arachnoid
matter• most common cause of
non-traumatic SAH- cerebral aneurysm rupture
• may also be due to ruptured aneurysm or AVM; may have led to subsequent trauma (imptce of history). Cerebral angio
• TRAUMA -most common cause of SAH
• most commonly over cerebral convexities or adj to injured brain (i.e.cerebral contusion)
• CT- focal high density in sulci and fissures, Sylvian fissure, basal cisterns or ventricular system
• may be complicated by hydrocephalus
Intraventricular Hemorrhage
•assoc w/ DAI, deep gray matter injury, and brainstem contusion
• isolated intraventricular hemorrhage may be due to rupture of subependymal veins
Edema
• Focal edema - localized poorly defined areas of low density– MRI more sensitive
• Diffuse edema - esp in children– may be difficult to detect on CT
Infarction
• Infarction in a typical vascular territory may suggest dissection of a vessel, such as the carotid artery after a direct blow to the neck.
Skull Fractures
• linear (more common) or depressed
• Imptce of bone windows • May involve PNS or skull base• Vs. sutures in anatomical
locations (sagittal, coronal, lambdoidal) and venous channels (undulating margins & sclerotic margins)
• Depressed fractures - inward displacement of fx fragments
Depressed skull fractures
Skull base fractures
• not always visible• blood in sinuses is suggestive• prone to dev meningitis &
require antibiotic prophylaxis• If w/ clinical evidence of skull
base fx (eg CSF rhinorrhoea or bleeding from EAM), a normal CT does not exclude such a fx
Pneumocephalus
• indicates an open head injury, such as due to a basal fracture communicating with sinuses or a penetrating injury to vault (eg a bullet wound)
• indicates the need for antibiotics
Petrous temporal bone fractures
•Transverse ; longitudinal•may be associated with post
traumatic deafness• transverse fracture is more
severe in this respect
Orbital blowout fracture
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