Emergency Cranial
Radiological Assessment
The Society of Neurological Surgeons
Bootcamp
Objectives
• Identify basic intracranial structures
• Identify brain shift, intracranial hemorrhage, and skull
fractures
• Be able to communicate accurately to the chief resident or
attending the important findings that may impact clinical
decision making and emergent patient management.
CT Scan
Bone Window
Soft Tissue Window
Foramen ovale
Foramen spinosum
Carotid canal
Jugular fossa
Mastoid air cells
Sphenoid sinus
Carotid canal
Cisterns
Suprasellar
Interpeduncular
Ambient
Caudate
Internal capsule
Thalamus
Choroid Plexus
CT Scan
• Computerized Axial Tomography or CT scan is the most often used
emergency imaging study in neurosurgery. A CT scan is an excellent study
for identifying intracranial hemorrhage and skull fractures.
• Calcified structures such as bone or the pineal gland appear white or
hyperdense.
• Acute blood clot appears white or hyperdense. Chronic hematomas
appear dark or hypodense.
• Ischemic strokes are hard to identify on CT until they are about 6 – 12
hours old.
Hematomas
•
•
•
•
•
Epidural Hematoma (EDH)
Subdural Hematomas (SDH)
Subarachnoid Hemorrhage (SAH)
Intracerebral Hemorrhage (ICH)
Intraventricular Hemorrhage (IVH)
Epidural Hematoma
– Between the skull and the dura.
– Biconvex or lens shaped.
– More common in children and young adults.
Uncommon in the elderly since the dura is very
adherent to the skull.
– Over 90% are associated with a skull fracture.
Classically due to laceration of the middle
meningeal artery.
– Initial concussion - “lucid interval” - deterioration
– Treatment is usually emergent surgery.
Case Example: 6 year old girl, MVA, GCS 7T, LOC at scene, lucid interval, now
with lethargy and left side weakness
Taken to OR for emergent evacuation of EDH
Acute SDH
• More likely to be “crescent shaped” than
“lens shaped”.
• Often holohemispheric.
• Can extend along falx or tentorium.
• Does not cross the midline.
• Higher morbidity and mortality than EDH due
to additional underlying brain injury.
– 50-90% mortality.
Subdural Hematoma: Clot age and CT
Imaging Characteristics
Acute
Subacute
Chronic
Chronic SDH
• 50% without significant history of trauma
• Hypodense/isodense crescent shaped
collection
• Evacuate if symptomatic
• Looks like motor oil
• Often occurs in the elderly on aspirin,
plavix, or coumadin
• Can be treated by twist drill craniostomy,
burr hole or craniotomy
Subarachnoid Hemorrhage
Subarachnoid Hemorrhage: Pattern
Recognition
ACoA Aneurysm
Perimesenchephalic
syndrome
Diffuse SAH
Traumatic SAH
55 year old male, fell off ladder,
no LOC, mild headache
Repeat head CT stable, discharged next day with routine
follow up
Intracerebral Hemorrhage:
Chronic Hypertension
Intracerebral Hemorrhage
• Hypertensive IPH
– 50% in basal ganglia
– 15% thalamus
– 10-15% pons
IPH, IVH, Acute Hydrocephalus
Lobar Intracerebral Hemorrhage:
Intraventricular Hemorrhage
Frontal Horn
Frontal
Third
Fourth
Temporal Horn
Lateral Ventricle
Occipital
Horns
Intraventricular Hemorrhage
Aneurysmal SAH w/ IVH
HTN w/ IVH
Traumatic Contusions
• Coup or contra-coup contusion
• Hemorrhagic contusions can enlarge or
“blossom” as well as develop extreme
edema, so must follow examination closely
and consider repeat CT scans
• Surgical evacuation if there is excessive mass
effect
47 year old gentleman, was inebriated, fall, LOC,
GCS 7T (E2, M4, V1T), PERRL, In cervical collar
EVD placed, Medical management of ICP, gradually improved over several days,
neck cleared after extubation and improvement in neuro status
18 year old male, shot in head while sitting in car, GCS 15 with no focal deficits,
open scalp wound over skull fracture
Scalp debrided,
bullet fragment
extracted, wound
closed
Acute Hydrocephalus
7 year old boy
with posterior
fossa tumor,
drowsy, less
responsive
through the
day
EVD
EVD placed, immediately better
Ischemic Stroke
• Typically follow a vascular distribution such
as the territory of the MCA, PCA or ACA.
• A stroke may take several hours before it is
apparent on a CT scan.
• Typically is seen earlier on an MRI
MCA Infarcts
Infarct with a Midline Shift
Cerebral Edema
• Loss of Grey/White Differentiation
• Cisternal Effacement
• Midline Shift
Cerebral Edema
• Vasogenic: from
brain tumor
– BBB disrupted
– Responds to
steroids
• Cytotoxic: from
trauma
– BBB closed
– NO steroids
Basal Cistern Effacement
Normal
Tight Swollen Brain
 49 y/o male, MVA
 GCS 3T with fixed/dilated pupils
No improvement, pronounced
brain dead 24 hours later
Fractures
• Linear
• Depressed
• Open Depressed
• Basal Skull Fracture
Depressed Skull Fracture
Open
Depressed
Skull
Fracture
Open
Depressed
Skull
Fracture s/p
MVA
Reconstruction
Basilar
Skull
Fracture
Basilar Skull Fracture of the Temporal
Bone Seen on Bone Windows
Basic Principles of MR Imaging
• Images are created based on signals returning from spinning
protons
• Not based on density
• Objects are described in terms of intensity (hypointense,
isointense, hyperintense)
• T1 and T2 Weighted Imaging
• T1 Post Contrast Enhancement
T1 Weighted Image of the Normal
Brain
T2 Weighted Image of the Normal
Brain
MRI: Views in different planes
Axial
Sagittal
Coronal
T1 Post Gadolinium Image of a
Brain Tumor
Diffuse Axonal Injury (DAI)
Magnetic Resonance Imaging: Stroke
• Diffusion Weighted Imaging:
– Ischemia
– Cytotoxic edema
– Increase in signal as soon as 5-10 minutes after
stroke onset
Left: DWI
Right: ADC map