The Society of Neurological Surgeons
• Identify basic intracranial structures
• Identify brain shift, intracranial hemorrhage, and skull
• Be able to communicate accurately to the chief resident or
attending the important findings that may impact clinical
decision making and emergent patient management.
Bone Window Soft Tissue Window
Mastoid air cells
• 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
• 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
• Epidural Hematoma (EDH)
• Subdural Hematomas (SDH)
• Subarachnoid Hemorrhage (SAH)
• Intracerebral Hemorrhage (ICH)
• Intraventricular Hemorrhage (IVH)
– 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
– 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
• More likely to be “crescent shaped” than
• 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
Acute Subacute Chronic
• 50% without significant history of trauma
• Hypodense/isodense crescent shaped
• Evacuate if symptomatic
• Looks like motor oil
• Often occurs in the elderly on aspirin, plavix,
• Can be treated by twist drill craniostomy,
burr hole or craniotomy
ACoA Aneurysm Perimesenchephalic Diffuse SAH
55 year old male, fell off ladder,
Traumatic SAH no LOC, mild headache
Repeat head CT stable, discharged next day with routine
• Hypertensive IPH
– 50% in basal ganglia
– 15% thalamus
– 10-15% pons
IPH, IVH, Acute Hydrocephalus
Lobar Intracerebral Hemorrhage:
Frontal Horn Temporal Horn Lateral Ventricle
Aneurysmal SAH w/ IVH HTN w/ IVH
• 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
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
7 year old boy
EVD placed, immediately better
• 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
Infarct with a Midline Shift
• Loss of Grey/White Differentiation
• Cisternal Effacement
• Midline Shift
• Vasogenic: from
– BBB disrupted
– Responds to
• Cytotoxic: from
– 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
• Open Depressed
• Basal Skull Fracture
Depressed 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
• Not based on density
• Objects are described in terms of intensity (hypointense,
• T1 and T2 Weighted Imaging
• T1 Post Contrast Enhancement
T1 Weighted Image of the Normal
T2 Weighted Image of the Normal
MRI: Views in different planes
Axial Sagittal Coronal
T1 Post Gadolinium Image of a
Diffuse Axonal Injury (DAI)
Magnetic Resonance Imaging: Stroke
• Diffusion Weighted Imaging:
– Cytotoxic edema
– Increase in signal as soon as 5-10 minutes after
Right: ADC map