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iii. Emergency Cranial Radiological Assessment - SNS Society of

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iii. Emergency Cranial Radiological Assessment - SNS Society of Powered By Docstoc
					  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   Diffuse SAH
                syndrome
                              55 year old male, fell off ladder,
Traumatic SAH                 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   Temporal Horn   Lateral Ventricle




 Frontal                               Occipital
 Third                                 Horns
 Fourth
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
                                                       EVD
through the
day




                      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

				
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posted:7/18/2013
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