Brain ct interpretation.pdf

In The Name of GOD
Dr. Aidin Shakeri
Assistant proff.
Neurosurgery Department
AUMS
Reading the Brain CT

Intruduction
Inside of the body

Intruduction
 X_Ray And Radiograhy

Intruduction
CT Scan, History
1972, Sir Geoffrey Hounsfield and Coworkers
Gradually Advancements in Availability, Speed,
Physiologic Assesments, Reconstruction, Safety

Intruduction
CT Scan in neurologic Field
First Screening tool for Diagnosis of Intracranial pathologies
After :
 Acute loss of consiuosness (seizure ,…)
 any acute neurologic deficite Specially in emergency
situations(weakness, …)
 Severe and new onset headach
 Craniofacial Trauma
 Follow up Assesments
 Post operation Assesments
 Contraindacation of MRI

Intruduction
Technique
 Source
 Detector
 Computer(to voxel)
 Tomography

Intruduction
Technique, Hounsfield Unit
Attenuation coefficiant

Intruduction
Technique, Hounsfield
CT Windowing

Intruduction
Technique
 Patient Position
 Head position
 Interval
 Slice Thickness
 Orbitomeatal

Intruduction
CT Scan , Advantages
1.CT scanning is painless, noninvasive and accurate.
2.Unlike conventional x-rays, CT scanning provides
very detailed images of many types of tissue as well as
the lungs, bones, and blood vessels at the same time.
3.CT examinations are fast and simple; in emergency
cases, they can reveal internal injuries and bleeding
quickly enough to help save lives. unlike MRI. useful for
children and the elderly
4.CT has been shown to be a cost-effective imaging tool
for a wide range of clinical problems.

Intruduction
CT Scan , Advantages
5.CT may be less expensive than MRI. In
addition, it is less sensitive to patient
movement.
6. CT can be performed if you have an
implanted medical device of any kind, unlike
MRI.
7-CT imaging provides real-time imaging.
8-Neuronavigation
9-Ct Guided Biopsy

Intruduction
CT Scan , Disadvantages
1.There is always a slight chance of cancer from radiation.
However, the benefit of an accurate diagnosis far
outweighs the risk.
2.The effective radiation dose from this procedure is about
0.6-10 mSv, which is about the same as the average person
receives from background radiation in eight months until 3
years.
3.Women should always inform their physician or x-ray
technologist if there is any possibility that they are
pregnant.
4.CT scanning is, in general, not recommended for
pregnant women because of potential risk to the baby.

Intruduction
CT Scan , Disadvantages
5.Nursing mothers should wait for 24 hours after
contrast material injection before resuming breast-
feeding.
6.The risk of serious allergic reaction to contrast
materials that contain iodine is rare, and radiology
departments are well-equipped to deal with them.
7.Children should have a CT study only if it is essential
for making a diagnosis and should not have repeated
CT studies unless absolutely necessary.
8.Weakly Identify Posterior fossa pathologies

Intruduction
CT Scan Types
 Axial Brain CT Scan Without Contrast

Intruduction
CT Scan Types
 Axial Brain CT Scan With Contrast
 100 cc-200 cc iodinated Contrast material
 Catheter 18-20 G
 Iv contrast is given to better evaluate:
Vascular structures
Tumors
Sites of infection
 Relative contraindications:
Allergy, renal failure

Intruduction
CT Scan Types
 Brain CT Angiography
 Submilimeter slice,reconstructionable
 Relatively noninvasive Imaging of Great
Head and Neck vasculature
 Intravenous inj.
 Alternative for Conventional
Angiography (complication)
 Diagnose of vascular malformation
 Preoperation Planing(Hypervascular
tumor or vascular encasement)

Contrast
 Specification,
 Metrizamide
 Iohexal(ominipaque)
 Iodixanol(visipaque)
 Iopromide(Ultravist)

Brain Perfusion CT Scan
 Physiologic Data
 Contrast inj
 Imaging during a minute
 “Time- Density” Curve for each Voxel
 CBF(ml/min/100gr)
 MTT(min)
 CBV(cc/100gr)
 Use in Acute Cerebral Stroke

Anatomy
Skull Base , Cranial Fossa

Anatomy
Cranium Coronal Section

Anatomy
Veins And Venous Sinuses

Anatomy
Cisterns
 CircumMesencephalic Cistern
around midbrain, effaced first with ICP raising
and herniation Syndromes
 Suprasellar Cistern
Star-shape above sella, contains circle of willis
 Quadrigeminal Cistern
W- shape at top of midbrain, effaced with Central
herniation
 Sylvian Cistern
Between Frontal and Temporal Lobes

Anatomy
Blood Brain Barrier
 Types Of Edema
 Vasogenic
 Cytotoxic

Brain CT Scan Reading
 Now………

 Normal CT
Center to Out
Problem Oriented
 Pneumonic “Blood Can Be Very Bad”
“Blood, Cistern , Brain , Ventricle , Bone”

(……)
 25cc
 5mm MLS
 Cushing triad
 Head elevation

Blood
 Localization

Blood
 Attenuation Coefficient
 Acute : 70 HU (Globin and Hem)……..1w
 Sub Acute : 30-45 HU ……..1-2 wk
 Chronic : <30 HU……..2-3 wk

Blood
 Epidural Hematoma
 15mm,30cc

Blood
• Epidural Hematoma

Brain CT Scan Reading…
Blood
 Subdural Hematoma
 10mm,5mm MLS

Blood
 Intracerebral hematoma(or Intraparenchimal hematoma)
 Trauma
 Amyloid Angiopathy
Avm
Aneurysm
Tumor
 25cc-50cc

Blood
 Intracerebral hematoma(or Intraparenchimal hematoma), Due to
Cerebral Venous Thrombosis

Blood
Intracerebral hematoma(or Intraparenchimal hematoma) Due to
Hypertention
Basal ganglion
thalamus
Cerebellum
Brain stem

Blood
 Intracerebral hematoma(or Intraparenchimal
hematoma),(globe~25mm)

Blood
 Contusion

Blood
 Sab Arachnoid Hematoma

Blood
 Intraventricular Hematoma

Cistern
 Importance( Effacement, Hematoma)

Cistern ( Normal)

Cistern
SAH
GCS

Cistern
 Normal ~ Elevated Intracranial Pressure

Brain ( Normal )
Gray matter_white matter Differentiation
Symmetry
Sulcuses
Midline Shifting(5mm)

Brain ( Normal )

Brain ( Midline Shift )

Brain
 ICH

Brain
 Vasogenic Edema

Brain
 Ischemic Stroke
(with ischemic edema)

Brain
 Tumors

Brain
 Tumor

 Abscess

Brain
 Cyst

Brain

Brain
 Diffuse Axonal Injury

Ventricles
 IVH

Ventricles
 Hydrocephalus

Ventricles
 Compression and Shifting

Bone , Skull Sutures
 Coronal S.

Bone Skull Sutures
 Sagittal S.

Bone Skull Sutures
 Lambdoid S.

Bone
 Linear skull Fractures

Bone
 Fractures of Skull base

Post Operation Changes in
Cranial Ct Scan
 External Ventricular Drainage

Cranial Ct Scan
 Burr Hole Craniostomy

Cranial Ct Scan
 Craniotomy & Cranioplasty

Cranial Ct Scan
 Craniectomy

Cranial Ct Scan
 Cranioplasty

Cranial Ct Scan
 Ventriculoperitoneal Shunting

Cranial Ct Scan
 Anurysm Clipping

Cranial Ct Scan
Endovascular Interventions

Partial Volume Effect
(volume Averaging) Artifacts

Normal Calcification
 Habenular Commissure
 Pineal Gland

Brain ct interpretation.pdf

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Brain ct interpretation.pdf