NUSU Radiography and medical
imaging sciences 3rd year
CT Technique
There are four types of ICH:
Epidural hematoma
Subdural hematoma
Subarachnoid hemorrhage
Intracerebral hemorrhage
Extra axial fluid collections Dural Hematoma is additional positive examples
illustrated in the following Figs..
dural hematoma involves a collection of blood under the dura
mater that is caused by trauma to the skull.
This blood pooling causes compression and damage to brain
tissue, resulting in drowsiness or loss of consciousness. This
condition, whether acute or chronic, can be diagnosed
without contrast enhancement with CT.
Types of Extra fluid collections:
1. Subarachnoid hemorrhage(SAH) originate from direct vessel injury, (Usually focal).
2. Subdural hematoma(SDH) Occurs between the dura and arachnoid ,and the common caused due to disruption of the cortical veins
3. Epidural hematoma Located between the skull and dura matter, and the common caused due to laceration of the middle meningeal artery or dural veins. Appearance of Hypodense if (chronic), isodense if (subacute), hyperdense if (acute)
4. Intraventricular hemorrhage commonly due to rupture of
vein blood vessels Can occur from reflux of SAH.
Epidural and Subdural Hematoma
Epidural hematoma
A hematoma is a collection of blood, in a clot or ball, outside
of a blood vessel. An epidural hematoma occurs when blood
accumulates between your skull and the outermost covering
of your brain.
It typically follows a head injury, and usually with a skull
fracture. High-pressure bleeding is a prominent feature. If
you have an epidural hematoma, you may briefly lose
consciousness and then regain consciousness.
What is the Diagnosis ? Epidural Hemorrhage
buildup of blood occurring between the dura mater (the brain's tough outer membrane)
and the skull.
BRAIN STANDARD (Non contrast)
Subdural hematoma
A subdural hematoma is a collection of blood on the surface
of your brain.
It’s typically the result of your head moving rapidly forward
and stopping, such as in a car accident. However, it could also
suggest abuse in children. This is the same type of movement
a child experiences when being shaken.
A subdural hematoma is more common than other ICHs in
older people and people with history of heavy alcohol abuse.
Head trauma
A bone window showed skull fractures, brain window showed subdural hematoma
CT Density 72.9 HU
What is the Diagnosis ?
Subdural hematoma:
• Acute hematoma is seen by non-
contrast imaging as an area of high
density with density numbers
ranging from 40 to 90HU.
Note:
Subdural hematoma is located between
the layers of dura and arachnoid mater,
covering the cerebral hemispheres
72.9 HU
BRAIN STANDARD (Non contrast)
Subdural Hematoma:
• Recognized by CT as crescentic shaped
increased density,
• Subdural hematoma can evolve over a period
of time and thus classified as
acute, sub acute and chronic hematoma.
Acute Subdural Hematoma:
Up to 7 day old High CT density (40-90HU)
Sub acute Subdural Hematoma
7 to 21 days old The CT density of acute blood
gradually decreases and becomes isodense with
adjacent brain, thus less readily visible and can be
easily overlooked.
BRAIN STANDARD (Non contrast)
Chronic Subdural Hematoma:
Over 21days ; Acute blood as it evolves, it
undergoes liquefaction, and also mixes with
cerebrospinal fluid from adjacent subarachnoid
space, thus converting into a serosanguineous fluid.
This fluid has low CT density reaching close or
similar to cerebrospinal fluid.
Slow movement of subarachnoid fluid into the
subdural hematoma can give rise to gradual
expansion of subdural hematoma that can exert mass
effect upon the adjacent brain with or without brain
edema.
BRAIN STANDARD (Non contrast)
Chronic Subdural Hematoma
Acute subdural haematoma
Chronic subdural l haematoma
Subdural hematoma
Acute Subacute Chronic
Subarachnoid hemorrhage
A subarachnoid hemorrhage is when there’s bleeding
between the brain and the thin tissues that cover the brain.
These tissues are called meninges. The most common cause is
trauma, but it can also be caused by rupture of a major blood
vessel in the brain, such as from an intracerebral aneurysm.
A sudden, sharp headache usually comes before a
subarachnoid hemorrhage. Typical symptoms also include loss
of consciousness and vomiting.
What is the Diagnosis ?
Subarachnoid Hemorrhage
Subarachnoid blood is recognized by
visualizing the high-density of acute blood
outlining the cerebral sulci and
subarachnoid cisterns.
Is bleeding into the subarachnoid space
surrounding the brain, the area between the
arachnoid membrane and the pia mater.
BRAIN STANDARD (Non contrast)
Intracerebral hemorrhage
Intracerebral hemorrhage is when there’s bleeding inside of
your brain. This is the most common type of ICH that occurs
with a stroke. It’s not usually the result of injury.
CT Density 68.6 HU
What is the Diagnosis ?
Acute Intracerebral hematoma:
• Acute hematoma is seen by non-
contrast imaging as an area of high
density with density numbers
ranging from 40 to 90HU.
BRAIN STANDARD (Non contrast)
68.6 HU
Note:
• Intracerebral hematoma is localized
within the brain substance.
Stroke
• Terms used to describe stroke in the medical field include
cerebrovascular accident (CVA).
• Stroke may be divided into main categories:
1. ischemic, caused by a blockage in an artery,
2. hemorrhagic, caused by a tear in the artery’s wall that
produces bleeding in the brain.
3. less-prevalent type is hypotensive, which occurs as a result
of blood pressure that is too low.
Hemorrhagic Stroke
Rupture of a blood vessel in the brain causes leakage of blood
into the brain parenchyma, CSF spaces around the brain, or
both.
Infarction
Hemorrhage
Cerebral infarct
Brain Infarct
BRAIN- AXIAL
BRAIN STANDARD (Non contrast)
Normal CT Brain Hydrocephalus
BRAIN- AXIAL
BRAIN STANDARD (Non contrast)
hydrocephalus
Brain Atrophy
Tumors and metastasis
BRAIN- AXIAL
BRAIN STANDARD (with contrast)
Glioma
Cyst – Ring enhancement
PROTOCOLS
BRAIN STANDARD
PITUITARY & SELLA TURCICA
PETROUS TEMPORAL BONE AND INNER EAR
ORBITS
HEAD CT
SCOUT : Lateral
LANDMARK : OML
SLICE PLANE : Axial and Coronal
BREATH HOLD : None
I.V. CONTRAST : 50-80 ml
START LOCATION : 0.5 cm below hypophyseal region
END LOCATION : 0.5 cm above hypophyseal region
SLICE THICKNESS : 2-3 mm
FILMING
Soft tissue (WW140-300 WL 30-40 )
Bone (WW 2000-3000 WL 200-400)
NOTES : Pre and post contrast cuts with the same
plane and filming
PITUITARY & SELLA TURCICA
PITUITARY & SELLA TURCICA
Pituitary tumor
PITUITARY- CORONAL
PROTOCOLS
BRAIN STANDARD
PITUITARY & SELLA TURCICA
PETROUS TEMPORAL BONE AND INNER EAR
ORBITS
HEAD CT
SCOUT : Lateral
LANDMARK : IOML
GANTRY TILT : IOML for axial & according
to patient tilt for coronal.
SLICE PLANE : Axial and Coronal
BREATH HOLD : None
I.V. CONTRAST : None ( Yes for tumors)
START LOCATION : F. Magnum
END LOCATION : Through petrous bone
SLICE THICKNESS :
1-2 mm, 1mm through Canal, 2 mm Petrous bone
FILMING: Soft tissue and Bone window
NOTES : High resolution CT is the recommended
technique for demonstrating the air cells
PETROUS TEMPORAL BONE AND INNER EAR
INTERNAL AUDITORY CANAL
IAC- AXIAL
PROTOCOLS
BRAIN STANDARD
PITUITARY & SELLA TURCICA
PETROUS TEMPORAL BONE AND INNER EAR
ORBITS
HEAD CT
SCOUT : Lateral
LANDMARK : IOML
SLICE PLANE : Axial and Coronal
BREATH HOLD : None
I.V. CONTRAST : None for trauma case
( Yes for tumors)
START LOCATION :
•Axial : Top of max. sinus
•Coronal : Sphenoid sinus
END LOCATION :
•Axial : Upper Orbital Rim
•Coronal : Anterior Globe
SLICE THICKNESS : 2-3 mm
FILMING: Soft tissue and Bone window
ORBITS
ORBITS
If patient can’t assume prone position obtain supine coronal
ORBITS
Coronal cut demonstrates a superior
orbital fracture on the left orbit with
fragments of bone extending toward the
frontal lobe.
Coronal cut demonstrates an infra
orbital fracture ( Right side)
Intracranial CT angiography
most common indication Circle of Willis: Aneurysm
Area scanned: entire brain.
Contrast volume and type: 90 ml of nonionic contrast.
Injection rate: 3ml/sec.
Scan delay: usually 15-20 sec.
Length of spiral (time): 40 sec.
Slice thickness:1 mm.
Pitch 1.
Reconstruction interval: 0.5 mm.
3D technique used: MIP/volume rendering.
Intracranial CT angiography
CT ANGIOGRAPHY (CTA)
Bringing out the information contained in images of CTA
requires review using different perspectives:
1) Maximum intensity projection (MIP)
2) Multiplanar reconstruction (MPR).
3) Volume rendering technique (VRT)
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