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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