CT scan in head and spine injuries

BY : DR AHMED MOHAMMED DEBES

رادیولوژی جامع سایت

WWW.RADIOLOGYHA.COM

Brief history

Basic physics

mapped onto Hounsfield scale from –1000 (black) to + 1000 (white).

the brain tissue is the point of reference. Any tissue “whiter” than brain tissue is hyper densewhile any tissue “blacker” than brain tissue is hypo dense

Hounsfield Unitstissue’s attenuation coefficient the ability to “block” X-rays. relatively constant

Image acquisition

LOOK for

I - Skull Fractur

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II – Pneumo-cephalus

III - Hematom

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IV - Cerebral Edema

V - Herniatio

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What to look for in CT scan brain of a head trauma patient ?

I - Skull Fracture

Look in head CT bone window

I - Linear, non-depressed fracture

II - Depressed fractureConsider open when

- Skin laceration over the fracture- Through par nasal sinuses, middle ear structures

Surgical elevation in

- Depressed > 5 mm and overlies motor or speech areas- Depressed > skull thickness

Causes laceration of Dura, arachnoid and possible brain parenchyma

III - Diastatic fracture

Spreading of suture, 1-2 mm more than normal contralateral sideMay tear Dural venous sinus

IV - Basilar fracturePresentations

- CSF otorrhea, bruising over mastoid (Battle sign)- CSF rhinorrhea, bruising around the eyes (raccoon eyes)

II - Pneumocephalus

Presence of air in the cranial cavity

Indicates communication between intracranial and extra cranial spacescomplications: meningitis, CSF otorrhea or rhinorrhea

III - Hematoma

I - Epidural HematomaSource of bleeding

most commonly middle meningeal artery

Don't cross sutures

Hyper dense biconvex extra-axial mass

II - Subdural HematomaSource of bleeding

torn cortical bridging veins

Hyper dense crescent blood collection

Can cross suture

Can extend into interhemispheric fissure

III - Traumatic SubarachnoidHemorrhageSource of bleeding

Tear of veins in subarachnoid space

High density blood in sulci/cisterns

IV - Cerebral Contusiondue to cerebral gyri impact inner table of the skull

Evolve from petechial hemorrhage -> small hemorrhage ->large hematomaMultiple, bilateral

MRI is better for detection

III - Cerebral Edema

Generally resolves within 2 weeks

- loss of grey/white matter interface- compressed ventricles- effacement of the sulci

IV - Herniation

I - Midline Shift & Subfalcine Herniation

Subfalcine herniation is herniation of Cingular gyrus underneath the falx cerebri.

Presence of midline shift usuallysignify Subfalcine herniation, and viceversa.

II - Transtentorial herniationCentral herniation is defined as both temporal lobes descend through the tentorial incisura

Effacement of the cistern around the midbrain

III - Tonsillar Herniation

- obliteration of CSF space- displaced portions of cervicomedullary junction

CT scan in spine trauma

I - Compression fracture

II – Burst fracture

III – Flexion fracture

III – fracture dislocation

The end

Thank you