DR Mohammad Aburumman Arab Board OF RADIOLOGY

-Fellow of I.R

BRAIN CT SCAN PART I

REVIEW FOR ANATOMY AND Common acute conditions

for clinician

SCHEME OF THE LECTURE

BASIC PRINCIPLES OF CT SCAN

NORMAL ANATOMY AS SEEN ON CRANIUM CT SCANS

ILLUSTRATIONS

Basics: • X-RAYS ARE ABSORBED DIFFERENTLY BY DIFFERENT TISSUES

• Always describe CT findings as densities- isodense/hypodense/hyperdense.

• Higher density = the appearance IS WHITER • Lower density = the appearance IS DARKER• Brain is the reference density• Anything of the density as brain= isodense• Higher density than brain= hyperdense ( BONE is example)• Anything darker than brain= hypodense( ie. CSF and air )

HOUNSFIELD UNITS

H.U! ?

Represent the density of tissue

Calculated automatically by Ct scan machine processor by Place the marker on area of interest

8

30 H.U

45 H.U

1000H.U

Petroclinoid lig. calcification

 tentorium cerebelli

FALX CEREBELLI

FALX CEREBELLI

STROKE

I schaemic Stroke 1 st 6 Hours :60% Normal Vogue subtle Hypodensity .Sulcal effacment Loss of Grey/White matter

Distinction ...12-24 More prominant low

attenuated area .

Ischaemic Stroke After 24 hours Well demarcated low attenuation . 3-5 days Mass effect which may gone by 2-4

weeks . Long Term Encephalomalcia

IS CONTRAST NECESSARY??

Hemorrhagic Stroke

Sub Dural and Epidural Hematoma Usually traumatic >>> Subdural Venous bleed due to stretching and tearing of

bridging cortica

Epidural Arterial bleed The source of bleeding is usually a torn

meningeal artery (most commonly, the middle meningeal artery)

meningeal artery. Skull Fracture . >95% are supratentorial temporoparietal: 60%

EDH

S.A.H

TO

BE

CONTINUE

THANK YOU