This document outlines an approach for non-radiologists to interpreting CT head scans. It begins with introducing the importance of having a systematic approach similar to clinical exams. The suggested approach examines axial images of the cerebral hemispheres, ventricles, and sulci, as well as sagittal images of the corpus callosum, pituitary gland, cerebellum, brainstem, and spinal cord. Bone windows are also important for examining the base of skull and calvarium. Several case examples are then presented to demonstrate different pathologies including infarcts, traumatic brain injuries, aneurysms, subdural hematomas, metastases, and cerebral abscesses.

1. APPROACH TO CT HEAD
Gerrie Potgieter
Radiologist - I-MED
Associate lecturer - University of Notre Dame

2. INTRODUCTION
• As in clinical medicine (inspection, palpation,
percussion, auscultation) it is important to have a
systematic approach to any imaging.
• Today we will review a suggested approach to a
CT Head.
• This is my proposed system for non-radiology
clinicians.

3. INTRODUCTION
• All doctors should have a basic approach to interpreting a
CT Head.
• I am very certain that every person sitting here today will
have to review an urgent CT Head at some stage in their
career, due to a report not being available due to a technical
issue.
• We will review some basic anatomy and a suggested
approach.
• I am going to show some images and then discuss the
cases.

4. APPROACH TO CT BRAIN
Axial images:
• Cerebral hemispheres
• Ventricles (in this case
the lateral ventricles)
• Sulci (the small CSF
spaces over the surface
of the brain)

5. APPROACH TO CT HEAD
Axial images:
• Third ventricle (located
inferomedial to the
lateral ventricles)

6. APPROACH TO CT HEAD
Sagittal images:
• Corpus callosum (great
band of deeply situated
transverse white fibres
uniting the two the
cerebral hemispheres)
• Pituitary gland
• Cerebellum
• Brainstem,
• Visualised spinal
cord/cervical spine

7. APPROACH TO CT HEAD
Bone windows
• Base of skull Calvarium

8. CASE 1
• 65 year old male with sudden onset
right sided weakness.

9. LEFT MCA INFARCT
• There is loss of
grey-white
differentiation
in the left MCA
territory, subtle
oedema with
effacement of
the sulci in
keeping with
infarction.
• No evidence of
haemorrhagic
transformation.

10. Hyperdense MCA
sign, which is due to
thrombus.

11. CASE 2
• 47 year old male in high speed
motorcycle accident with severe head
injuries.
• GCS 7

12. TRAUMATIC BRAIN INJURY
Case courtesy
of Dr Derek
Smith,
Radiopaedia.
org, rID:
36667
Superficial
subarachnoid/extra
-axial haematoma
Intraparenchymal
haematoma with
surrounding
oedema/contusion
Scalp haematoma
Mild
midline shift
towards the
left

13. TRAUMATIC BRAIN INJURY
Case courtesy
of Dr Derek
Smth,
Radiopaedia.
org, rID:
36667
• The haematomas, contusions and other findings we see is the tip of the
iceberg.
• What is more important is the severe diffuse axonal injury (DAI).

14. DIFFUSE AXONAL INJURY
• DAI is the result of shearing forces, typically from rotational acceleration
or a deceleration.
• Due to the slightly different specific densities of white and grey matter,
shearing due to change in velocity has a predilection for axons at the
grey-white matter junction.
• It is important to know that these patients present with a low GCS in the
context of a severe head trauma and these CT Heads may look relatively
normal, with small haemorrhages only.

15. CASE 3
• 27 year old male
• Sudden onset severe headache in gym.

16. • High density/ acute
Intraventricular
haemorrhage
Subarachnoid haemorrhage

17. Subarachnoid
haemorrhage
Dilated temporal
horns, in keeping
with early
hydrocephalus.

18. Small
saccular/berry
aneurysm

19. Small
saccular/berry
aneurysm

20. CASE 4
• 28 year old boxer
• 4 week history of headaches.

21. BILATERAL SUBDURAL HAEMATOMAS
The change in
density is due to
the layering effect
from the blood
products.
The lateral
ventricles show
near complete
effacement.

22. CASE 5
• 71 year old male.
• 50 pack year smoking history.
• Presents with headaches and personality
changes.

23. METASTASIS
Case courtesy of Dr
David Cuete,
Radiopaedia.org,
rID: 22895
Right frontal
cortically based
enhancing lesion,
with surrounding
low density, in
keeping with a
metastasis.

24. CEREBRAL ABSCESS
Case courtesy of
A.Prof Frank Gaillard,
Radiopaedia.org, rID:
19468
Right posterior frontal rim
enhancing lesion
This is different from a metastasis
in that rim enhancement is usually
only seen in established infection.
In cerebral infection we usually get
four stages:
• early cerebritis
• late cerebritis
• early abscess/encapsulation - may
occur 10 days after infection
• late abscess/encapsulation - may
occur more than 14 days after
infection

25. IN SUMMARY
Axial images:
• Cerebral hemispheres
• Ventricles (in this case the lateral
ventricles)
• Sulci (the small CSF spaces over the
surface of the brain)
Sagittal images:
• Corpus callosum (great band of
deeply situated transverse white
fibres uniting the two the cerebral
hemispheres)
• Pituitary gland
• Cerebellum
• Brainstem,
• Visualised spinal cord/cervical spine
Bone windows
• Base of skull
• Calvarium

26. THANK YOU
References:
• Radiopaedia
• UpToDate