1. بسم الله الرحمن الرحيم

2. Interpretation in·ter·pre·ta·tion DR.Tajuddin Malabarey
Associate professor
365-March 2011

4. Interpretation Clarification, Explanation, Illumination, Illustration.
Something that serves to explain or clarify:
Clarification,
Explanation,
Illumination,
Illustration.
The act or process of explaining the meaning of something.

5. Interpretation

6. Interpretation 3= How to interpret the abnormality?
1=Normal Radiological Anatomy
2= How to look at the images?
(a) Where to look?
Systematic approach
(b) what look for:
(i) abnomal opacty
(ii) abnorma radiolucency
(iii) distotion or displacement of a normal structure
3= How to interpret the abnormality?
(a) Recognizing the abnormality,
(b) Describing it in generic terms,
(C) Giving a specific diagnosis

7. Normal Radiological Anatomy
Normal radiological image of certain age and sex is a mental image that must be developed

8. How to build up a normal mental image
By developing a systematic approch to examine the radiological image
Advantages:
Minimizes the chance of missing an abnormality
Makes complex images easier to read with practice
Builds up a mental databank of what is normal

9. Normal VS, Abnormal
It is not possible to call an image abnormal if the normal appearance is not known!!

12. On non-contrast head CT:
In order to recognize the abnormal, you first need to know the appearance of the normal.
On non-contrast head CT:
Bone is white
Calcium is white;
Acute hemorrhage is usually white
Brain parenchyma is light grey;
White matter is darker than grey matter
CSF is very dark grey;
Sulci, cisterns and ventricles
Air is black;
Nasal cavity, sinuses, mastoid air cells
White
Light Grey
Charcoal
Grey
Black

14. T1 Characteristics Dark CSF
Increased Water – edema, tumor, infarct, inflammation, infection, hemorrhage (hyperacute or chronic)
Low proton density, calcification
Flow Void
Bright
Fat
Subacute hemorrhage
Melanin
Protein-rich Fluid
Slowly flowing blood
Gadolinium
Laminar necrosis of an infarct
Johnson,KA and Becker, JA. The Whole Brain Atlas
White matter brighter than Gray

15. T2 Characteristics Dark
Low Proton Density, calcification, fibrous tissue
Paramagnetic substances - deoxyhemoglobin, methemoglobin (intracellular), iron, hemosiderin, melanin
Protein-rich fluid
Flow Void
Bright
Increased Water – edema, tumor, infarct, inflammation, infection, subdural collection
Methemoglobin (extracellular) in subacute hemorrhage
Johnson,KA and Becker, JA. The Whole Brain Atlas
Gray matter brighter than white

16. Interpretation Learn Normal Radiological Anatomy
How to look at the images?
How to interpret the abnormality?

17. How to look at the images?
Where to look?
Systematic approach
What to look for?
The documentary evidence of name and age
Technical factors
Areas of interest (Normal anatomical structures)

18. Patient Name

19. 3.Areas of interest (Normal anatomical structures)
What to look for?
3.Areas of interest (Normal anatomical structures)

20. Systematic Approach to reading a Head CT
I. Check Brain Parenchyma
Check grey/white differentiation
Gyri
Look for blood
Surgeons need to know (size of hematoma, extent of midline shift, herniation)
II. Check CSF spaces: Ventricles, Cisterns and Sulci
CSF spaces (ventricles and cisterns)
size, symmetry, midline shift
herniation
Subfalcine – cingulate gyrus crosses falx
Transtentorial – temporal lobe into tentorial notch
Cerebellar – cerebellum into foramen magnum

21. Systematic Approach to reading a Head CT (cont’d 2)
III. Check face and skull bones on bone windows
Do not confuse sutures with fracture especially in pediatric patients
IV. Check “air spaces”
Sinuses
Nasal airway
Ear Canals and Mastoid air cells

23. What to look for? In CT Head Brain tissue (windows) Pre contrast Post contrast Bone detail (window)
Frontal lobe
Midbrain
Cerebellum
RIGHT
LEFT
Bone detail
Pre contrast Post contrast

24. what look for: (i) abnomal opacty (ii) abnorma radiolucency (iii) distotion or displacement of a normal structure
Normal
distotion or displacement of a normal structure
abnorma radiolucency
Frontal lobe
Midbrain
Cerebellum
RIGHT
LEFT
abnomal opacty

25. 3= How to interpret the abnormality?
(a) Recognizing the abnormality,
(b) Describing it in generic terms,
(C) Giving a specific diagnosis

26. Patient’s A Head CT Film findings:
R frontoparietal subdural hematoma (6 mm)
Midline marker
R temperoparietal epidural hematoma (1.8 cm)
6 mm leftward shift of lateral ventricles
Right lateral ventricle
Left lateral ventricle
Effacement of R sulci
BIDMC

27. Epidural Subdural Hematoma Parenchymal Hemorrhage
Subarachnoid Hemorrhage
Parenchymal Hemorrhage

28. Patient B 57yr old woman History of migraines
Presents with persistent headache
several months duration
different from her usual headache
Need to rule out intracranial abnormality

29. BIDMC PACS system
Frontal lobe
Midbrain
Cerebellum
RIGHT
LEFT

30. Patient’s B Head CT (no contrast)
BIDMC PACS system
Frontal lobe
Midbrain
Cerebellum
RIGHT
LEFT
Film Findings:
Spherical mass
Smooth margined
High attenuation
Slight mass effect
Located just anterior to the Circle of Willis
No acute hemorrhage, edema, infarct

31. Frontal lobe
Midbrain
Cerebellum
RIGHT
LEFT

32. DDx: Cerebral mass Tumor Hematoma Abscess
Arterio-venous malformation (AVM)
Aneurysm

33. Patient’s B Head CT (with contrast)
RIGHT
LEFT
Frontal lobe
RIGHT
LEFT
Frontal lobe
cerebellum
cerebellum
BIDMC PACS system
2 brightly enhancing round lesions suggestive of cerebral aneurysms
BIDMC PACS system

34. Lets review the anatomy of the Circle of Willis
Communicating system of vessels that supplies blood to the brain
Anterior portion fed by the internal carotid arteries
Posterior portion fed by the vertebral arteries

35. Patients B Axial MR (T2 sequence)
T2 sequence: CSF is bright (“high signal”)
RIGHT
LEFT
RIGHT
LEFT
BIDMC PACS system
BIDMC PACS system
Round lesions with flow void confirmed

36. Menu of tests for evaluating suspected: Cerebral aneurysm
Computed tomography (CT) + contrast
Magnetic resonance imaging (MRI)
Magnetic resonance angiograpy (MRA)
Cerebral angiography

37. MRA - Circle of Willis Our Patient Anatomic Diagram
vertebral
arteries
internal
carotid
ACA
MCA
PCA
RIGHT
LEFT b a s i l a r
Internal carotid artery
aneurysms
BIDMC PACS system

38. Patient C

39. Patient’s C
Normal

40. Patient’s C
Normal

41. Patient’s C

42. Interpretation
Features of several diseases,
trauma
and non-trauma

43. CNS Trauma Imaging

44. Normal Linear fracture Epidural H Depressed fracture CORONAL SUTURE
SELLA TURCICA
CORONAL SUTURE
GROOVE FOR MCA
EXT.AUD MEATUS
ORBITAL GROOVE
Normal
Linear fracture
Epidural H
Depressed fracture

46. Orbital Fracturesblow-out
NORMAL WATERS VIEW
Medial/Inferior orbital wall blow-out

47. Orbital Fracturesblow-out
NORMAL WATERS VIEW
Medial/Inferior orbital wall blow-out
Axial CT
Coronal CT

48. Orbital Fracturesblow-out
Medial/Inferior orbital wall blow-out
Depressed right orbital floor
Opacification of right maxillary sinus
Opacification of right ethmoid sinus
“Hanging tear drop”: herniation of orbital fat into maxillary sinus (not seen here)

49. Interpretation
Non-trauma

50. Extra-axial vs Intra-axial
(external to pia)
(beneath pia)
Meningioma Glioma

51. Supra-tentorial vs Infra-tentorial
Glioma Medulloblastoma

52. Nonenhanced computed tomography scan shows a hyperdense mass resulted in midline shift to the right aspect in the left frontal lobe
DSA, Left external carotid artery injection shows early stain of the mass
CECT shows a homogeneous enhancing mass located in the left frontal lobe.
DSA: Left external carotid artery shows delayed stain of the mass

53. Hydrocephalus versus Cerebral Atrophy
Definition
:Hydrocephalus is abnormal accumulation of intracranial fluid resulting from structural or functional block to normal flow of CSF,
cerebral atrophy is parenchymal volume loss

55. Hydrocephalus is abnormal accumulation of intracranial fluid resulting from structural or functional block to normal flow of CSF,

56. cerebral atrophy is parenchymal volume loss

57. Agenesis of the corpus callosum

58. Patterns of edema Edema: Increase in tissue water
CT - decreased density
MR - T1W - decreased signal
MR - T2W - increased signal

59. Patterns of edema Vasogenic Cytogenic white matter only
(intertitial)
white matter only
neoplasm
abscess
Cytogenic
(intracellular)
both gray and white matter
infarction
Normal
White&gray matter
Vaogenic oedema (tumor &inflamation) Cytotoxic oedema ( infarction)
White matter

64. CONCLUSION (b) Describing it in generic terms,
KNOW YOUR Normal Radiological Anatomy
look for:
(i) abnormal opacity
(ii) abnormal radiolucency
(iii) distortion or displacement of a normal structure
Interpret the abnormality:
(a) Recognizing the abnormality,
(b) Describing it in generic terms,
(C) Giving a differential diagnosis
Give a specific diagnosis
KNOW your radiological terminology

65. BEST LUCK
HOPE THIS WAS HELPFUL