بسم الله الرحمن الرحيم

1. بسم الله الرحمن الرحيم

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

4. Interpretation • 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 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 thenormal appearance is not known!!

12. 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. 1995-1999 • White matter brighter than Gray

15. T2Characteristics • 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. 1995-1999 • 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. 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. RIGHT LEFT Frontal lobe Midbrain Cerebellum What to look for? In CT HeadBrain tissue (windows)Pre contrast Post contrastBone detail (window) Brain tissue Bone detail Pre contrast Post contrast

24. RIGHT LEFT Frontal lobe Midbrain Cerebellum 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 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. Subdural Hematoma Epidural 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. RIGHT LEFT Frontal lobe Midbrain Cerebellum BIDMC PACS system

30. RIGHT LEFT Frontal lobe Midbrain Cerebellum BIDMC PACS system Patient’s B Head CT (no contrast) 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. RIGHT LEFT Frontal lobe Midbrain Cerebellum

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 http://www.strokecenter.org/education/ais_vessels/ais048.html

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. RIGHT LEFT ACA MCA PCA internal carotid internal carotid vertebral arteries MRA - Circle of Willis Our Patient Anatomic Diagram b a s i l a r http://www.strokecenter.org/education/ais_vessels/ais048.html 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. GROOVE FOR MCA CORONAL SUTURE SELLA TURCICA 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. NORMAL WATERS VIEW Medial/Inferior orbital wall blow-out Orbital Fracturesblow-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 seenhere)

49. Interpretation Non-trauma

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