0
By DR A K SINGH
LECTURER
PG DEPT OF MEDICINE
BASICS OF
NEUROIMAGING
What We Need to Know
• Air is very black (less than -300 HU)
• Water/CSF is black (near 0 HU)
• Bone is very dense/white (...
Normal CT of brain
• Ventricles are normal sized,
the grey versus white distinction
is clear.
• Midline is straight.
• Sul...
Systemic Approach to Head CT
Interpretation
• Symmetry – Compare left and right side of the cranium
• Midline – Look for m...
Lateral View of Brain
Cross-sectional Anatomy
• Grey/White interface, Subcortical white
matter
Cross-sectional Anatomy
• Paired of crescent-shape = Twin bananas
Cross-sectional Anatomy
Basal ganglia
Cross-sectional Anatomy
• Third ventricle, Basal ganglia, Superior
cerebellar cistern
Physiologic Calcification
Cross-sectional Anatomy
• Third ventricle, Smiley face
Cross-sectional Anatomy
• Midbrain, Interpeduncular cistern
Cross-sectional Anatomy
• Star shape ~ Circle of Willis,
• Fourth ventricle, Temporal horn ~ slit
Cross-sectional Anatomy
• Base of skull, Midline bony prominence,
• Prepontine cistern, Pretrous bone, Frontal
Cross-sectional Anatomy
• Orbits, Ethmoid air cell
GREEN IS
TEMPORAL
LOBE
RED
DENOTES
FRONTAL
LOBE
GREEN
DENOTES
TEMPORAL
LOBE
RED
DENOTES
FRONTAL
LOBE
GREEN-
TEMPORAL
LOBE
RED-
FRONTAL
LOBE
GREEN-
TEMPORAL
LOBE
RED-
FRONTAL
LOBE
GREEN-
TEMPORAL
LOBE
YELLOW-
OCCIPITAL
LOBE
RED-
FRONTAL
LOBE
GREEN-
TEMPORAL
LOBE
YELLOW-
OCCIPITAL
LOBE
RED-
FRONTAL
LOBE
GREEN-
TEMPORAL
LOBE
YELLOW-
OCCIPITAL
LOBE
RED –FRONTAL
LOBE
BLUE-PARIETAL
LOBE
GREEN-
TEMPORAL
LOBE
YELLOW-
OCCIPITAL
LOBE
RED-
FRONTAL
LOBE
BLUE-
PARIETAL
LOBE
YELLOW-
OCCIPITAL
LOBE
RED –
FRONTAL
LOBE
BLUE-
PARIETAL
LOBE
YELLOW-
OCCIPITAL
LOBE
RED –
FRONTAL
LOBE
BLUE-
PARIETAL
LOBE
YELLOW-
OCCIPITAL
LOBE
FRONTAL
LOBE –RED
PARIETAL
LOBE - BLUE
RED –
FRONTAL
LOBE
BLUE-
TEMPORAL
LOBE
RED –
FRONTAL
LOBE
BLUE –
TEMPORAL
LOBE
Thalmus
Aqueduct of sylviusS
Cerebellum
Fourth
ventricle
Corpus
callosum
Midbrain
Pons
Medulla
Corpus callosum Thalamus Aq...
MRI
• Based on the absorption and emission of radiofrequency
energy – so there is NO ionizing radiation.
• Uses magnets rangin...
• The time it takes the protons to regain their equilibrium state =
• RELAXATION TIME.
„
• 2 types of relaxation time: T1 ...
Short TR + Short TE = T1 weighted
•Dark
– CSF
– Increased Water –
edema,
– tumor, infarct,
inflammation,
– infection, hemo...
Long TR + Long TE= T2 weighted
• Dark
– Low Proton Density,
– calcification, fibrous
tissue
– Paramagnetic
substances -
• ...
Fluid-Attenuated Inversion Recovery
FLAIR
• Basically T2 without CSF brightness
• TE>80 and TR>10,000
• Edema and Gliosis ...
T1W / T2W / FLAIR
T1W T2W FLAIR
Fig. 1.1 Post Contrast Axial
MR Image of the brain
1
2
3
4
5
Post Contrast sagittal
T1 Weighted M.R.I.
Section at the leve...
Fig. 1.2 Post Contrast Axial
MR Image of the brain
7
6
Post Contrast sagittal
T1 Wtd M.R.I.
Section at the level of
medull...
Fig. 1.3 Post Contrast Axial
MR Image of the brain
15
8
9
10
11
12
13
14
16
17
Post Contrast sagittal
T1 Wtd M.R.I.
Sectio...
Fig. 1.4 Post Contrast Axial
MR Image of the brain
18
19
20
21
22
Post Contrast sagittal T1
Wtd M.R.I.
Section at the leve...
Fig. 1.5 Post Contrast Axial
MR Image of the brain
23
24
25
26
27
Post Contrast sagital T1 Wtd
M.R.I.
Section at the level...
Fig. 1.6 Post Contrast Axial
MR Image of the brain
28
29
30
31
32
38
33
34
36
35
37
Post Contrast sagittal
T1 Wtd M.R.I.
S...
Fig. 1.7 Post Contrast Axial
MR Image of the brain
39
40
41
Post Contrast sagittal
T1 Wtd M.R.I.
Section at the level of
C...
Fig. 1.8 Post Contrast Axial
MR Image of the brain
42
43
44
Post Contrast sagittal
T1 Wtd M.R.I.
Section at the level of
B...
T1W T2W FLAIR
acute/subacute hemorrhage
acu
te
SUBACUTE T2WI T1WI
Strokes show up faster on MRI
than CT
MRI and CAT views of the same
whole R. hemispherical infarct
Some very big strokes settle down and don’t require surgical
...
MR:44396
MRI appearances of acute
cerebral infarction
T2WI T1WI Flair
The End…
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Basics of ct mri

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BASICS OF CT AND MRI

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Transcript of "Basics of ct mri"

  1. 1. By DR A K SINGH LECTURER PG DEPT OF MEDICINE BASICS OF NEUROIMAGING
  2. 2. What We Need to Know • Air is very black (less than -300 HU) • Water/CSF is black (near 0 HU) • Bone is very dense/white (500-3000 HU) • Blood is white (60-80 HU) • Brain is gray 35-50 HU
  3. 3. Normal CT of brain • Ventricles are normal sized, the grey versus white distinction is clear. • Midline is straight. • Sulci are symmetrical on bothsides. • Skull is intact with no scalp edema.
  4. 4. Systemic Approach to Head CT Interpretation • Symmetry – Compare left and right side of the cranium • Midline – Look for midline shift • Cross-sectional anatomy – Review anatomical landmark for each slide – Brain tissue : gray matter, white matter , intracerebral lesions – CSF space : ventricle, basal cistern, cortical sulci, fissure – Skull and soft tissue : scalp swelling, fractures, sinuses, orbit • Subdural windows : Look for blood collection adjacent to the skull • Bone windows : Skull, orbit and sinuses, intracranial air
  5. 5. Lateral View of Brain
  6. 6. Cross-sectional Anatomy • Grey/White interface, Subcortical white matter
  7. 7. Cross-sectional Anatomy • Paired of crescent-shape = Twin bananas
  8. 8. Cross-sectional Anatomy
  9. 9. Basal ganglia
  10. 10. Cross-sectional Anatomy • Third ventricle, Basal ganglia, Superior cerebellar cistern
  11. 11. Physiologic Calcification
  12. 12. Cross-sectional Anatomy • Third ventricle, Smiley face
  13. 13. Cross-sectional Anatomy • Midbrain, Interpeduncular cistern
  14. 14. Cross-sectional Anatomy • Star shape ~ Circle of Willis, • Fourth ventricle, Temporal horn ~ slit
  15. 15. Cross-sectional Anatomy • Base of skull, Midline bony prominence, • Prepontine cistern, Pretrous bone, Frontal
  16. 16. Cross-sectional Anatomy • Orbits, Ethmoid air cell
  17. 17. GREEN IS TEMPORAL LOBE
  18. 18. RED DENOTES FRONTAL LOBE GREEN DENOTES TEMPORAL LOBE
  19. 19. RED DENOTES FRONTAL LOBE GREEN- TEMPORAL LOBE
  20. 20. RED- FRONTAL LOBE GREEN- TEMPORAL LOBE
  21. 21. RED- FRONTAL LOBE GREEN- TEMPORAL LOBE YELLOW- OCCIPITAL LOBE
  22. 22. RED- FRONTAL LOBE GREEN- TEMPORAL LOBE YELLOW- OCCIPITAL LOBE
  23. 23. RED- FRONTAL LOBE GREEN- TEMPORAL LOBE YELLOW- OCCIPITAL LOBE
  24. 24. RED –FRONTAL LOBE BLUE-PARIETAL LOBE GREEN- TEMPORAL LOBE YELLOW- OCCIPITAL LOBE
  25. 25. RED- FRONTAL LOBE BLUE- PARIETAL LOBE YELLOW- OCCIPITAL LOBE
  26. 26. RED – FRONTAL LOBE BLUE- PARIETAL LOBE YELLOW- OCCIPITAL LOBE
  27. 27. RED – FRONTAL LOBE BLUE- PARIETAL LOBE YELLOW- OCCIPITAL LOBE
  28. 28. FRONTAL LOBE –RED PARIETAL LOBE - BLUE
  29. 29. RED – FRONTAL LOBE BLUE- TEMPORAL LOBE
  30. 30. RED – FRONTAL LOBE BLUE – TEMPORAL LOBE
  31. 31. Thalmus Aqueduct of sylviusS Cerebellum Fourth ventricle Corpus callosum Midbrain Pons Medulla Corpus callosum Thalamus Aqueduct of Sylvius Fourth Ven. Mid-brain Pons Cerebellum Medulla oblongata SECTION AT MID-SAGITTAL PLANE
  32. 32. MRI
  33. 33. • Based on the absorption and emission of radiofrequency energy – so there is NO ionizing radiation. • Uses magnets ranging in strength from 0.3 to 1.5 Tesla to create a magnetic field around the patient. • Magnetic field causes protons in the body to align and then pulsed radiowaves are directed at the patient causing a disturbance of the proton alignment. • Atoms then realign and in doing so, emit the absorbed radiofrequency
  34. 34. • The time it takes the protons to regain their equilibrium state = • RELAXATION TIME. „ • 2 types of relaxation time: T1 – Longitudinal (parallel to the magnetic field) and T2 –transverse (perpendicular to the mag field). „ • Relaxation Time and Proton Density are the main determinants of signal strength. „ • The main determinants of contrast or the weighting are: ‹ 1)Repetition Time (TR) – the time between successive RF pulses 2)Echo Time (TE) – time between the arrival of the RF pulse that excites and the arrival of the return signal at the detector.
  35. 35. Short TR + Short TE = T1 weighted •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
  36. 36. Long TR + Long TE= T2 weighted • Dark – Low Proton Density, – calcification, fibrous tissue – Paramagnetic substances - • deoxyhemoglobin, • methemoglobin (intracellular), • iron, hemosiderin, melanin – Protein-rich fluid – Flow Void • Bright – CSF – Increased Water – edema, – tumor, infarct, inflammation, – infection, subdural collection – Methemoglobin – (extracellular) in subacute – hemorrhage
  37. 37. Fluid-Attenuated Inversion Recovery FLAIR • Basically T2 without CSF brightness • TE>80 and TR>10,000 • Edema and Gliosis are hyperintense
  38. 38. T1W / T2W / FLAIR
  39. 39. T1W T2W FLAIR
  40. 40. Fig. 1.1 Post Contrast Axial MR Image of the brain 1 2 3 4 5 Post Contrast sagittal T1 Weighted M.R.I. Section at the level of Foramen MagnumAnswers 1. Cisterna Magna 2. Cervical Cord 3. Nasopharynx 4. Mandible 5. Maxillary Sinus
  41. 41. Fig. 1.2 Post Contrast Axial MR Image of the brain 7 6 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of medulla Answers 6. Medulla 7. Sigmoid Sinus
  42. 42. Fig. 1.3 Post Contrast Axial MR Image of the brain 15 8 9 10 11 12 13 14 16 17 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of PonsAnswers 8. Cerebellar Hemisphere 9. Vermis 10. IV Ventricle 11. Pons 12. Basilar Artery 13. Internal Carotid Artery 14. Cavernous Sinus 15. Middle Cerebellar Peduncle 16. Internal Auditory Canal 17. Temporal Lobe
  43. 43. Fig. 1.4 Post Contrast Axial MR Image of the brain 18 19 20 21 22 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Mid Brain Answers 18. Aqueduct of Sylvius 19. Midbrain 20. Orbits 21. Posterior Cerebral Artery 22. Middle Cerebral Artery
  44. 44. Fig. 1.5 Post Contrast Axial MR Image of the brain 23 24 25 26 27 Post Contrast sagital T1 Wtd M.R.I. Section at the level of the III Ventricle Answers 23. Occipital Lobe 24. III Ventricle 25. Frontal Lobe 26. Temporal Lobe 27. Sylvian Fissure
  45. 45. Fig. 1.6 Post Contrast Axial MR Image of the brain 28 29 30 31 32 38 33 34 36 35 37 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Thalamus Answers 28. Superior Sagittal Sinus 29. Occipital Lobe 30. Choroid Plexus within the occipital horn 31. Internal Cerebral Vein 32. Frontal Horn 33. Thalamus 34. Temporal Lobe 35. Internal Capsule 36. Putamen 37. Caudate Nucleus 38. Frontal Lobe
  46. 46. Fig. 1.7 Post Contrast Axial MR Image of the brain 39 40 41 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Corpus Callosum Answers 39. Splenium of corpus callosum 40. Choroid plexus within the body of lateral ventricle 41. Genu of corpus callosum
  47. 47. Fig. 1.8 Post Contrast Axial MR Image of the brain 42 43 44 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Body of Corpus Callosum Answers 42. Parietal Lobe 43. Body of the Corpus Callosum 44. Frontal Lobe
  48. 48. T1W T2W FLAIR
  49. 49. acute/subacute hemorrhage acu te SUBACUTE T2WI T1WI
  50. 50. Strokes show up faster on MRI than CT
  51. 51. MRI and CAT views of the same whole R. hemispherical infarct Some very big strokes settle down and don’t require surgical decompression. This man opens his eyes to verbal on nasal cannula and follows on the right side 10 days post stroke.
  52. 52. MR:44396 MRI appearances of acute cerebral infarction T2WI T1WI Flair
  53. 53. The End…
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