basics of MRI image interpretation. For freshers in MRI.

2. Contents of this talk
 Introduction.
 MRI of brain.
 MRI of spine.
 Others.
My aim is to focus on common
and significant findings.

3. Tiny motion of protons in a
magnetic field is
responsible for MR images.
Difficult to believe but
true !

4. How does MRI (Magnetic Resonance
Imaging) work..?
 Design of MRI Magnet

5. Inventors of MRI
Peter Paul Raymond
Mansfield Lautebur Damadian
Nobel prize for physiology or
medicine 2003

6. What`s so special about MRI..
 Its unique multiecho
technique gives tremendous
insight to living body in
health and disease.

7. What is T1 sequence..
T1 image of brain
 T1 refers to time taken for
return of net magnetization.
 A T1 weighted image is
produced by this property.
 Practically , we need to
identify T1 weighted image.
 Remember FLUID IS BLACK
on T1.

8. What is T2 sequence..
T2 image of brain
 T2 refers to loss of transverse
magnetization.
 A T2 weighted image is
produced by using this
property.
 Practically we need to know
FLUID IS BRIGHT on T2
More than 100 different
sequences are there FLAIR
,STIR,CISS,SPACE,GRE,SSSFE ,
FSE,TSE………..

10.  Brain MRI is the gold standard in detecting
intracranial lesions.
 It approaches histopathology , can predict functional
outcome of treatment, assess brain vessels.
 It does have few limitations

11. What we will do..
 Anatomy/ Identifying lobes.
 Few case examples.

17.  Case 1.
 39 year old male with
headache and left frontal
seizures.
 CT brain shows edema
right frontal lobe.

18. T2 hypointensity with edema in right
frontal lobe.

19. T1 mild hypointensity in right frontal
lobe.

20. Conglomerate ring enhancing
lesions. Consistent with
tuberculoma.

21. Is MRI pathognomonic in diagnosis of tuberculoma..?
 No.
 Ring enhancing lesion with T2 hypointensity in
appropriate clinical situation suggests tuberculoma.
 Lesion needs follow up.
 Presence of caseation is responsible for T2
hypointensity.

22. Case 2
 Headache in 28 year old
female
 Papilloedema present
 CT -? Filling defect in
venous sinuses.

23. Lack of visualization of superior sagittal sinus and
left lateral sinus. Suggestive of thrombus.

24. Brain images show mild edema in right frontal
lobe.

25.  MRI with venogram
is the modality of
choice in assessing
venous sinus
thrombus and its
complications.
Normal MR venogram.

26.  Case 3.
 21 year old lady with
previous history of
vision loss. Now
complains of numbness
of lower limbs.

27. Sagittal T2 shows periventricular
hyperintensities.

28. Axial T1 POST
Coronal FLAIR Axial T2
CONTRAST

29. Diagnosis- multiple sclerosis.
 Though lesions are
characteristic of multiple
sclerosis , temporal clinical
course is necessary to
confirm clinical diagnosis.
 Enhancement detects acute
plaques.

30. Case 4
 5 month old infant with growth retardation and
recurrent seizures.
 Sibling had similar history and died due to unknown
illness.

31. T2 hyperintensity seen in basal
ganglia.

32. No abnormality in FLAIR or T1
sequence

33. Diffusion imaging
shows areas of
recent ischemia /
infarct well.
It also has other
applications.
Diffusion imaging shows areas of
diffusion restriction.

34. Diagnosis– Mitochondrial cytopathy /
Leigh`s disease
 Bilateral symmetrical areas of abnormal signal in an
infant with diffusion restriction in an infant is
suggestive of mitochondrial disease.
 Findings need to be confirmed with serum lactate
estimation.

36. Spine imaging…
 MRI is widely used to image
spine.
 It has become first line
investigation in spine
imaging.
 Key in spine MRI is to pick
up the significant and
discard insignificant.

37. conus
Nerve
root
Paramedian Midsagittal
section section
Lateral section

38. Axial section at L4-L5 disc Axial section at vertebral body
level , shows L4 root exiting out level , shows pedicles , nerve
of neural foramen , L5 root at roots in cauda equina
lateral recess

39. • Lateral recess is the space bordered anteriorly by posterior vertebral
body , posteriorly by superior articular facet , laterally by pedicle. In
lumbar spine , nerve root is usually trapped by herniated disc here.

40. Disc bulge
Disc protrusion , note broad
base
Migrated , extruded disc.

41. Right paracentral disc extrusion with
lateral recess stenosis and S1 root
compression

42. Why is this classification
important..?
 52% of adult population have disc bulges.
 27% have disc protrusions.
 1% have extrusions and are invaribly symptomatic.
N Eng J Med 1994: 331

43. Degenerative
fatty endplate
change.
Look for fat ,
paravertebral
swelling to
differentiate from
infection.

44. Tuberculosis of DL spine causing low back
ache
Check list for infection
2.Disc involvement.
3.Contiguous vertebrae.
4.Pre and para vertebral
fluid collection/abscess

45. Intradural extramedullary tumor , possibly
neurofibroma.

46. Old fracture
at D12
vertebral
level.
Presence of fat
signal is helpful in
differentiating fat
from edema
signal.

48. Case 5
 63 year old lady with sudden onset of renal function
deterioration. Pulses not felt in lower limbs.
 Color doppler -- ? Renal artery embolus.

49. Aortic occlusion , left renal artery also
occluded.

50. Patient was
thrombolysed.
Follow up MRI
after 1 week
shows good
improvement

51. Case 6
 Middle aged male with history of right side sensory
symptoms. CT showing right thalamic lesion, ?infarct/
SOL

52. Normal
Glioma
spectrum.
MR Spectroscopy
This graph is called spectroscopy , a sort of chemical
assessment of brain lesions.
showing normal
metabolites

53. spectroscopy
 As different lesions have different chemical
composition , spectroscopy gives different graphs to
different lesions.
 Though not 100% accuracy , is a good tool in assessing
brain lesions.
 This case was a high grade glioma.

54. Normal spectrum
Tuberculoma spectrum

55. Cardiac MRI , valuable tool in assessing
viability , cardiomyopathy , pediatric
cardiology. This is a case of
cardiomyopathy.

56. MR angiography lower limbs
nearly equals conventional
angiogram.
Infrarenal aortic occlusion

57.  MR based
cholangiogram is an
ideal technique for
biliary tract assessment.
CBD
Calculi

59. Which MRI is better
open or 1.5 Tesla ..?

60. Which MRI is better
open or 1.5 Tesla ..?
Open 0.2 T
1.5 Tesla

61. I have a patient with metallic implant , can I ask for
MRI..?
 A titanium implant can be done immediately after
surgery.
 Rest of metallic implant , better wait for 6 weeks and
then proceed for MRI.
J MRI 2002

62. Is MRI safe in pregnancy…?
 No harmful effects demonstrated so far to mother and
fetus.
 However concerns remain , FDA has not declared
MRI is completely safe in pregnancy.
 Present consensus is that MRI to be done under
Definite indications for mother and fetus.

63. Why musculoskeletal system not
discussed..
 Sorry , as other systems were thought more relevant
to today`s audience..

64. Are MRI contrast gadolinium based
compounds harmful in renal failure..
 Use is safe in mild- moderate renal failure.
 It should be used with caution in patients with severe
renal failure.
 Large amounts of MR contrast when used in severe
CRF (GFR less than 30 ml/minute) is suspected to
cause a disease called NSF (nephrogenic systemic
fibrosis).
 Hence caution is indicated in these circumstances.

65. Summary ….
 MRI has made tremendous clinical impact.
 Findings need interpretation with caution and after
proper discussion.

66. Than
k you
Can you
guess the
probable
diagnosis