pediatirc neuroimaging , primer for pediatricians interested in neuroimaging and basic stuff for radiologists. included examples of normal and abnormal. when to do what imaging

1. Dr Krishna Kiran MD,DNB,FRCR
Radiologist
Calicut

2. Tools available.
What is normal.?
What to use and when..?

4. Available tools.
Xray skull
Neurosonogram
CT brain
MRI brain
PET CT
Digital subtraction angiography.

5. AP view Towne `s view
Skull radiographs

6. AP view Towne `s view
Sagittal
suture
Lambdoid
suture
Coronal suture

7. Lateral

8. Lateral
Lambdoid
suture
Coronal
suture
Skull Xrays have
few indications.
No longer used in
trauma.

9. Neurosonogram
Refers to performance of high
frequency ultrasound across
open fontanelle.
Critical in premature babies.
Used mainly for intraventricular
hemorrhage , hydrocephalus ,
HIE assessment.

10. Neurosonogram
For Against
Bedside.
Economical.
No radiation.
Equals or better than CT in
good operators
Possible only in first year.
Operator dependent.
Usually needs CT
confirmation.

11. CT brain
Employs X rays and
computer to deliver cross
sectional images of body.

12. CT brain
For Against
Established technique to
detect brain pathology.
Widely available.
Less cost.
Very good to detect
hemorrhage , fracture etc.
Radiation risk.
Not as sensitive as MRI.
Not good in assessing White
matter disease.

14. What is radiation risk..?
For a cumulative dose of 50-60 mGy (milli Gray a unit
of radiation absorbed dose) there is 3 fold increase in
brain tumors when performing brain CT , 3 fold
increase in leukemia when red marrow is exposed.

15. What is radiation risk..?
In a typical CT scanner , 2-3 head scans will give a
dose of 50-60 mGy to a child.
 Berrington de González A, Mahesh M, Kim KP, Bhargavan M, Lewis R, Mettler F, Land C.
Projected cancer risks from computed tomographic scans performed in the United States in
2007. Archives of Internal Medicine 2009; 169: 2071-7.

16. Why is radiation risk important to
children..?
Children live longer than adults , hence more time
for radiation effects to manifest. It takes 20-40 years
for cancer to manifest after exposure.
If not careful , children may get same dose as adults.
Children more sensitive to radiation.
Also increased risk of radiation induced cataract.

17. However remember that CT study can be lifesaving
many times.
Hence use judiciously.

18. MRI

19. What`s so special about MRI..
Its unique multiecho
technique gives tremendous
insight to living body in
health and disease.
Two men watching a statue in a candle. Just imagine
there were multiple candles at different angles would
not picture be clear..? This is what MRI does.

20. What is T1 sequence..
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.
T1 image of brain

21. 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………..

22. MRI BRAIN
For Against
Gold standard in detection
of pathology.
No radiation.
Images can be obtained in all
planes.
Children need sedation.
Not widely available.

24. MRI slices
through brain ,
compared to an
expert slicing
through bread
cutting uniform
pieces !.

31. Let us see some clinical
situations…

32. Case 1
9 year old with history of road traffic accident one
hour back.
Child is vomiting , also complains of headache.
Investigation of choice EMERGENCY CT BRAIN

34. Epidural hematoma
Skull fracture

35. Contd..
Neurosurgeon decided not to operate.
Child was managed conservatively , they also took 2
more CT brain scans.
Child was discharged with request to do brain
imaging after 6 weeks.
Which is the appropriate test..?
MRI brain is the more appropriate test here.

36. CT brain is the first modality in trauma.
It depicts hemorrhage and skull fractures well.
MRI is second line investigation in head trauma.
Fractures may be missed on MRI.

37. Case 2
5 year old child with headache , early morning
projectile vomiting.
You suspect an SOL.
MRI with contrast is the ideal test.

38. Posterior fossa midline tumor ,
most consistent with
medulloblastoma.
Also see hydrocephalus.

39. Case 3
7 year old boy with deterioration in school
performance , vision deterioration , reduced hearing.
? Leukodystrophy.
MRI brain is the investigation of choice.

40. Flair
Abnormality in posterior white
matter. Typical 3 zone
appearance on contrast scan.
MRI features consistent with
adrenoleukodystrophy.

41. Case 4
10 year old child with chronic headache.
Clinical examination- normal. Fundus- normal.
Parents insist on SCAN..
In this setting where clinical suspicion is low , both
MRI or CT may be used.

42. Case 5
First episode of right focal seizures followed by
generalized tonic clonic seizures.
Again MRI is the modality of choice

44. Contrast
MRI shows nodular
enhancing lesion ,
probably
tuberculoma.

45. How accurate is MRI ..?
Depending upon signal , enhancement pattern MRI
gives approximate diagnosis.
One needs to be watchful , plan for histopathology
confirmation when warranted.

46. How does cysticercus look on
MRI..?
Demonstration of
scolex in a cyst is
considered key in
cysticercosis.

47. Case 6
Premature baby in NICU , you sudden notice sudden
drop in hematocrit , bulging fontanelle.
You are not inclined to shift baby out of NICU.
Bedside NEUROSONOGRAM is the ideal test.

48. Coronal Sagittal

49. Coronal Sagittal
Intraventricular hemorrhage in
right lateral ventricle

50. Coronal Sagittal
Normal neurosonogram

53. Conclusion
Appropriate use of imaging is essential.
CT brain can be lifesaving., particularly in trauma. But
use it sparingly. Remember radiation effects.
MRI brain is modality of choice in most chronic
pediatric neuro conditions.
Less than 1 year think of neurosonogram.