CT scans and MRIs use different techniques to image the brain. CT scans use X-rays that are absorbed at different levels by tissues, allowing tissues to be classified based on their density compared to brain tissue. MRI uses different pulse sequences optimized for T1-weighted or T2-weighted images to highlight tissues based on their relaxation times. Both techniques provide detailed images of the brain that can help doctors diagnose neurological conditions.

1. UNDERSTANDING
CT SCAN & MRI
BRAIN
DR. FARRUKH JAVEED
CONSULTANT NEUROSURGEON
JPMC, KARACHI.

2. TECHNIQUE.
Slice
thickness may
vary, but in
general, it is
between 5 and
10 mm for a
routine Head
CT

4. • X-RAYS ARE ABSORBED TO DIFFERENT DEGREES
BY DIFFERENT TISSUES
• CT findings described as densities-
isodense/hypodense/hyperdense.
– Higher the density = whiter is the appearance
– Lower the density = darker the appearance
• Brain is the reference density
– Anything of the density as brain= isodense
– Higher density than brain= hyperdense ( skull is the
best example)
– Anything darker (lower density) than brain=
hypodense( CSF and air are classical examples)

19. IMAGE SECTION

38. TEST

44. MRI

45. T1W IMAGE
TE=<60 TR=<2000

46. T2W IMAGE
TE=>60 TR>2000

47. FLAIR IMAGE
TE>60
TR>2000

50. THANK YOU