Excellent

1. CNS IMAGING
DR. KELASH KUMAR
CONSULTANT RADIOLOGIST
ASSISTANT PROFESSOR
HAMDARD COLLEGE OF MEDICINE AND DENTISTRY

2. Outlines
 Normal anatomy
 Modalities for imaging CNS
 CT Scan (Basic principles and common uses)
 CT scan versus MRI
 MRI ( Basic Principles and indications)
 Common cases

3. Normal anatomy
 CNS is main part of human body which controls different body parts and
mind. It consists of brain and spinal cord.
 Brain has three main parts two cerebral hemispheres, brainstem and
cerebellar hemispheres.
 Cerebrum is largest part. Cerebellum lies below cerebral hemispheres
while brainstem is the relay center connecting cerebrum and cerebellum to
the spinal cord.
 Intelligence, creativity, emotions and memory are important functions of
brain.

5.  Sulci are fissures in the brain tissue.
 Gyri are elevated hill areas between sulci.
 Meninges:
 Dura, arachnoid and Pia.
 Dura and pia are vascular while arachnoid is avascular layer.

7. Modalities for CNS Imaging
 X ray
 CT scan
 MRI

8.  X ray is used in trauma but it has been replaced by CT scan in emergency
cases of trauma.
 CT scan is based on X ray tube on one side and detectors on other side of
gantry which rotates 360° around the patient continuously sending and
detecting information on attenuation of X rays as they pass through the
body.
 Finally, a computer manipulates and integrates the acquired data and
assigns numerical values based on the subtle differences in x-ray
attenuation.

9. Head CT Protocol

10. Terminology
 Hyperattenuating(hyperdense)
 Isoattenuating (Isodense)
 Hypoattenuating (Hypodense)
 Attenuation:
 Measured in Hounsfield units Scale ranging from -1000 to +1000 H.U
 -1000 is air, Fat is -100 HU, 0 is water, Fluid is 20:40 H.U, Blood 60-70HU,
+1000 is cortical bone & calcification

12. DIFFERENT PLANES

14. Difference between CT scan and MRI

15. BRAIN CT MRI

25. Infarction