CT SCAN(BRAIN)

Dr. Sumit Kr. GhoshAsst. Professor

Department of MedicineMedical College & Hospital, Kolkata

COMPUTED TOMOGRAPHY

Godfrey Hounsfield

Hounsfield unit / number

-1000Black Air

+ 1000WhiteBone

0

Water

HYPODENSE ISODENSE HYPERDENSE

Black White

1. Air (air sinuses)

Brain parenchyma 1. Bone

2. CSF (ventricles/ sulci/cisterns)

2. Calcification ( Choroid plexus, pineal gland, basal ganglia, granuloma , tumour)

3. Fat (retro-orbital) 3. Heomarrhage

4. Infarct 4. Blood vessels

5. Edema 5. Ring –enhancing lesion

Hypo/hyper -intensityHypo/hyper-echoic

Conventional : thik slice : 7-10 mmHRCT : thinner slice : 1-2 mm