CT

Question 1

Describe the CT characteristics of hemorrhage within the brain.

Intracranial hemorrhage: principles of CT and MRI interpretation. Eur Radiol (2001)

Answer 1

Increased signal from globin products (high in protein - high in attenuation)
Hyperacute - will be iso to slightly increased density to the surrounding brain (30-40HU) due to accumulation of RBC, WBC, protein rich serum, platelets

Acute (early hours)- clot forms - hyperintense (60-80HU) fibrin and globin clots. Enhancement can occur during this stage.

Mature hematoma (days) - retraction will occur resulting in HU of 80-100. Hypodense halo surrounding clot from edema.

As clot resorbs (days-weeks) - will decrease in attenuation by 0.7-1.5HU per day.

Question 2

Differences between epidural and subdural hemorrhage

Intracranial hemorrhage: principles of CT and MRI interpretation. Eur Radiol (2001)

Answer 2

Epiducarl: Biconves on coup side - usually associated with fractures.
Does not cross suture lines
Can cross midline - not limited by the falx cerebri

Subdural: crescent shape on the counter-coup side. No necessarily seen wtih fractures.
Does not cross suture lines
Limited by the falx cerebri - cannot cross midline.

Question 3

What are the stages of hemorrhage graded on MRI? What length of time does each stage represent?

Intracranial hemorrhage: principles of CT and MRI interpretation. Eur Radiol (2001)

Answer 3

Hyperacute: first few hours
Acute: 1-3days
Early subacute: 3-7 days
Late subacute: 7-14 days up to 1m
Chronic: 1 months - years