Cerebro-vascular stroke

1-First of all, the investigation of a case suspected to be suffering from a cerebro-vascular stroke should be evaluated primarily by CT and not by MRI.

2-MRI is not the first step for evaluation of the acute stage.

3-If you are suspecting that the patient is suffering from an infarction or bleeding in the brain, CT is the investigation of choice.

4-Hyper dense lesion is the lesion shows density more than that of the brain parenchyma.

Hypo dense lesion is the lesion shows density less than that of the brain parenchyma.

Iso dense lesion is that lesion shows density similar to that of the brain parenchyma.

This image is an example of a hypo dense lesion in the brain representing infarction.

This image represents hemorrhage which is of density more than that of brain tissue.

This image represents a sub acute sub dural hematoma with density similar to that of the brain

5-In case of the lesion similar in density to that of the brain, you can not see the lesion itself, but you see the effect of this lesion, which is in the example above, shift of the midline structure and the compression of the epsilateral ventricle and dilatation of the contra lateral ventricle(not shown in the previous image).

6-CT density (HU) :

Hypo dense lesions

-Brain parenchyma 30-40 HU.

-SCF                          0-15 HU.

-Brain edema           20 HU.

-Infarction               25 HU.

-Cyst                        according to its content.

-Fat                           > -300 HU.

-Air                          -500 HU.

Hyper dense lesions

-Recent blood             60-90 HU.

-Calcification              > 100 HU.

-Some tumors.

-Fluids with high protein contents.