Radiographic dating definition
CT has the advantage of being available 24 hours a day and is the gold standard for hemorrhage. On CT 60% of infarcts are seen within 3-6 hrs and virtually all are seen in 24 hours.
The overall sensitivity of CT to diagnose stroke is 64% and the specificity is 85%.
Studies were performed to compare CT with MRI to see how much time it took to perform all the CT studies that were necessary to come to a diagnosis.
It was demonstrated that Plain CT, CTP and CTA can provide comprehensive diagnostic information in less than 15 minutes, provided that you have a good team.
Notice the involvement of the lentiform nucleus and insular cortex.
DWI is the most sensitive sequence for stroke imaging.
Hypoattenuation on CT is highly specific for irreversible ischemic brain damage if it is detected within first 6 hours (1).
This refers to hypodensity and swelling of the insular cortex.In this case the CT was normal and a CTP was performed, which demonstrated a perfusion defect.A CTA was subsequently performed and a dissection of the left internal carotid was demonstrated.It is a very indicative and subtle early CT-sign of infarction in the territory of the middle cerebral artery.This region is very sensitive to ischemia because it is the furthest removed from collateral flow.