lunedì 31 dicembre 2007
Occlusion of the left internal carotid artery with subsequent large left MCA acute infarction
CT head demonstrates increased density of the left MCA, compatible with a dense MCA sign. Additionally, there is subtle hypodensity of the left lentiform nucleus and left sub insular cortex. MR head demonstrates restricted diffusion in a left MCA distribution. MR angiography demonstrates absence of flow in the left internal carotid artery and left middle cerebral artery.
Diagnosis: Occlusion of the left internal carotid artery with subsequent large left MCA acute infarction
Cerebrovascular infarction most commonly involves the MCA distribution.
Ischemic stroke is far more common than hemorrhagic stroke, accounting for approximately 85% of cases.
Third leading cause of death in the United States.
Non-contrast head CT is the initial study of choice to evaluate for signs of hemorrhage.
Therapeutic window for t-PA (tissue plasminogen activator) thrombolysis is 3 hours from symptom onset.
Non-contrast CT usually is negative within the first 6 hours of onset. From 6-12 hours, sufficient tissue edema occurs to cause regional hypodensity.
Diffusion-weighted MRI can show changes of ischemic stroke in as little as 30 minutes after symptom onset.
Signs of MCA infarction include the dense MCA sign, and insular ribbon sign.