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Acute Stroke

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The initial signs of acute stroke on nonenhanced CT are subtle but signs that may be visible would include: loss of distinction between white and grey mater, hypodensities in the brain parenchyma, loss of appearance of sulcal markings on surface of the brain and obscured delineation of basel ganglia. The presence of hyerdensity in a main artery may imply thrombus in a main cerebral artery. In the absence of contrast this sign has a high specificity but a low sensitivity for middle cerebral artery occlusion. Overall a nonenhanced CT brain in acute stroke has a sensitivity as low as 26%. If more than 30% of the distribution of the middle cerebral artery shows evidence of acute strioke thrombolysis is contraindicated. The Alberta Stroke Program Early CT Score ( ASPECTS) can be used to categorise patients as suitable or not for thrombolysis. In this system the…show more content…
This has the effect to produce contrast between vascular structures and surrounding soft tissues. Depending on the timing of imaging after IV injection arteries veins or soft tissues are highlighted. For the purposes of acute evaluation of stroke as is described above an initial non contrats CT scan is performed , followed immediately afterwards by a CT angiogram to evaluate vascular structures from aortic arch to the vertex. This technique is very accurate for diagnosing occlusion of any of the cerebral arteries be they intracranial or extracranial. It will also diagnose the presence of stenosis or dissection of the carotid arteries or middle cerebral arteries. From these images reconstructions of intracranial and extracranial cerebral arteries can be made. A contrast enhanced cerebral angiogram is essential for the planning of thrombectomy as it will provide precise anatomy of cerebral arteries, any stenosis or thrombus in each
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