Based on the initial assessment, Angela has probably had an acute stroke and is within the time window when thrombolysis (0-4.5 hours) or thrombectomy (0-6 hours) is likely to improve her recovery.
The priority now is to get a non-contrast CT brain scan to exclude a bleed, and to determine whether she has a blocked artery which might be treatable with thrombectomy with a CT angiogram (CTA).
In a patient with a hyperacute stroke the CTA may not only show a blocked artery amenable to thrombectomy but also help determine the cause of the stroke, and even whether later treatment (i.e. after 4.5 hours) with thrombolysis might be effective.
CT angiograms (CTA). Please indicate whether the following statements about CT angiograms are True or False.
True
CTA can show a blocked artery suitable for thrombectomy – True – this is the main reason for doing a CTA.
CTA can show collaterals which if present may extend the time window for treatment – True – the presence of collaterals i.e. blood vessels which take blood around a blockage, indicates that the patient may benefit from thrombolysis or thrombectomy even beyond the normal time windows of 4.5 and 6 hours respectively.
CTA can show a carotid stenosis suitable for carotid endarterectomy – True – the CTA shows the carotid artery in the neck. If the patient has a severe narrowing of the internal carotid artery on the side of ischaemic stroke, and makes an early recovery, their risk of recurrent stroke may be reduced by an early carotid endarterectomy.
CTA can show a carotid or vertebral artery dissection – True – a CTA may show the dissection flap, or narrowing which indicates that a dissection has caused the stroke. This is likely to change the approach to subsequent treatment to reduce the risk of recurrent strokes.
CTA may show the cause of a intracranial bleed – True – the CTA may show a saccular (berry) aneurysm, an arterio venous malformation or other cause of a haemorrhagic stroke.
CTA adds a few minutes to the scan time – True – A CTA will add 10-15 minutes to the time it takes to complete the scans. If the bolus of thrombolysis can be given after the non-contract CT, and whilst they are being prepared for the CTA, the CTA will not delay the thrombolysis treatment.
False
CTA reduces the patient’s radiation exposure – False – a CTA of both the neck and intracranial vessels increases the radiation exposure 3 fold. A CT perfusion scan will increase the exposure 5 fold.
Any stroke physician or general radiologist is able to interpret a CTA – False – interpretation of CTA requires additional training. This is available for free at Edinburgh Imaging: Acute CTA for Thrombectomy in Stroke (ACTATS)
CTA is free of any risks – False – CTA involves injection of contrast which can cause serious reactions in a very small proportion of people.
CTA should be routinely requested for any patient with a possible stroke – False – CTA will usually contribute to the care of patients where thrombolysis or thrombectomy are being considered, but should only be carried out in other patients where it would influence management.
