Further information on the tests
Carotid duplex is also known as NIVA (Non invasive vascular assessment). This scan is primarily for assessing the blood flow in the arteries of the neck. The sonographer is able to calculate the velocity of blood flow and to determine the degree of narrowing in the blood vessel, if any. The test consists of applying a small probe to the side of the neck. The scan is usually performed to assess the risk of stroke. The carotid arteries in the neck are a common source of small clots, especially if there is a narrowing of the blood vessel due to atherosclerosis, known as a carotid artery stenosis.
Echocardiogram (Echo) is an ultrasound study of the heart. It gives information about the structure and function of the heart muscle and valves. An Echo is sometimes ordered when an individual has had a stroke or a Transient Ischaemic Attack to help exclude the heart as a source of embolus to the brain (eg thrombus in the atria or ventricles) or infective endocarditis, atrial myxoma or patent foramen ovale (PFO).
Electrocardiograph (ECG) is a recording of the electrical activity in the heart. Doctors can analyse multiple different components of the ECG to gain information about heart rate and rhythm, and to look for the presence of conditions affecting the heart. An ECG is a relatively simple test which involves sticking small electrodes on the chest and attaching them to a machine at the bedside. The machine analyses the heart’s electrical signals, picked up through the electrodes on the skin.
Ambulatory ECG. This test records the electrical activity of the heart when doing normal activites and is useful to capture paroxysmal AF (see below). Electrodes are stuck to the chest and connected to a small recorder (often called a Holter monitor). The electrical activity is recorded and can be recorded for several days. Duration of recording varies refer to local guidelines Patients are asked to complete a diary and record any symptoms they may have such as palpitations.
Atrial Fibrillation (AF) is the most common cardiac arrhythmia and involves the two upper chambers (atria) of the heart. Its name comes from the fibrillating (i.e. quivering) of the heart muscles of the atria, instead of a coordinated contraction. It can often be identified by taking a pulse and observing that the heartbeats are irregular. However, a stronger indicator of AF is the absence of ‘p’ waves on an ECG. Risk increases with age, with 10% of people over 80 having AF. Vascular health risk management (2015)
Paroxysmal atrial fibrillation (AF) is where a person has recurrent episodes of AF which stop in less than 7 days. In most cases of paroxysmal AF the episodes will stop in less than 24 hours.
MRI Scan (Magnetic Resonance Imaging) Unlike CT scan no radiation is used. An MRI machine consists of a very large and powerful magnet in which the patient lies. Magnetic signals or fields are sent into the body, and returning signals received to create an image. It can give a more detailed picture than a CT scan, it also takes longer to perform and involves lying still in an enclosed environment.
CT scan (Computed Tomography) A CT scan of the head is an accurate test to define brain structures and can identify brain matter, arteries, veins, cerebrospinal fluid filled ventricles and the bony architecture of the skull. The CT scan is performed with the patient lying flat. Intravenous contrast is not routinely used, but may be useful for evaluation of tumours, or cerebral infections. CT can identify early whether embolic or haemorrhagic cause of stroke, brain tumours and other malformations. After 7 days it is hard to differentiate a bleed from and ischaemic stroke using CT and MRI may be indicated.
“Young” stroke bloods. Normally done in people under 55years old with no obvious cause of stroke or TIA. Bloods include: Thrombophillia screen: Lupus inhibitor screen, Antithrombin, Protein C, Protein S, APC resistance, full coagulation screen, thrombin time, cardiolipin antibodies, Factor VIIIc, Factor V Leiden, Prothrombin 20210A gene mutations PCR’s. Autoimmune screen: Antinuclear antibodies (ANA), Antiphospholipid antibodies (APL), Anticardiolipin antibodies (ACL), Lupus anticoagulant (LA), Homocysteine, Syphilis serology (VDRL, FTA, others)
Vertebral Artery Angiogram. Used to assess the blood flow in the vertebral arteries. A thin catheter is placed through an artery, usually in the groin and carefully moved up through the main blood vessels and into an artery in the neck. Moving x-ray images help the doctor position the catheter. Once in place, a special dye (contrast material) is injected into catheter. X-ray images are taken to see how the dye moves through the artery and blood vessels of the brain. The dye helps highlight any blockages in blood flow.
