Dr. Ajaya N Jha
nstitute of Neurosciences
To determine the most appropriate treatment for your stroke, your emergency team needs to evaluate the type of stroke you're having and the areas of your brain affected by the stroke. They also need to rule out other possible causes of your symptoms, such as a brain tumour or a drug reaction. Your doctor may use several tests to determine your risk of stroke, including:
Your doctor will ask you or a family member what symptoms you've been having, when they started and what you were doing when they began. Your doctor then will evaluate whether these symptoms are still present. Your doctor will want to know what medications you take and whether you have experienced any head injuries. You'll be asked about your personal and family history of heart disease, TIA or stroke. Your doctor will check your blood pressure and use a stethoscope to listen to your heart and to listen for a whooshing sound (bruit) over your neck (carotid) arteries, which may indicate atherosclerosis. Your doctor may also use an ophthalmoscope to check for signs of tiny cholesterol crystals or clots in the blood vessels at the back of your eyes.
You may have several blood tests, which give your care team important information such as how fast your blood clots, whether your blood sugar is abnormally high or low, whether critical blood chemicals are out of balance or whether you may have an infection. Your blood's clotting time and levels of sugar and key chemicals must be managed as part of your stroke care. Infections also must be treated.
Brain imaging plays a key role in determining if you're having a stroke and what type of stroke you may be experiencing. A CT scan uses a series of X-rays to create a detailed image of your brain. A CT scan can show a brain haemorrhage, tumours, strokes and other conditions. Doctors may inject a dye into your blood vessels to view your blood vessels in your neck and brain in greater detail (computerized tomography angiography).
An MRI uses powerful radio waves and magnets to create a detailed view of your brain. An MRI can detect brain tissue damaged by an ischemic stroke and brain haemorrhages. Sometimes your doctor may inject a dye into a blood vessel to view the arteries and veins and highlight blood flow (magnetic resonance angiography or magnetic resonance venography).
CT perfusion scanning is a non invasive medical test that helps physicians diagnose and treat medical conditions. CT perfusion is performed on a CT scanner. In computed tomography (CT) perfusion imaging, special computer software converts contrast enhanced CT images of the head into maps of blood flow, blood volume and tissue transit times throughout the brain. Perfusion images show which areas of the brain are supplied or perfused adequately with blood and provide detailed information on delivery of blood or blood flow to the brain.
CT perfusion is typically used to:
Angiography is a minimally invasive medical test that helps physicians diagnose and treat blood vessel diseases. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection is needed to produce pictures of blood vessels in the body.
CT angiography uses a CT scanner to produce detailed images of both blood vessels and tissues in various parts of the body.
An iodine-rich contrast material (dye) is usually injected through a small catheter placed in a vein of the arm. A CT scan is then performed while the contrast flows through the blood vessels to the various organs of the body. After scanning, the images will be processed using a special computer and software and reviewed in different planes and projections.
Doctors use this test to diagnose and evaluate many diseases of blood vessels and related conditions such as:
Though the scanning itself causes no pain, there may be some discomfort from having to remain still for several minutes and with placement of an IV. If you have a hard time staying still, are very nervous or anxious or have chronic pain, you may find a CT exam to be stressful. The technologist or nurse, under the direction of a physician, may offer you some medication to help you tolerate the CT scanning procedure.
You will feel a pin prick when the needle is inserted into your vein. You will likely have a warm, flushed sensation during the injection of the contrast materials and a metallic taste in your mouth that lasts for at most a minute or two. You may experience a sensation like you have to urinate; however, this is actually a contrast effect and subsides quickly.
When you enter the CT scanner room, special light lines may be seen projected onto your body and are used to ensure that you are properly positioned. With modern CT scanners, you will hear only slight buzzing, clicking and whirring sounds as the CT scanner revolves around you during the imaging process.
The technologist will always be able to see, hear and speak with you through a built-in intercom system.
After a CT exam, you can return to your normal activities.
Most patients complete CT angiography with no adverse events.
Angiography is a medical test that helps physicians diagnose and treat medical conditions related to blood vessels. In magnetic resonance angiography (MRA), a powerful magnetic field, radio waves and a computer produce the detailed images. MR angiography does not use ionizing radiation (x-rays).
MR angiography may be performed without or with contrast material. If needed, the contrast material is usually administered through a small catheter placed in a vein in your arm.
This examination is usually done on an outpatient basis and can be done on the Inpatient basis also.
You will be positioned on the moveable examination table. Straps and bolsters may be used to help you stay still and maintain the correct position during imaging.
Devices that contain coils capable of sending and receiving radio waves may be placed around or adjacent to the area of the body being studied.
If a contrast material will be used in the MRI exam, a physician, nurse or technologist will insert an intravenous (IV) catheter, also known as an IV line, into a vein in your hand or arm. A saline solution may be used. The solution will drip through the IV to prevent blockage of the IV catheter until the contrast material is injected.
You will be moved into the magnet of the MRI unit and the radiologist and technologist will leave the room while the MRI examination is performed.
If a contrast material is used during the examination, it will be injected into the intravenous line (IV) after an initial series of scans. Additional series of images will be taken during or following the injection.
When the examination is completed, you may be asked to wait until the technologist or radiologist checks the images in case additional images are needed.
Your intravenous line will be removed.
MRI exams generally include multiple runs (sequences), some of which may last several minutes.
The entire examination is usually completed in approximately 60 minutes once imaging has started.
TCD is a non-invasive ultrasound method used to examine the blood circulation within the brain. During TCD, sound waves, inaudible to the human ear, are transmitted through the tissues of the skull. These sound waves reflect off blood cells moving within the blood vessels, allowing the radiologist to calculate their speed. The sound waves are recorded and displayed on a computer screen.
Your doctor will recommended that you have this test to determine the amount of blood flow to certain areas of your brain. The TCD ultrasound can also be used to monitor blood flow in the brain during surgical procedures. TCD ultrasound images help in the diagnosis of a wide range of conditions affecting blood flow to the brain and within the brain.
A doctor will ask you to recline in a chair or lie on a bed. You will be asked to move into different positions during the test. It is important to do exactly as the doctor tells you. A gel that washes off with water will be put on different areas of your scalp. Ultrasound does not travel well through air, so the gel is used to keep air bubbles from blocking the sound waves. The gel will feel cold on your scalp.
Usually 3 areas of your head are tested: your temples, your closed eyes and the back of your skull. You may feel a slight pressure as the transducer is moved over these areas. The transducer makes blood flow audible. During the test, you may hear sounds of the blood flowing through your arteries. The doctor will adjust the sound volume of the speaker to locate the blood vessels to be studied. The test usually lasts 15 to 60 minutes.
Almost no risk, studies have shown ultrasound is not hazardous. There are no harmful side effects. In addition, ultrasound does not use radiation, as X-ray tests do.
The term "ultrasound" applies to all sound waves with a frequency above the audible range of normal human hearing, about 20 kHz. Higher frequency sound waves have capability of reflecting or scattering from smaller structures and are more readily absorbed in tissue
Ultrasound imaging, also called ultrasound scanning involves the use of a small transducer (probe) and ultrasound gel to expose the body to high-frequency sound waves. Ultrasound is safe and painless and produces pictures of the inside of the body using sound waves. Ultrasound examinations do not use ionizing radiation (as used in x-rays). Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.
An ultrasound of the body's two carotid arteries, which are located on each side of the neck and carry blood from the heart to the brain, provides detailed pictures of these blood vessels and information about the blood flowing through them.
A Doppler ultrasound study is usually an integral part of a carotid ultrasound examination. Doppler Ultrasound: An application of Doppler Ultrasound is used to detect moving blood cells or other moving structures and measure their direction and speed of movement. The Doppler effect is used to evaluate movement by measuring changes in frequency of the echoes reflected from moving structures.
The carotid ultrasound is most frequently performed to detect narrowing or stenosis, of the carotid artery, a condition that substantially increases the risk of stroke.
The major goal of carotid ultrasound is to screen patients for blockage or narrowing of their carotid arteries, which if present may increase their risk of having a stroke. If a significant narrowing is detected, a comprehensive treatment may be initiated.
A technician (sonographer) conducts the test with a small, hand-held device called a transducer. The transducer emits sound waves and records the echo as the waves bounce off tissues organs and blood cells.
A computer translates the echoed sound waves into a live-action image on a monitor. In a Doppler ultrasound, the information about the rate of blood flow is translated into a graph.
A carotid ultrasound usually takes about 30 minutes.
You'll likely lie on your back during the procedure. The ultrasound technician (sonographer) may gently adjust the position of your head to improve access to the side of your neck.
The sonographer will apply a warm gel to your skin above the site of each carotid artery. The gel helps eliminate the formation of air pockets between your skin and the transducer. The sonographer then gently presses the transducer against the side of your neck in order for the instrument to send and receive sound waves.
You shouldn't feel any discomfort during the procedure. If you do, tell the sonographer.
Doppler ultrasound permits real-time viewing of blood flow that cannot be obtained by other methods. Doppler ultrasound has proved a boon in all areas of ultrasound, aiding in the evaluation of the major arteries and veins of the body, the heart and in obstetrics for foetal monitoring.
Doppler ultrasound images can help the physician to see and evaluate:
You should wear comfortable, loose-fitting clothing for your ultrasound exam. You may need to remove all clothing and jewellery in the area to be examined.
A loose-fitting, open necked shirt or blouse is ideal.
Ultrasound examinations are very sensitive to motion and an active or crying child will slow the examination process. To ensure a smooth experience, it would be beneficial to explain the procedure to the child prior to the exam. You may bring a book to read to the child to ease anxiety. Ultrasound departments often have a television in the examination room and the child's favourite show may be played if there are no other available distractions.
No other preparation is required.
Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships and fishermen. When a sound wave strikes an object, it bounces back or echoes. By measuring these echo waves, it is possible to determine how far away the object is and its size, shape and consistency (whether the object is solid or filled with fluid).
In medicine, ultrasound is used to detect changes in appearance of organs, tissues and vessels or detect abnormal masses, such as tumours.
In an ultrasound examination, a transducer both sends the sound waves and receives the echoing waves. When the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves into the body. As the sound waves bounce off of internal organs, fluids and tissues, the sensitive microphone in the transducer records tiny changes in the sound's pitch and direction. These signature waves are instantly measured and displayed by a computer, which in turn creates a real-time picture on the monitor. One or more frames of the moving pictures are typically captured as still images. Small loops of the moving "real time" images may also be saved.
Doppler ultrasound, a special application of ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of blood cells causes a change in pitch of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and creates graphs or colour pictures that represent the flow of blood through the blood vessels.
Ultrasound examinations are painless, fast and easily tolerated by most patients.
After you are positioned on the examination table, the radiologist or sonographer will apply some warm water-based gel on your skin and then place the transducer firmly against your body, moving it back and forth over the area of interest until the desired images are captured. There is usually no discomfort from pressure as the transducer is pressed against the area being examined.
If scanning is performed over an area of tenderness, you may feel pressure or minor pain from the transducer.
It may be necessary to tilt or rotate your head for the best exposure, as the transducer is swept over the entire length of your neck on both sides to obtain views of the artery from different perspectives. It also helps to keep your arm and shoulder down. Your head will be supported to keep it still.
If a Doppler ultrasound study is performed, you may actually hear pulse-like sounds that change in pitch as the blood flow is monitored and measured.
Once the imaging is complete, the clear ultrasound gel will be wiped off your skin.
After an ultrasound examination, you should be able to resume your normal activities immediately.
A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyse the images and send a signed report to your primary care physician or to the physician or other healthcare provider who referred you for the exam, who will share the results with you. In some cases the radiologist may discuss results with you at the conclusion of your examination.
Follow-up examinations may be necessary and your doctor will explain the reason why another exam is needed. Sometimes a follow-up exam is done because a suspicious or questionable finding needs clarification with additional views or a special imaging technique. A follow-up examination may be necessary so that any change in a known abnormality can be monitored over time. Follow-up examinations are sometimes the best way to see if treatment is working or if an abnormality is stable over time.
Carotid ultrasound may be difficult or impossible if a patient has a dressing covering a wound or surgical scar in the neck.
An occasional patient is difficult to examine because of the size or contour of the neck.
Calcium deposits in the wall of the carotid artery may make it difficult to evaluate the vessel.
A small amount of soft plaque that produces low-level echoes may go undetected.
Ultrasound cannot visualize the entire length of the vessel because the last portion of the carotid artery travels though the bone at the base of the skull. For a more complete assessment, patients may need to undergo a CT or MRI of the carotid arteries.
A cerebral angiogram (also known as an arteriogram) is a diagnostic procedure that provides images of the blood vessels in the brain and/or head. The test is performed to find blocked or leaking blood vessels. This test can help to diagnose such conditions as the presence of a blood clot, fatty plaque that increases the patient's risk of stroke, cerebral aneurysm or other vascular malformations.
A cerebral angiogram requires that a special dye be injected into the arteries of the head or brain. Under the direction of an expert physician, this procedure is done by inserting a thin tube (a catheter) through a blood vessel, (most often starting in the patients' thigh) all the way up to the head and/or brain. When the catheter is in the correct position the dye is them injected. At this point the cerebral angiogram can generate the images of the blood vessels.
Prior to the angiogram, patients are asked to change into a hospital gown. It is not unusual for blood and urine samples to be collected or an electrocardiogram (EKG) or chest x-ray to be performed. In the nursing unit, a mild sedative and fluids are administered through an IV. Medication is available for pain and anxiety.
In the procedure room, the patient is positioned on an x-ray table. A blood pressure cuff, heart monitor and pulse oximeter are placed on the patient to monitor their vital signs. A sterile drape is placed over most of the patient's body. The patient's head is secured to the table with straps to keep it still.
The area where the catheter (small tube) will be inserted is washed and a local anesthetic is given to prevent pain. The catheter is usually inserted into an artery in the groin, but an artery in the thigh, neck or arm may be used instead. A tiny incision is made into the artery and a guide wire is inserted and carefully fed through the artery. The catheter tube is slid over the guide wire into the artery. Using fluoroscopy (an advanced imaging tool), the physician is able to watch the catheter as it is maneuvered into the blood vessels of the brain. When the catheter is correctly positioned, the contrast dye is injected. More than one injection of dye may be necessary to complete the evaluation.
During the injection of the contrast dye, some patients report a flushed warm feeling, nausea or get a salt or metallic taste in their mouth. This is normal and should be reported to the physician. When the x-rays are taken, the patient is given special instructions for breathing and swallowing. The patient may be asked to do simple movements or speak during the test.
When the test is finished, the catheter is removed and pressure is applied to the incision for 15-20 minutes to stop bleeding. When the bleeding stops, a thick dressing is placed on the incision. The patient is then moved to an observation area.
Cerebral angiography is most frequently used to identify or confirm problems with the blood vessels in the brain.
Your doctor may order this test if you have symptoms or signs of:
It is sometimes used to:
In some cases, this procedure may be used to get more detailed information after something abnormal has been detected by an MRI or CT scan of the head.
This test may also be done in preparation for medical treatment (interventional radiology procedures) by way of certain blood vessels.
While the patient is in the observation area, nurses check vital signs, the incision site and attend to all of the patient's needs. It is necessary for the patient to lie still with his or her head flat for six to eight hours. Gradually the patient is allowed to get out of bed with assistance; lightheadedness and dizziness may occur if the patient gets out of bed too quickly.
When the patient is released home, he or she is given discharge instructions. These 'at home' instructions include:
The chance of any complication with a cerebral angiogram is small. However, it is important to be aware of the possible risks, which include internal bleeding, damage to a blood vessel, infection, allergic reaction to the contrast dye and stroke. Of course your physician will be carefully monitoring for any complications and is fully trained to respond if one arises.
Cerebral angiograms are used to investigate stroke, tumours, bleeding, vascular malformations and other suspected vascular disorders affecting the brain.
A staff person from the hospital will call you a few days before the procedure with preparation instructions that will include dietary restrictions necessary for sedation or anaesthesia. It is very important that you follow all of these instructions or the procedure may need to be rescheduled. When you arrive at the hospital:
The interventional radiologist or neuro-radiologist will talk to you about the procedure and ask you to sign the consent form
A tiny incision will then be made by the radiologist usually at the crease of the hip, under the effect of general or local anaesthesia.
Through this incision, the radiologist will insert a needle into the appropriate blood vessel to provide access for insertion of a short arterial sheath
The sheath provides safe access for a long, thin tube (the catheter)
Under X-ray guidance, the radiologist will guide the catheter to the blood vessel being studied and will then inject a special contrast solution through the catheter so that he or she can see your blood vessels more clearly
When the angiogram is finished, the radiologist removes the catheter and sheath .A small bandage will be placed over the tiny incision.
The radiologist will speak with you after the procedure and explain the findings and results.
Cerebral angiograms are considered minor surgical procedures. They are generally safe, but as with any surgical procedure, carry some risk of complication. The doctor will explain potential side effects and complications before you are asked to consent to the procedure.
An echocardiogram uses sound waves to create detailed images of your heart. An echocardiogram can find a source of clots in your heart that may have travelled from your heart to your brain and caused your stroke.
In this test, your doctor inserts a flexible tube with a small device (transducer) attached in your throat and down into your oesophagus - the tube that connects the back of your mouth to your stomach. Because your oesophagus is directly behind your heart, a trans-oesophageal echocardiogram can create clear, detailed ultrasound images of your heart and any blood clots.
There are no known risks involved in this procedure.
There is no special preparation for the test. For a TEE, you will be asked not to eat or drink for several hours before the test.
You will be asked to remove your clothes from the waist up and lie on an examination table on your back. Electrodes will be placed on your chest to allow for an ECG to be done. A gel will be spread on your chest and then the transducer will be applied. You will feel a slight pressure on your chest from the transducer. You may be asked to breathe in a certain way or to roll over onto your left side.
This test is done to evaluate the valves and chambers of the heart in a non-invasive way. The echocardiogram allows doctors to diagnose, evaluate and monitor:
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