A Digital Subtraction Angiogram (DSA) or femoral cerebral angiogram, or radial cerebral angiogram involves using a needle and wire to introduce a long plastic tube called a catheter into the arteries, then using contrast dye and x-ray images to guide the catheter into the arteries going to the brain, then taking x-ray pictures with injection of contrast dye. This test offers the highest level of detail for brain aneurysms, AVMs, and fistulas.

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This procedure can be done from the wrist or the leg. There are certain situations in which one site is preferred. At this point most of the time this procedure can be done through the artery in the wrist reducing the time needed to stay in the hospital.

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Prior to the procedure you will get routine blood tests to ensure wee are safe to proceed with the procedure. You cannot eat or drink anything after midnight the day before the procedure. You are expected to arrive 1 hour prior the time of your procedure. You are expected to check into the Medical Intervention Unit (MIU) which is on the first floor of the hospital. 

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When you arrive you will change into a hospital gown. A nurse will ask you some questions and place an intravenous line (IV) into your vein. When the procedure room is ready you will be brought to the angio suite. There you will be asked to lay flat on a table. You will be given medication that makes you sleepy however you will not be unconscious. 

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You will be given numbing medication in area of planned entrance (either the wrist or upper thigh). The procedure takes about an hour. When the catheter is in place to take pictures. The technologist will let you know and give you specific breathing instructions in order for the pictures to be crisp. 

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When the pictures are completed the catheter will be removed. If we go through the wrist we will place a special inflatable bracelet on your wrist which will stay on for 30 minutes. If we go through the leg, then we will put pressure on your upper thigh for 10-15 minutes after the tubes are removed. 

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When going through the leg after the procedure you will have to lay flat for 4 hours. 

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When going through the wrist there are no such restrictions. 

Magnetic resonance (MR) scans use powerful magnets to take detailed pictures of the brain. MRI of the brain gives us detail about the brain itself. MR angiogram (MRA) gives us detail about the arteries of the brain. Both of these kinds of tests can enhanced by the injection of gadolinium contrast dye through an intravenous line. 

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This test takes about an hour and can be done at any imaging center that performs MRI scans. You will have to lie flat on a table, and keep very still. The procedure is not painful in any way however the machine can make load noises, and the tube which you lie in can be small which for some people who are claustrophobic can make them uncomfortable. 

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MRA scans are helpful for people who are watching aneurysms for changes, or for people who have had their aneurysms treated already. MRA is the most common kind of picture used to screen for aneurysms however it does not offer the same level of detail as a cerebral angiogram.

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MRI of the brain is often useful for persons with very large aneurysms, or for those who have brain AVMs.

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People with impaired kidney function cannot have gadolinium contrast dye. People with certain electronic or metallic implants like defibrillators or spinal cord stimulators may not be able to get MRI scans. Please be sure to let your doctor know if you have these conditions prior to getting an MRI scan.

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CT angiogram (CTA) is a kind of picture of the brain and arteries of the brain that uses a kind of iodine based contrast dye. CTA shows less details about the brain than MRI however can give a higher level of detail than MRA. While the detail is higher than MRA, it is still not as high a detail as a cerebral angiogram. 

 

A CTA can be done faster than a MRA scan, and the tube in which the test is done is larger therefore there is less concern for claustrophobia. 

 

For people with impaired kidney function, you may not be able to get this kind of study done. Also if you have a history of allergic reaction to contrast dye then you need to inform your doctor so you can be given special medication to prevent an allergic reaction.