CT Guided Injections
What is a CT Guided Injection?
CT Guided Injections are procedures where a CT scanner is used to guide a needle to a location in the body, so that a medication (usually steroid and local anaesthetic) can be given directly to help treat a number of conditions. CT Guided Injections in the spinal region may help to confirm that compression or irritation of a particular nerve is responsible for your symptoms, and aims to provide relief from neck, back, leg or arm pain.
Why Consider CT Guided Injections
CT-guided injection procedures may be particularly beneficial to patients who have:
- a history of spinal surgery with instrumentation, such as screws or rods, or bone grafts that may obscure or distort spinal anatomy
- a focal problem such as an inflamed joint or muscle/tendon that needs imaging guidance to ensure the medication is accurately delivered.
What are the Benefits of CT Guided Injections
The anti-inflammatory is long lasting - with the effects up to 3 months - however it may not begin working for several (2-7) days following the injection.
CT-guided injections offer several advantages compared to the technique most commonly used to guide injections, called X-ray fluoroscopy. Some injections are given with no guidance, reducing the probability the medication is delivered to the correct location.
Your radiologist is able to
- more accurately visualize anatomy — bones, nerves, joints, discs, soft tissues and surgical instrumentation — that can't be seen using X-ray-based fluoroscopy, often down to millimeter accuracy.
- inject smaller smaller amounts of medication into the targeted area with unparalleled precision and safety.
Preparation for a CT Guided Injections
If you
- have previous X-Ray, CT or MRI films available, please bring these with you if you have them.
- are on any medication or have diabetes and are on insulin, take your usual medicines and diet.
- Use any medication to thin your blood (eg. Warfarin, Aspirin or Clopidogrel), please advise us,
- Have an iodine allergy, or are pregnant or breastfeeding, please advise us,
Your doctor may request this procedure to be performed with sedation, in which case you will be required to fast (not eat or drink anything) before the procedure, and a short stay hospital admission will be necessary.
On the Day of a CT Guided Injections
It will be necessary for somebody to drive you home but you may eat and drink normally.
Before the procedure, you may be asked to change into an examination gown for your comfort, and to ensure clothing does not affect the images.
You may also be asked to remove jewellery, eye-glasses and any metal objects that might interfere with the imaging.
During a CT Guided Injections
A CT Guided Injection normally takes around 15 minutes.
- You will lie on the CT table.
- Your skin will be cleaned with antiseptic where the needle will be given,
- a local anaesthetic will be injected
- The radiologist inserts a fine needle into the location that your doctor has asked us to inject using an aseptic technique (strict infection control practices).
- The CT machine is used to guide the placement of the needle safely and accurately into the correct position,
- a small amount of X-ray contrast or air may be injected to help confirm the correct location.
During the injection procedure you will undergo high-resolution, cross-sectional diagnostic CT, which may reveal other sources of pain or disease in adjacent discs or facets that weren't recognized on routine scans.
A long-lasting anaesthetic and a long-acting steroid are usually injected together.
After a CT Guided Injections
Recovery after a CT Guided Injection should last only for a few hours. For those patients that undergo a nerve root injection, numbness in the legs or arms may occur for several hours, but will resolve once the local anaesthetic in injection wears off.
The local anaesthetic may give pain relief initially but will wear off after a few hours and the pain may return.
The effect of the steroid can last for a week, several months or years. Sometimes there is no pain relief from the injection. It can take several days for the steroid to begin to work and may take up to 2 weeks for it to have maximum effect.
Avoid strenuous activity for at least 48 hours after the injection.
If required, a simple analgesic such as paracetamol (Panadol) or anti-inflammatory should be sufficient. An ice pack may also provide some relief.
Possible Risks with a CT Guided Injections
Infection is a potential and serious side effect. If you notice any fever or redness, swelling, or increased pain at the injection site after the first 2 days, notify your referring doctor or immediately call the clinic where the injection was performed.
Side effects may include:
- Worsening of symptoms and weakness for 24-48 hours.
- Increased blood sugar levels in diabetics.
- Insomnia, flushing and palpitations.
- Local bruising and soreness. Infection is an uncommon, but serious side effect.
Serious side effects causing permanent neurological damage can occur extremely rarely.
If X-ray contrast is given, there is a small risk of an allergic reaction, which may include flushing, hives and difficulty breathing. Severe reactions are rare, and a life-threatening reaction is extremely rare (1 in 170,000).
