St Vincent's Clinic Medical Imaging & Nuclear Medicine

Imaging Guided Injections

Your doctor may request imaging guidance for more accurate and safe placement of needles into various joints or soft tissues in the body in order to deliver of a variety of medications including local anaesthetics, cortisone, joint viscosupplementation (eg Synvisc), or for re-administration of your own blood products such as in platelet rich plasma injections.

Platelet Rich Plasma Injections

What is Platelet Rich Plasma?

Platelets are a component of blood that promotes healing. They are an integral part of wound repair and to help stop bleeding. They act by releasing certain growth factors which stimulate regeneration of connective tissue, ingrowth of blood vessels and inflammation.

Before the procedure, we take your blood and centrifuge it to isolate and concentrate these platelets into a small volume termed ‘platelet rich plasma’ which is then injected back into damaged tissue (usually tendons or joints) under imaging guidance. Local anaesthetic is used, however the procedure may still be uncomfortable during and after the procedure for up to a few days.

Although early studies point to the majority of patients benefitting from these injections, results are not 100%.

What do I need to prepare for this?

As platelets last in the blood stream between 5-9 days, it is important not to take any medications that would inactivate platelets for up to 10 days before your procedure. Such medications include aspirin, non-steroidal anti-inflammatories (e.g. Mobic, Nurofen, Voltaren, Celebrex) and Plavix. Please inform the booking staff if you take these medications or if you take cortisone.

Other conditions you should tell us before booking for a PRP injection:

  • Low platelet count
  • Current infection
  • Blood disorders (eg thrombocytopenia)
  • Possible pregnancy

What happens after the procedure?

After the local anaesthetic wears off, the most common response is initial discomfort within a few hours. We can prescribe a paracetamol based analgesic to help with this. You may also apply ice to the area if needed. The discomfort is expected to resolve within a few days and it is important to rest the body part injected for 1 week, however, normal daily activities are acceptable. A beneficial effect from the procedure is typically delayed, and may not be felt for 2-3 weeks following the procedure.

It is important in the first 2 weeks after the procedure to try to avoid non-steroidal anti-inflammatories, aspirin or Plavix if at all possible.

We recommend you do not drive yourself home and have someone with you to accompany you home.

What are the possible side effects?

Given that we are using your own blood, the risk of reactions or infection is exceedingly rare. The most common “effect” for the first few days is pain at the site of the injection. Scarring or damage to the site is also rare.

The type of imaging modality used to guide needle placement depends on various factors such as location in the body, joints versus soft tissues, accessibility, and doctor preference.

In general, whatever imaging modality chosen, the procedure begins with preliminary scans for planning, followed by a series of safety questions. The doctor will also discuss with you the procedure prior to commencement – this is a good time to ask questions.

Your skin will be sterilised and local anaesthetic administered, followed by a series of needle adjustments with images taken to assess needle positioning. The local anaesthetic will sting initially but pain relief usually takes a matter of seconds to occur.

During the procedure, discomfort may be experienced, but should there be any excessive pain or unusual symptoms during the procedure, please inform the doctor performing the procedure immediately.

There is a chance of numbness or weakness following the procedure, which is almost always temporary (due to the local anaesthetic), and therefore driving is NOT advised for the remainder of the day.

Will I need another injection?

Depending on your referring doctor, you may require subsequent PRP injections. This is typically performed within 4 weeks of an initial injection to help boost the effect of the first injection.

For further information please see

PRP Injection Brochure

Cortisone injections

What is cortisone?

Cortisone is a strong anti-inflammatory medical which can be Injected to reduce pain experienced in a number of joints in the body and the spine. Cortisone injections are performed by radiologists (specialist doctors) where chronic pain cannot be reduced by other means, and are not a cure for the underlying cause of pain but are a technique used to provide symptom relief. Whilst this is an effective treatment, the extent of pain reduction varies from person to person.

What types of cortisone injections are there?

Radiologists at St Vincent’s Clinic Medical Imaging & Nuclear Medicine perform the following pain blocking injections:

  • Spinal Injections
    • Facet Joint injections – injection into joints of the spine.
    • Peri neural injections (foraminal block) – injections along nerve roots of the spine.
    • Epidural injections – anti inflammatory injection into the space outside the spinal cord.
  • Non spinal joint injections
    • Anti–inflammatory injections can be performed in many joints including hands, feet, ankles, knees, hips and shoulders.

Spinal injections require precision and so radiologists use low dose CT to guide the needle placement. Joint injections are guided using ultrasound, CT or fluoroscopy as deemed appropriate.

What do I need to do before my injection and how do I prepare for the test?

  • If you take anti coagulants or “blood thinners” you may need to stop this medication before the test. Please discuss this with your referring doctor and advise our booking staff of the situation.
  • If you have any drug allergies, or if there is any chance you are pregnant,please inform a member of staff before your test.
  • You may need to bring someone with you to the test or at least have someone to escort you home. Do not drive yourself from your appointment. Please check with booking staff for specific instructions.
  • Bring all imaging previously done of the area being treated to your appointment
  • For all interventional examinations safety, medical history and consent forms will be required to be completed prior to the commencement of the examination.A radiographer or department nurse will go through these documents with you and assist with any questions you may have at the time of your appointment.

What will happen during the procedure?

The procedure should take around 10-15 minutes to perform, and is done under aseptic conditions (your skin is sterilised, and sterile equipment and gloves are used). You may experience some discomfort for a short period of time during the procedure. There is usually administration of local anaesthetic to numb the area.  This stings initially for 10-20 seconds before numbing the tissues.  Thereafter, the imaging helps to guide the needle into the intended target and cortisone is injected.  Usually the injections are well tolerated.

What happens after the test?

The post-procedural care will vary depending on the region of the body and the type of injection performed. In some cases you will need to remain in the medical imaging department for a short time after your appointment.

In the case of spinal injections, temporary weakness or altered sensation of the leg may be felt. This is due to the effects of the local anaesthetic and should only last up to 2 hours. For this reason we recommend you DO NOT drive yourself home and have someone with you to accompany you home.

Following all cortisone injections, it is advised not to do any vigorous activity for approximately 7 days, although normal day to day activities are acceptable.  Onset of symptom relief is usually not immediate, and can take several days to even weeks to settle symptoms.

Information about post- procedural care will be provided to you before you leave.

Are there any side effects?

Side effects are uncommon, with infection rates in the order of 1 in 100,000 injections.  Utmost care is taken to prevent infection from occurring.  Other reactions such as allergies, damage to tissues, facial flushing, bleeding, or transient insomnia are also rare.  Occasionally, cortisone may flare up symptoms for a few days before settling – in this setting, rest, ice and anti-inflammatory or analgesic medication may help.

Joint and spinal injections

Radiofrequency Ablation

What is radiofrequency ablation?

Radiofrequency Ablation is a minimally invasive day only procedure to reduce chronic pain which has not been adequately controlled by other means. Typically, it is used in facet joint related pain in the back or neck, but can be applied to other body parts.

Radio waves (not x-rays or radiation) are used to heat a small area around a needle tip placed around the small nerves responsible for the pain. This is done to deliberately interfere with their ability to transmit pain signals.

What does the procedure involve?

Multiple appointments are required for this procedure. With back or neck pain, at the initial appointment, a diagnostic test injection is performed under CT (Computed Tomography) guidance with local anaesthetic is required to confirm whether the nerves your doctor thinks clinically are responsible for your pain are the correct nerves to be targeted for the Radiofrequency Ablation. If your pain significantly reduces with this test injection, then the Radiofrequency Ablation treatment at these spots may help you.

The Radiofrequency Ablation procedure is performed under CT imaging guidance using a needle inserted through the skin, which can be placed with pinpoint accuracy to target the nerves responsible for your pain.

How should I prepare for the procedure?

Prior to the radiofrequency neurotomy procedure, you should:

  • Tell us if you have a pacemaker/defibrillator.
    • If you do, please let us know the make and model
  • Inform us of any drug allergies, or if there is any chance you may be pregnant before the test.
  • Arrange for someone to escort you home post procedure. Do not drive yourself home nor travel alone back to your home from your appointment.
  • Bring all previous imaging done of the area being treated to your appointment
  • If you take anticoagulants (blood thinners) you may have to stop this medication for the test. Please discuss this with your referring doctor and advise our booking staff of the situation.
  • For all interventional examinations, safety, medical history and consent forms will be required to be completed prior to the examination. A radiographer or department nurse will go through these documents with you and assist with any questions you may have at the time of your appointment.

What happens during the procedure?

You will be asked to lie face down on a CT scanner during the procedure. The CT takes low-dose images to ensure safe and accurate needle positioning. The staff will try to get you as comfortable as possible before commencing, as staying still during the procedure is important.

Your skin is sterilised, and a local anaesthetic will be administered which stings for a few seconds before numbing the site. When the needle is correctly positioned, a variety of tests to ensure good positioning will occur, some of which may make your muscles twitch – this is normal. Finally, long term local anaesthetic and cortisone are injected around the treated nerve in order to minimise discomfort which may arise following the treatment. Overall, the procedure tends not to be more than mild to moderately uncomfortable, and usually takes about half an hour (depending on the number of sites to be targeted).

What are the possible side effects?

Although side-effects are uncommon, the relatively more common side effects include:

  • Temporary localised numbness
  • Pain at the procedure site for a few days
  • Bleeding/bruising
  • Rarer complications include:

    • Infection
    • Allergic reactions to local anaesthetic or antiseptic
    • Inadvertent nerve damage (numbness, loss of muscle strength, loss of continence)

    What should I expect after the procedure?

    After the procedure, you will need to remain in the Medical Imaging Department until you feel well enough to go home. You may notice some soreness in the area where the needles were inserted, but this usually goes away within a few days. Refraining from strenuous activities for the next few days is advised. No other special precautions (including dietary) are necessary.

    Radiofrequency Ablation works better for some people than others. Onset of symptom relief is generally several days to weeks post procedure, with duration of relief ranging from a few months to more than a year.

    Radiofrequency Ablation


    A biopsy is a procedure where a small sample of tissue is taken by one of our specialist Radiologists and sent for testing by a Pathologist. A separate account will be issued from the pathology provider for the microscopic analysis of the tissue.
    Radiologists use imaging to guide them to the specific biopsy area of interest. The radiologist will choose the imaging modality and biopsy technique best suited to the area and type of tissue being examined.

    Biopsies are typically performed under Ultrasound or CT guidance and less frequently under mammographic or MRI guidance. The referral may be from your doctor or may be performed when the need for further assessment is indicated in other medical imaging.

    Biopsies are performed in a similar fashion to injections in that you will be asked a questionnaire and you will have a chance to talk to the doctor prior to the procedure. The skin is then prepared with antiseptic and a local anaesthetic is administered to numb the area (this takes several seconds to work, and is accompanied by a mild sting initially).

    Possible side effects included allergies, local bleeding, and damage to local tissues, all or which are uncommon. Infection as a complication is exceedingly rare.

    There are three biopsy techniques offered at St Vincent's Clinic Medical Imaging.

    Biopsy Patient Information brochure

    Fine needle aspiration biopsy

    A fine gauge needle is used to collect cells for analysis under a microscope.

    Core biopsy

    A larger needle is used where a spring loaded device collects a piece of tissue for analysis under a microscope.

    Vacuum assisted biopsy

    This technique is available for breast biopsies only. Vacuum assisted biopsy is a minimally invasive technique that uses a vacuum to draw tissue surrounding a rotating biopsy needle excising multiple samples per needle insertion. There is usually only one needle insertion. All referrals for breast biopsy are assessed for suitability for this technique.

    Breast biopsies Patient Information brochure

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