CT Guided Drainage

CT Guided DrainAll outpatients that have been referred for a CT Guided Drainage will receive copies of our CT drainage information leaflet when they receive their appointment letter. These may also be found at the bottom of this page or in the PILS link on the front page.

What is a CT guided drainage?

An abscess is a collection of pus that has built up within the tissue of the body. The main symptoms and signs of an internal abscess include pain in the affected area, a high temperature, and generally feeling unwell. Internal abscesses rarely heal themselves, so prompt medical attention is indicated if such an abscess is suspected.

In the past, drainage of an abscess/ collection inside your chest or abdomen would have required an open operation.

Now it is possible to drain collections by inserting a plastic tube(s) called a drainage catheter, into the abscess/collection through the skin, with only a tiny incision.

This procedure is called percutaneous (through the skin) abscess drainage.

Before the scan

You will be referred for this test by one of the clinicians in the hospital; they will send a request to the CT bookings clerk who will send out an appointment for you. There may be scope to change this appointment time if it does not suit you.


Please ring the radiology department if you:

  • Take warfarin, aspirin and Clopidogrel or anything that thins your blood.
  • Are diabetic.

You need to be an inpatient in the hospital.

Your doctors will need to have taken blood for clotting, platelets and renal function and the results must be available prior to the procedure.

You will be routinely screened for MRSA (Methicillin-resistant Staphylococcus aureus) prior to the planned procedure.

You will be asked not to eat for four hours but can drink water up to one hour prior to the procedure, unless otherwise advised.

You will be asked to put on a hospital gown and a cannula will be placed in a vein usually on the back of the hand.

If you have any allergies, you must inform the staff looking after you. If you have previously reacted to intravenous contrast medium (the dye used for kidney x-rays and CT scans) then you must tell the radiographers.

What actually happens during a percutaneous abscess/collection drainage?

Before being taken into the scanning room the Radiologist who is performing the procedure will ask you for your consent. If you have any questions regarding your procedure, now is a good time to ask.

You will be asked to lie on the CT scanning table, in the position that the radiologist has determined is more suitable.

If you have not already a cannula placed in the back of your hand or arm, then one may be inserted at this point.

The radiologist will use the CT scan images to decide on the most suitable point for inserting the drainage catheter.

The Radiographers will accurately mark this point with an indelible pen using the centring lights on the scanner to guide them.

The Radiologist will keep everything as sterile as possible, and may wear a theatre gown and operating gloves. Your skin will be cleaned with antiseptic, and you may be covered with a sterile drape.

Your skin will then be anaesthetised, and the biopsy needle inserted into the collection.

What happens next will vary in different situations. Any pus may simply be drained through the needle (aspirated), or a slightly larger needle or plastic tube, which is then withdrawn altogether. Alternatively, it may be necessary to place a larger drainage tube (catheter) into the collection and attach it to the skin, with a special dressing, so that the pus can continue to drain for several days.

While the first part of the procedure may seem to take a while, actually performing the percutaneous drainage does not take very long at all, using the CT scans to accurately guide the needle/ catheter into position. You must keep as still as possible during this stage, if it becomes too uncomfortable please let us know.

Will it hurt?

Most percutaneous drain insertions are uncomfortable for a short period of time. When the local anaesthetic is injected, it will sting to start with, but this soon passes off, and the skin and deeper tissues will soon feel numb. Later, you may be aware of the needle, or the wire and catheter, passing into the collection(s) and sometimes this is painful.

There will be a nurse and radiographer looking after and monitoring you throughout the procedure.


How long will it take?

Every patient’s situation is different, and it is not always easy to predict how complex or how straight forward the procedure will be. It may be over in twenty minutes, depending on the complexity and number of percutaneous drains to be inserted.

What happens afterwards?

You will be taken back to your ward on a trolley accompanied by a nurse.

Nurses on the ward will continue to carry out observations, such as your heart rate and blood pressure to make sure there are no problems for several hours post procedure. You will generally stay in bed for a few hours, until you have recovered.

If the drainage catheter has been left in your body for the time being, then it will be attached to a collection bag. It is important that you try and take care of this. You should try not to make any sudden movements, for example getting out of a chair, without remembering the bag, and making sure that it can move freely with you. It may need to be emptied occasionally, and the catheter may require flushing with a saline solution.

How long will the catheter stay in, and what happens next?

These are questions which only the doctors looking after you can answer.

It may only need to stay in a short time. It is possible that you will need further scans to check that the collection has been drained satisfactorily.

You will be able to lead a normal life with the catheter in place, and when the catheter is removed, generally there is only slight discomfort.

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