CT Guided Thoracentesis

What is a Thoracentesis?

A thoracentesis is a procedure in which the Radiologist (x-ray doctor) inserts a needle into the pleural space (lung field in the chest) to drain fluid off the lung. CT scan images are taken to visualize the fluid.


You will be lying on the CT scan table during this procedure. The Radiologist will insert a needle/catheter into the pleural space to drain off the fluid. You may have the urge to cough, as the fluid is being withdrawn. This is normal. The needle will be removed when the exam is completed. A chest x-ray will be taken after the thoracentesis.

Procedure time: 60 - 90 minutes.

Patient Preparation Instructions:

  1. You may be required to have blood work prior to your procedure. Radiology will call you prior to your exam. Outpatient registration will have a copy of your lab work order, if needed.
  2. Do not eat or drink 2 hours prior to your test.
  3. You will need someone available to drive you home, only if it becomes necessary.
  4. You can take your normal medications with a small amount of water unless you are on:
    • Aspirin – Stop 3-5 days before exam.
    • Coumadin, Plavix – Stop 3-5 days before exam.
    • Blood Thinners (other) – Stop 3-5 days before exam.
  5. You may be asked to stay for up to 2 hours of observation following your test before being discharged. You will be given instructions prior to leaving.

For Your Information:

  1. After registration you will go to an observation area prior to your exam. You will be asked to change into a hospital gown and assessed prior to going to the Radiology Department. You will be taken back to this area following your exam for follow-up assessment.
  2. An IV may be started in your hand or arm, only if the radiologist requests it.
  3. Relax and follow instructions given to you by the CT scan staff.
  4. The Radiologist will give the results to your doctor. Your doctor will share the results with you; feel free to ask your doctor any questions.
  5. If you have any questions regarding this test, please call 419-394-3335 ext. 3550 for assistance.

Grand Lake Health System
200 St. Clair Street, St. Marys,
Ohio 45885-2400
| 1-419-394-3335 | 1-877-564-6897