What is Computer-Guided Transperineal Prostate Biopsy?
Physicians may use ultrasound- and MRI-guided biopsy to obtain tissue samples from the prostate gland. However, physicians most often perform prostate biopsies using ultrasound guidance where your physician places a special biopsy needle into the prostate gland through the wall of the rectum to extract several small samples of prostate tissue for laboratory analysis. This is called transrectal ultrasound (TRUS) guided biopsy.
Computer-guided transperineal prostate biopsy is a technique in which your physician accesses the prostate gland through the perineum (transperineal) to collect tissue samples from the prostate gland with the help of computer guidance and examine the samples in a laboratory setting to determine whether or not cancer is present.
Your physician can also utilize magnetic resonance imaging (MRI) or Mp-MRI (multiparametric MRI). MRI and Mp-MRI offer more detailed images of the prostate than ultrasound can. Mp-MRI is an advanced imaging technique that combines 3 MRI methods to give information on the function and structure of the prostate.
Prior to the biopsy, your physician will inspect the MRI images with the assistance of computer-aided detection (CAD) software. This will pinpoint specific regions that may need further examination. The physician may perform MRI-guided in-bore biopsy utilizing either a transrectal or transperineal method. Both approaches typically use computer software to guide the needle to the proper position within the prostate.
Indications for Computer-Guided Transperineal Prostate Biopsy
Your physician may recommend a computer-guided transperineal approach for prostate biopsy for the following:
- If the cancer is noted to be at the anterior portion of the prostate gland and too far away from the rectum for TRUS
- If transrectal ultrasound is not possible due to previous rectal surgery
- Your physician deems this is the best approach for biopsy
- For some mapping biopsies
Preparation for Computer-Guided Transperineal Prostate Biopsy
Pre-procedure preparation for computer-guided transperineal prostate biopsy may involve the following steps:
- You will be asked if you have allergies to medications, anesthesia, or latex.
- You should inform your doctor of any medications or dietary supplements that you are taking or any conditions you have such as heart or lung disease or any recent illnesses.
- You may be asked to stop medications such as blood thinners for a week or two prior to the procedure as this will help prevent excessive bleeding during and after the biopsy.
- You may be given oral antibiotics a day prior to and morning of the biopsy to help prevent infection.
- If you are having an MRI-guided biopsy, you will need to wear metal-free clothing and remove any metallic objects, such as jewelry, hearing aids, and watches.
- You are advised to eat light meals on the day prior to and the day of your biopsy. This will help make it easier to insert the ultrasound probe or endorectal coil (MRI procedure).
- You are advised to arrange for someone to drive you home after the procedure as you may receive sedation during the procedure.
- A signed informed consent form will be obtained from you after the pros and cons of the biopsy procedure have been explained.
Procedure for Computer-Guided Transperineal Prostate Biopsy
The computer-guided transperineal biopsy procedure consists of a traditional MRI unit - a large cylinder-shaped tube surrounded by a circular magnet. In most MRI units, the magnetic field is produced by passing an electric current through wire coils. Other coils are inside the machine and, in some cases, are placed around the area of the prostate being imaged. These coils send and receive radio waves, producing signals that are detected by the machine. A computer processes the signals and creates a series of images, each of which shows a thin slice of the prostate. The radiologist can study these images from different angles. MRI is typically able to pinpoint the difference between normal and diseased tissue better than X-ray, CT, and ultrasound. The MRI-guided procedure may use contrast material. During the procedure, you will be asked to lie down on your back on a table that slides into the tunnel towards the center of the magnet. You may receive antibiotics, sedatives, or light general anesthetics to keep you comfortable and relaxed during the biopsy. If you have the procedure under local anesthetic, your doctor will administer an anesthetic into the perineum (between the anus and scrotum) to numb the area. Using computer/MRI-guided images, your physician will advance the biopsy needle into the prostate through the perineum and a number of samples are obtained for microscopic examination in the laboratory. Sometimes doctors use a template (or grid) with lots of holes over your perineum and guide the needle through the template. They then take between 30 to 50 samples. This is called a transperineal template biopsy. The whole procedure takes about 30 to 45 minutes.
Post-Procedure Care and Recovery
In general, post-procedure care instructions and recovery after computer-guided transperineal prostate biopsy will involve the following steps:
- You will be transferred to the recovery area where your nurse will closely observe you for any allergic/anesthetic reactions and monitor your vital signs as you recover.
- It is important to drink plenty of fluids for the first 24 hours post procedure.
- You may experience pain, inflammation, and discomfort around the treatment area. Pain and anti-inflammatory medications are provided as needed.
- You will also be prescribed antibiotics to prevent the risk of infection.
- You may notice small amounts of blood in your urine, stools, or semen that should resolve in a few weeks.
- You will likely be discharged on the same day or the following day after the procedure.
- You should be back to your normal routine in a few days with certain activity restrictions. You will need to resume your activity level gradually.
- You should not drive home if you have had a general anesthetic as it takes some time to fully recover from the effects of anesthesia.
- Follow-up appointments will be scheduled to monitor your progress.
Risks and Complications
Computer-guided transperineal prostate biopsy is a safe procedure; however, as with any procedure, there are risks and complications that can occur, such as:
- Internal bleeding
- Difficulty passing urine
- Blood in the semen, urine, or feces
- Allergic/anesthetic reactions