An ultrasound of the prostate is a diagnostic imaging procedure that uses high-frequency sound waves to create real-time pictures of the prostate gland and surrounding structures. This technique, most commonly performed as a transrectal ultrasound (TRUS), provides detailed visualization of the gland’s size, shape, and internal texture. It is used to evaluate prostate health, often following an abnormal digital rectal exam or an elevated level of prostate-specific antigen (PSA). The images help providers detect conditions such as benign prostatic hyperplasia (BPH), inflammation, or suspicious areas that may indicate cancer. The procedure can also guide necessary follow-up actions, such as targeted tissue sampling.
Patient Preparation Before the Exam
Proper patient preparation focuses mainly on clearing the lower bowel. Patients are typically instructed to perform a cleansing enema, such as a Fleet enema, one to four hours before the scheduled appointment. This step is important because the presence of stool or gas in the rectum can interfere with sound waves and obstruct the clear view of the prostate gland.
Patients should wear comfortable, loose-fitting clothing to allow for easy changing into a gown. If the ultrasound includes a prostate biopsy, a course of prophylactic antibiotics, often starting the night before, will be prescribed to minimize infection risk. Common antibiotics used include Ciprofloxacin (Cipro).
For a planned biopsy, patients must temporarily stop certain medications that affect blood clotting. Blood thinners, including prescription anticoagulants and over-the-counter NSAIDs like aspirin or ibuprofen, must generally be stopped seven to ten days prior. This precaution helps prevent excessive bleeding during tissue sampling, and the specific timing should always be discussed with the prescribing physician.
Patients are usually asked to empty their bladder just before the procedure. While a full bladder is sometimes required for other pelvic ultrasounds, emptying the bladder for TRUS ensures optimal patient comfort and better positioning. Following these instructions helps capture clear and accurate images of the prostate.
Step-by-Step Transrectal Ultrasound (TRUS)
Upon entering the examination room, the patient changes into a gown and lies on the examination table. The most common position is lying on the left side with the knees bent toward the chest, often called the fetal position. This positioning allows the physician easiest access and provides a relaxed posture for the patient.
The imaging device is a specialized transducer probe, typically the size of an index finger. The probe is covered with a disposable sheath and coated with a sterile, water-based gel for smooth insertion. If a biopsy is scheduled, the prostate tissue may be numbed with a local anesthetic injection before probe insertion.
The lubricated probe is gently guided into the rectum, which may cause a sensation of pressure or fullness. Since the prostate sits directly in front of the rectum, the transducer is placed in close proximity for high-resolution imaging. The physician slowly adjusts and rotates the probe to visualize the entire gland from various angles.
As the probe transmits sound waves, a computer translates the returning echoes into a live image on a monitor. The physician systematically measures the prostate’s dimensions to calculate its volume and assess for symmetry or abnormal growths. The procedure may also incorporate Doppler technology to evaluate blood flow, helping identify areas of concern.
The active scanning time for a TRUS alone is brief, often lasting only 5 to 15 minutes. If a biopsy is performed, the total procedure duration may extend to 15 to 30 minutes.
After the Procedure and Next Steps
Once the images and measurements are captured, the ultrasound probe is carefully withdrawn, and the patient is assisted in cleaning any remaining gel. Following a TRUS without a biopsy, there are typically no restrictions, and the patient can immediately return to normal activities. If the procedure included a biopsy, mild discomfort or soreness in the rectal area and at the base of the penis is common for a few days.
Patients who underwent a biopsy must limit strenuous activity for 24 to 48 hours to minimize bleeding risk. Small amounts of blood in the urine, stool, and semen following a biopsy are common and can persist for several days or weeks. Increasing fluid intake for the next couple of days is recommended to help flush the urinary system and reduce clot formation.
The tissue samples collected during a biopsy are sent to a pathology laboratory for analysis, while a radiologist or urologist reviews the ultrasound images. The final results, which may take several days, are communicated during a follow-up consultation with the referring physician. During this consultation, the physician explains the findings, discusses any detected conditions, and outlines the next steps, such as a treatment plan or further testing.