Prostate or rectal sonography is helpful in the detection of prostate cancer in patients with an elevated prostate specific antigen (PSA) titer. This study can also be used to stage and monitor rectal cancer and to detect other perirectal diseases.
Rectal ultrasound of the prostate is a valuable tool in the early diagnosis of prostate cancer. When combined with rectal digital examination and PSA testing, very small prostate cancers can be identified. Rectal prostate sonography is also helpful in evaluating the seminal vessels and other perirectal tissue. Ultrasound is helpful in guiding prostate biopsy, and can be helpful in quantifying the volume of prostate cancer. When radiation therapy implantation is required for treatment, ultrasound is used to map the exact location of the prostate cancer. Rectal ultrasound is helpful in staging rectal cancers as well. The depth of transmural involvement and presence of extrarectal extension can be accurately assessed.
Real-time ultrasonography requires the emission of high-frequency sound waves from a special transducer placed in the rectum. The sound waves are reflected back to the transducer and electronically converted into a pictorial image. This test can be performed in the ultrasound section of the radiology department and is now being routinely performed in most urologists’ offices. Results are available almost immediately.
Rectal Sonography cannot be performed on patients with latex allergy, because rectal ultrasound requires placement of the probe in a latex sac.
How is Prostate Sonography Performed?
- The patient is required to have a small volume of enema an hour before the test.
- The patient is placed in the left lateral decubitus position.
- A digital rectal examination may be performed to assess the prostate gland or rectal tumor.
- A draped and lubricated ultrasound probe is placed within the rectum.
- Scans are obtained in various spatial planes.
Findings of Rectal Sonography
By using Rectal or Prostate Sonography, the following conditions may be diagnosed:
An enlarged solid prostate mass anterior to the rectum is suggestive of prostate disease. This can be an indication of Prostate Cancer or Benign Prostatic Hypertrophy.
Prostatitis: An enlarged bulgy echogenic gland indicates inflammation.
Seminal vesicle tumor: An echogenic mass in the region of the seminal vesicle may indicate tumor.
A hypoechoic fluid-filled mass that is well circumscribed indicates abscess, especially if surrounded by a phlegmonous reaction. This can be a result of Prostate Abscess or Perirectal abscess.
Intrarectal or Perirectal tumor: Extent of tumor can be accurately assessed with ultrasound. Lymph node metastasis, if present, is evident.