Transrectal Ultrasound (TRUS) for Prostate Examination
Transrectal ultrasound (TRUS) is the recommended ultrasound technique for examining the prostate, particularly when performing prostate biopsies. 1
Role of TRUS in Prostate Evaluation
TRUS serves several important functions in prostate evaluation:
- Primary biopsy guidance: TRUS-guided biopsy is the standard method for obtaining prostate tissue samples when cancer is suspected 1
- Visualization: Allows visualization of the internal anatomy of the prostate, though with limited specificity for cancer detection alone 2
- Measurement: Enables assessment of prostate size and volume
TRUS-Guided Biopsy Technique
When performing TRUS-guided prostate biopsies:
- A minimum of 8 cores should be obtained (range 6-12) 1
- The procedure should be performed under local anesthesia 3
- Antibiotic prophylaxis is essential to prevent infection 3
- The biopsy needle is directed to systematic locations throughout the prostate 2
Indications for TRUS-Guided Biopsy
TRUS-guided biopsy is indicated in patients with:
- Abnormal digital rectal examination (DRE) findings 1
- Elevated serum PSA levels 1
- Prior negative biopsy but persistent suspicion of prostate cancer 1
Limitations of TRUS
It's important to recognize that TRUS has limitations:
- Low specificity for cancer detection when used alone 2
- Hypoechoic lesions may represent cancer but have considerable overlap with benign conditions 2
- Systematic biopsies may miss some clinically significant cancers 4
Advanced Ultrasound Techniques
Recent advances in ultrasound technology have improved TRUS capabilities:
- MRI-TRUS fusion: Combines MRI imaging with real-time ultrasound guidance for targeted biopsies 5
- Contrast-enhanced TRUS: May improve visualization of suspicious areas 2
- Elastography: Evaluates tissue stiffness which may correlate with cancer 2
Role of MRI with TRUS
According to current guidelines, MRI has an increasingly important role:
- MRI before TRUS-guided biopsy can identify suspicious lesions for targeted sampling 1
- For patients with prior negative biopsies, MRI followed by MRI-targeted biopsies is recommended (rated 8/9 for appropriateness) 1
- For patients on active surveillance, MRI with TRUS-guided biopsy is recommended (rated 8/9 for appropriateness) 1
Patient Acceptance and Complications
- Most patients (95%) report only minor or no discomfort during TRUS examination 3
- When combined with biopsy, 92% still report minor or no discomfort 3
- Infection is a potential complication (4.1% overall rate), but proper antibiotic prophylaxis can reduce this risk 3
- Patients generally prefer TRUS-guided biopsy over finger-guided fine needle aspiration 3
TRUS remains the standard ultrasound approach for prostate evaluation and biopsy guidance, though its diagnostic value is enhanced when combined with other modalities, particularly MRI for targeted biopsies in appropriate clinical scenarios.