How to Order and Interpret Prostate Ultrasound
Order transabdominal ultrasound when a patient has selected minimally invasive or surgical intervention for BPH, requesting measurement of prostate volume, post-void residual (PVR), intravesical prostatic protrusion (IPP) grade, and identification of intravesical lobes. 1
When Ultrasound Is NOT Indicated
Do not order prostate ultrasound for:
- Initial evaluation before starting watchful waiting 1
- Before initiating medical therapy with alpha-blockers or 5-alpha reductase inhibitors 2, 1
- Determining "need for treatment"—symptoms and patient bother drive this decision, not anatomy 1
When Ultrasound IS Indicated
Order transabdominal or transrectal ultrasound when:
- Patient has selected surgical or minimally invasive intervention (TURP, laser therapy, etc.) 1
- Determining candidacy for specific surgical procedures 1
- Assessing for intravesical lobes that impact surgical approach 1
- Staging prostate cancer (rectal ultrasound to assess capsular and seminal vesicle involvement) 2
Essential Measurements to Request
When ordering ultrasound for BPH evaluation, specifically request:
- Prostate volume (measured in cubic centimeters or grams) 1
- Post-void residual (PVR) volume 1
- Intravesical prostatic protrusion (IPP) grade 1
- Presence of intravesical lobes (middle lobe protruding into bladder) 1
- Anatomical features that may impact therapy choice 1
Interpreting Results
Prostate Volume
- Prostate size alone does not determine treatment need—a man with large prostate but minimal symptoms may not require intervention, while someone with moderate enlargement but severe bother may benefit from treatment 1
- Larger prostates (>40g) predict better response to 5-alpha reductase inhibitors like finasteride 3
Post-Void Residual (PVR)
- Large PVR volumes (e.g., 350 mL) may indicate bladder dysfunction and predict slightly less favorable treatment response 1
- PVR is NOT a contraindication to watchful waiting or medical therapy—many patients maintain large residual volumes without urinary tract infection, renal insufficiency, or bothersome symptoms 1
- Do not withhold treatment based solely on elevated PVR 1
Intravesical Prostatic Protrusion (IPP)
- IPP grading combined with prostate volume and PVR provides anatomical staging of BPH 1
- Higher IPP grades may predict need for surgical intervention over medical management 1
Common Pitfalls to Avoid
- Do not order ultrasound before starting alpha-blockers—symptom response to tamsulosin is not dependent on baseline prostate size 1
- Do not use ultrasound findings alone to determine treatment—patient symptoms and bother are primary determinants 2, 1
- Transabdominal ultrasound is preferred over cystoscopy for anatomical assessment when surgery is considered 4
Alternative to Ultrasound for Cancer Evaluation
For differentiating BPH from prostate cancer: