Interpreting Penile Doppler Reports

1. How the Study Is Performed

• PSV — Peak Systolic Velocity (cm/s)
• EDV — End-Diastolic Velocity (cm/s)
• RI — Resistive Index = (PSV − EDV) / PSV
• Cavernous artery diameter (baseline vs. post-injection)
• Acceleration time — the systolic rise time

2. Key Parameters & Normal Values

A normal erection in a healthy young man: PSV ~89 cm/s, EDV = 0 cm/s, RI = 1.0 (as shown in the image below)

3. Waveform Pattern During Normal Erection Progression

4. Diagnostic Interpretation

Arteriogenic ED (Arterial Insufficiency)

• PSV < 25 cm/s — diagnostic of cavernous arterial insufficiency
• PSV 25–35 cm/s — borderline; ~20% of these patients may still have normal CIS test (false-positive zone)
• Acceleration time > 122 ms — additional marker of poor arterial inflow
• Artery diameter increase < 75% after ICI — supportive finding
• Asymmetry: A difference of > 10 cm/s between the two cavernous arteries suggests a unilateral atherosclerotic lesion; flow reversal across a collateral vessel may indicate the same

Venogenic ED (Cavernous Veno-Occlusive Dysfunction)

• EDV > 5 cm/s at 15–20 min post-ICI (when PSV is adequate, i.e., ≥ 25–30 cm/s)
• RI < 0.75 — indicates failure of veno-occlusive mechanism
• Rapid detumescence despite high PSV
• The key point: EDV should only be interpreted as abnormal when arterial inflow is confirmed adequate (PSV ≥ 35 cm/s); if PSV is low, high EDV may simply reflect poor arterial drive rather than true venous leak

Normal Vascular Function

• PSV ≥ 35 cm/s, EDV = 0 cm/s (or negative), RI ≥ 0.80 → suggests psychogenic or neurogenic ED

Mixed Vasculogenic ED

• Low PSV and elevated EDV → combined arterial and venous pathology

5. Special Findings

6. Technical Pitfalls

• Anatomic variants: Early branching or multiple cavernous arteries can falsely lower measured PSV. Perforators from dorsal or spongiosal arteries can alter velocity measurements.
• Measurement location matters: PSV varies between crus, proximal, and mid-cavernosal positions.
• Patient anxiety: Can suppress the erectile response, giving falsely low PSV — always re-dose before concluding arteriogenic ED.
• Inadequate pharmacostimulation: A subtherapeutic ICI dose is the most common cause of false arteriogenic diagnosis. Re-dose if erection quality is poor.
• EDV interpretation only valid when PSV is adequate: Don't label venous leak if PSV is low.

7. Summary Decision Tree

Post-ICI Penile Doppler
        │
        ▼
   PSV < 25 cm/s ──────────────► Arteriogenic ED
        │
   PSV 25–35 cm/s ─────────────► Borderline / repeat or re-dose
        │
   PSV ≥ 35 cm/s
        │
        ├── EDV < 5 cm/s, RI ≥ 0.80 ──► Normal vascular; consider psychogenic/neurogenic
        │
        └── EDV ≥ 5 cm/s, RI < 0.75 ──► Venogenic ED (cavernous veno-occlusive dysfunction)

• Campbell-Walsh-Wein Urology, Chapter 69: Duplex Ultrasonography (Gray Scale or Color-Coded), pp. 2019–2020
• Smith & Tanagho's General Urology, 19th ed., p. 627 (Color Duplex Ultrasonography section)