RadteraUltrasound Paracentesis Marking / Guidance
USNo contrastAbdomen & Pelvisverify
Indications
- Symptomatic ascites requiring drainage
- Diagnostic paracentesis (suspected SBP / new ascites)
- Site marking or real-time guidance for safe needle placement
Patient prep
- None specific; have patient void before procedure
- Supine or slightly lateral decubitus toward side of intended tap
Contrast
None / non-contrast
Technique
- Curvilinear 2-5 MHz transducer (linear to assess abdominal wall vessels)
- Survey for largest, safest fluid pocket (commonly LLQ) away from bowel/organs
- Use color Doppler to identify and avoid abdominal wall vessels (e.g., inferior epigastric)
- Mark skin site and document depth, or perform real-time ultrasound-guided puncture with sterile technique
Series / Sequences
| # | Series / Sequence | Plane | Notes |
|---|---|---|---|
| 1 | Survey of ascites - all quadrants | As needed | Locate largest fluid pocket; estimate depth |
| 2 | Chosen site image | Two planes | Pocket size, depth from skin, no intervening bowel/organ |
| 3 | Color Doppler of abdominal wall at site | As needed | Avoid inferior epigastric and other wall vessels |
Key points
- Select largest fluid pocket free of bowel; measure depth from skin and document at the marked site
- Use color Doppler to avoid abdominal wall vessels
- Real-time guidance preferred for small/loculated collections; marking suffices for large free ascites if position unchanged
- Maintain sterile technique for ultrasound-guided procedures
References
• AIUM Practice Parameter for the Use of Ultrasound to Guide Vascular Access / Interventional Procedures
• ACR-AIUM-SRU Practice Parameter for the Performance of Ultrasound-Guided Interventional Procedures
• Radiopaedia: Ultrasound-guided paracentesis link
• ACR-AIUM-SRU Practice Parameter for the Performance of Ultrasound-Guided Interventional Procedures
• Radiopaedia: Ultrasound-guided paracentesis link
Source: Researched — verify against your institution
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Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.