How to Set Up Your Ultrasound Machine for Abdominal Scanning - Veterinary Ultrasound Guide
- Echo Vet Solutions
- Jun 15
- 4 min read
Small‑animal abdominal ultrasound is one of the most valuable diagnostic tools in general practice. But even the most advanced machine can only perform as well as it is set up. Clear, diagnostic images depend on choosing the right probe, understanding your controls, and adjusting your settings in a logical order.
This guide walks you through how to set up your ultrasound machine for abdominal scanning, using practical, real‑world principles that improve image quality immediately.
For most abdominal examinations, a microconvex probe is the ideal choice. Its small footprint makes it easy to manoeuvre between ribs and around the costal arch, and its broad frequency range suits both dogs and cats.
A linear probe can be extremely useful for superficial structures such as abdominal wall masses, lymph nodes, or paediatric patients. However, its wider footprint can make deep abdominal imaging more awkward.
Probe Orientation: A Simple Rule That Prevents Confusion
Correct orientation ensures consistent interpretation and prevents left–right errors.
Sagittal views: marker towards the head
Transverse views: marker to the patient’s right
Dorsal/medial views: marker towards the midline
Longitudinal limbs: marker proximally
Most machines display a small marker at the top left of the image—this should always match the probe marker.
Image Optimisation: Adjust Settings in This Order
1. Time Gain Compensation (TGC)
TGC controls brightness at different depths. For abdominal scanning, a gentle “slope” works best:
Lower gain in the near field
Higher gain in the far field
This compensates for natural attenuation and prevents the top of the image from appearing washed out.
2. Depth
Set the depth so the organ of interest fills around 75% of the screen. Too shallow and you lose context; too deep and you waste resolution.
3. Focus
The focal zone marks the point of highest lateral resolution. Place it:
At the level of small structures (e.g., adrenal glands)
At the deepest part of large organs (e.g., liver, urinary bladder)
A misplaced focal zone is one of the most common causes of soft, blurry images.
4. Frequency
Higher frequency = better detail, less penetration Lower frequency = deeper penetration, less detail
Use the highest frequency that still allows you to see the entire organ. This single adjustment can dramatically improve parenchymal detail.
5. Overall Gain
Gain brightens or darkens the entire image.
Higher gain helps when imaging solid organs like the liver
Lower gain is essential for fluid‑filled structures like the bladder to avoid artefacts
Bright rooms (e.g., kennel side) often require higher gain
Aim for fluid to appear black and soft tissue to sit in a mid‑grey range.
Harmonic Imaging
Most modern machines offer harmonic imaging, which can improve contrast and reduce artefacts. Try scanning with harmonics both on and off—some patients benefit from it, others do not.
Artefacts are not always a problem—many are diagnostically useful once you know how to interpret them.
Acoustic Shadowing
Occurs when the beam hits something highly reflective (e.g., mineralisation, bone, dense foreign bodies). Useful for identifying calculi or confirming mineral content.
Acoustic Enhancement
Seen deep to fluid‑filled structures such as the gallbladder or cysts. Helps differentiate true cysts from solid nodules.
Reverberation (“dirty shadowing”)
Associated with gas. Helpful for identifying gastrointestinal gas or free abdominal gas.
Side‑Lobe & Slice‑Thickness Artefacts
Appear as false echoes within fluid, often mistaken for bladder sludge. True sludge moves; artefact does not.
Practical Tips for Everyday Scanning
Reset TGC when switching between organs
Use plenty of gel and clip fur generously
Keep the probe perpendicular to the skin to avoid beam‑angle distortion
Always scan abnormalities in at least two planes
If the image looks wrong, return to your preset and start again
Final Thoughts
Setting up your ultrasound machine correctly is one of the fastest ways to improve diagnostic confidence. By following a consistent optimisation sequence—TGC → Depth → Focus → Frequency → Gain—you’ll produce clearer, more reliable images across all patients.
Want to Build Your Confidence in Abdominal Ultrasound?
At Echo Vet Solutions, we offer bespoke in-practice ultrasound and echocardiography training delivered at your own practice, on your own patients, using your own equipment. Our training is hands-on from the outset and is tailored to your current experience level and the case mix you see in practice.
Our instructors hold advanced qualifications in small animal imaging, bringing the kind of clinical depth that translates directly into better scanning in day-to-day practice.
References and Further Reading
Forrest LJ et al. (2003). Tissue harmonic ultrasound for imaging normal abdominal organs in dogs and cats. Veterinary Radiology & Ultrasound, 44(3), 330–334. PubMed
Ziegler LE et al. (2002). Harmonic ultrasound: A review. Veterinary Radiology & Ultrasound, 43(6), 501–509. Wiley Online Library
Berry CR, Mauragis D. (2015). Small Animal Abdominal Ultrasonography, Part 3: Basics of Imaging Optimization. Today's Veterinary Practice. Read article
Mattoon J, Nyland T. (2014). Small Animal Abdominal Ultrasound, 3rd ed. Philadelphia: Saunders-Elsevier.
Penninck D, d'Anjou M. (2015). Atlas of Small Animal Abdominal Ultrasound, 2nd ed. Ames, IA: Wiley Blackwell.
