Best ultrasound settings for feline abdominal scans

Optimizing ultrasound settings is critical when performing abdominal scans on feline patients. Cats present unique challenges due to their small body size, rapid respiratory rates, and lower tolerance for restraint compared to dogs. High-quality imaging requires not just patience, but precise adjustments to maximize resolution while maintaining adequate penetration. Without specific optimization, crucial details in the feline liver, kidneys, or intestinal wall can be lost to artifacts or poor contrast.

This guide covers the essential technical parameters needed to achieve diagnostic clarity, including probe selection, frequency adjustments, and Doppler settings tailored for feline anatomy. By mastering these controls, veterinarians can reduce scan time and improve diagnostic confidence. For comprehensive feline ultrasound solutions, selecting the right machine and settings is the first step toward superior patient care.

Quick settings cheat sheet

Use this reference table as a starting point for a standard 4-5 kg cat. Adjustments may be necessary based on the specific body condition score (BCS) and pathology.

How to optimize feline abdominal ultrasound settings

Probe selection and Frequency

For most feline abdominal scans, a high-frequency microconvex probe (5.0–8.0 MHz) is the workhorse. Its small footprint fits easily between ribs and into the subcostal space. However, for superficial structures like the intestinal wall or the spleen, a linear probe (10.0–14.0 MHz) offers superior spatial resolution. Always start with the highest frequency possible to maximize detail, only lowering it if penetration is insufficient to reach the dorsal abdomen.

Depth and Focus optimization

A common error is leaving the depth set too deep, resulting in a tiny image surrounded by wasted space. Decrease depth until the organ of interest occupies roughly 75% of the screen. Simultaneously, adjust the focal zone to align with the specific structure being imaged. For kidneys, place the focus at the level of the renal pelvis. Correct focus placement ensures the ultrasound beam is narrowest—and resolution highest—exactly where you need it.

Gain, TGC, and Dynamic Range

Total Gain amplifies the entire return signal. If the image is too dark, increase gain; if “snowy” or washed out, decrease it. Time Gain Compensation (TGC) sliders allow you to adjust brightness at specific depths. In cats, ensure the near field isn’t too bright (which obscures superficial masses) and the far field is visible. Dynamic Range (DR) controls the contrast. A higher DR (60-70 dB) creates a smoother image with more shades of gray, ideal for subtle parenchymal changes in the liver or spleen. Lower DR increases contrast, making edges sharper but texture coarser.

Frame Rate and Doppler

Cats often pant or wiggle, causing motion blur. Maintain a high frame rate by narrowing the sector width (field of view) to just the area of interest and using a single focal zone. When using Color Doppler to assess renal perfusion or hepatic vessels, adjust the Pulse Repetition Frequency (PRF) to detect low-velocity flow (scale 10-20 cm/s) and increase the wall filter slightly to remove motion artifacts from breathing.

Step-by-step feline abdominal scanning protocol

Consistency is key. A standardized protocol ensures no organ is missed. Begin with a calm environment, proper chemical restraint if necessary, and a focused patient preparation: shave from xiphoid to pubis and apply alcohol followed by acoustic gel. Wait 2 minutes for optimal contact.

Liver: Start at the xiphoid process in the subcostal view. Fan progressively from left to right. Assess echogenicity relative to the falciform fat (liver should be isoechoic or slightly hyperechoic).

Gallbladder: Locate to the right of the midline. Check for sludge (common in older cats) or wall thickening. Ensure the “kiwi-like” appearance is clear.

Stomach: Slide caudally to the stomach. Evaluate wall layering (rugal folds) and motility. Gas is a common barrier here; minimal pressure helps displace it.

Spleen: Move to the left cranial abdomen. The feline spleen is small and superficial. Look for the “triangle” head and smooth tail. Use a linear probe here if available.

Kidneys: Scan the left kidney first (easier to find), then the right. Measure length in a true sagittal plane. Compare cortical echogenicity to the spleen (left) or liver (right).

Intestines: Follow the loops systematically throughout the mid-abdomen. Measure wall thickness and look for loss of layering, which may indicate lymphoma or IBD.

Bladder: Finish at the caudal abdomen. Evaluate the wall thickness and check the lumen for calculi or sediment. A full bladder acts as a helpful acoustic window.

Troubleshooting: artifacts and quick fixes

Small patients are prone to specific artifacts. Use this guide to resolve common image quality issues.

Choosing the right equipment

Achieving the best images requires hardware capable of handling the high frequencies cats require. When looking for the best portable ultrasound machines for vets, prioritize systems that offer specific veterinary presets and high-resolution imaging chains. Lightweight, portable units are ideal for moving between exam rooms or making house calls.

Additionally, the quality of your veterinary ultrasound probes is paramount. A dedicated high-frequency microconvex probe is standard, but adding a linear probe can significantly enhance gastrointestinal diagnostics. For vascular assessment, ensuring your system has sensitive color doppler veterinary ultrasound capabilities allows for precise evaluation of blood flow in small vessels, which is critical for diagnosing portosystemic shunts or renal perfusion issues in feline patients.

Conclusion & resources

Mastering feline abdominal ultrasound is a blend of correct technique and optimized settings. By systematically adjusting depth, focus, and frequency, and adhering to a consistent scanning protocol, you can visualize the subtle details necessary for accurate diagnosis. We encourage continuous learning to stay sharp with your imaging skills.

Explore our full range of veterinary imaging solutions or contact us for personalized advice. For further training, visit the Dawei Veterinary Medical or reach out via our Contact Us page to find the perfect equipment for your practice.