# Abdominal Ultrasound in Cats: Normal Findings and Common Abnormalities


## Key Takeaways

- Feline abdominal ultrasound requires higher frequency transducers (8-14 MHz) and specific patient positioning (dorsal recumbency with forelimbs pulled caudally) for optimal visualization of organs like the pancreas and biliary tree, with 8-12 hour food withholding crucial to reduce gastric gas.
- Normal liver echogenicity is isoechoic or slightly hyperechoic to falciform fat, gallbladder walls are <2 mm when distended, and the common bile duct diameter is typically <5 mm; deviations suggest lipidosis, cholecystitis, or biliary obstruction, respectively.
- Ultrasound sensitivity for feline pancreatitis is limited (reported as low as 24% in some studies), with characteristic findings including a hypoechoic pancreas and surrounding hyperechoic mesentery, necessitating correlation with serum feline pancreatic lipase immunoreactivity (fPLI).
- Extrahepatic biliary obstruction is often identified by gallbladder and common bile duct distension (>4 mm), frequently secondary to pancreatitis or cholangiohepatitis, and distinguishing neoplastic from non-neoplastic causes is critical for prognosis.
- Chronic kidney disease is supported by increased renal cortical echogenicity and reduced corticomedullary distinction, but these findings are nonspecific, and diagnosis relies on persistent azotemia and inadequate urine concentrating ability.
- A structured assessment sequence covering all abdominal organs is essential, and documentation must include technical quality, limitations, and measurements in orthogonal planes, with cine loops for dynamic structures to ensure comprehensive diagnostic reporting.

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Feline abdominal ultrasound is a core diagnostic modality in small animal practice, offering real-time assessment of parenchymal architecture, luminal contents, and perfusion without ionizing radiation. This article provides a structured reference for the practicing veterinarian, covering normal sonographic anatomy of the feline abdomen, technical considerations specific to the species, and the most clinically relevant abnormal findings encountered in daily practice. The content is organized to support diagnostic reasoning, from image acquisition through pattern recognition and interpretation.

The clinical questions this article addresses are practical ones. When does a feline liver appear normal on ultrasound, and what changes should prompt further investigation? How reliable is ultrasonography for diagnosing feline pancreatitis, and what are its documented limitations? Which biliary findings distinguish extrahepatic obstruction from hepatocellular disease? Each section builds on the last, giving the reader a framework for interpreting images in the context of the whole patient.

This reference assumes familiarity with basic ultrasound physics, transducer handling, and standard imaging planes. It does not replace hands-on training or specialty consultation. Where the evidence base is limited or contested, that uncertainty is stated explicitly. The goal is to help the clinician integrate ultrasound findings with history, physical examination, and laboratory data to reach a defensible diagnosis or a rational next step.

## At a Glance

| Parameter | Normal Finding | Clinical Relevance |
|---|---|---|
| Liver echogenicity | Isoechoic or slightly hyperechoic to falciform fat | Diffuse hyperechogenicity suggests lipidosis, steroid hepatopathy, or cirrhosis |
| Gallbladder wall thickness | Less than 2 mm when distended | Thickening may indicate cholecystitis or biliary obstruction |
| Common bile duct diameter | Less than 5 mm in most cats | Dilation raises suspicion for extrahepatic biliary obstruction |
| Pancreatic echogenicity | Isoechoic to surrounding mesentery | Focal hypoechogenicity with surrounding hyperechoic fat supports pancreatitis |
| Pancreatic duct diameter | Less than 2.5 mm | Dilation is a nonspecific sign of pancreatic disease |
| Renal cortical echogenicity | Hypoechoic to liver, isoechoic to spleen | Increased cortical echogenicity suggests chronic kidney disease |
| Urinary bladder wall thickness | 1 to 2 mm when moderately distended | Diffuse thickening indicates cystitis, focal mass requires cytology or biopsy |
| Splenic echogenicity | Homogeneous, fine granular pattern | Nodular lesions warrant fine-needle aspiration or biopsy |

## Technical Considerations in Feline Abdominal Ultrasound

Feline patients present specific challenges that influence image quality and diagnostic yield. Their small body size requires higher frequency transducers, typically 8 to 14 MHz for superficial structures and 5 to 8 MHz for deeper penetration in larger or obese cats. A microconvex or linear array probe with a small footprint improves acoustic coupling between the ribs and allows easier manipulation in the narrow intercostal spaces.

Preparation is critical. Food withholding for 8 to 12 hours reduces gastric gas and luminal content, improving visualization of the pancreas, liver, and biliary tree. The cat should be positioned in dorsal recumbency with the forelimbs pulled caudally to widen the subxiphoid window. Clipping the entire ventral abdomen from the xiphoid to the pubis is standard. Sedation is rarely required for diagnostic ultrasound alone, but gentle manual restraint or a towel wrap is often sufficient. If the patient is fractious, low-dose sedation may be used at the clinician's discretion, following current formulary guidance.

Artifacts are common in feline abdominal imaging. Acoustic shadowing from gas-filled bowel loops can obscure the pancreas and biliary structures. Reverberation artifact from the lung edge may mimic a diaphragmatic mass. The clinician should systematically resean any region where artifact is suspected, changing the transducer angle or patient position as needed. The American College of Veterinary Radiology provides professional resources on imaging standards and safety practices that are relevant to all veterinary ultrasonographers.

## Normal Feline Abdominal Anatomy

### Liver and Biliary System

The normal feline liver is homogeneous, with echogenicity similar to or slightly greater than the falciform fat and less than the spleen. The caudal vena cava and portal vein are visible within the hepatic parenchyma, with the portal vein walls appearing more echogenic than the venous walls. The gallbladder is anechoic with a thin, smooth wall. The common bile duct in cats is small, usually less than 5 mm in diameter, and may be difficult to identify in healthy animals.

### Pancreas

The feline pancreas is located in the cranial abdomen, with the right limb adjacent to the duodenum and the left limb extending toward the spleen. It is normally isoechoic to the surrounding mesentery, making it challenging to identify in many cats. The pancreatic duct is visible in some healthy animals and should measure less than 2.5 mm. The body of the pancreas lies caudal to the pylorus and is best imaged from a right-sided approach.

### Kidneys and Urinary Tract

Feline kidneys are smooth, bean-shaped structures with a distinct corticomedullary junction. The cortex is normally hypoechoic to the liver and isoechoic to the spleen. The renal pelvis is not visible in the healthy cat. The urinary bladder wall is thin, measuring 1 to 2 mm when moderately distended, with a smooth luminal surface.

### Spleen and Gastrointestinal Tract

The spleen is homogeneous with a fine, granular echotexture. The stomach wall layers are visible as alternating hyperechoic and hypoechoic bands, with the muscularis layer appearing hypoechoic and the serosa hyperechoic. The small intestinal wall thickness in cats is normally less than 2.5 mm, and the five layers should be distinguishable in a longitudinal section.

## Pathophysiology of Common Abnormal Findings

### Pancreatitis

Feline pancreatitis is a diagnostic challenge. Clinical signs are nonspecific, with anorexia and lethargy reported in the majority of affected cats. The sensitivity of abdominal ultrasound for detecting feline pancreatitis is limited. One study of 21 cats with confirmed pancreatitis reported an ultrasound sensitivity of only 24%, while serum feline trypsin-like immunoreactivity showed a sensitivity of 86% using a cut-off of 49 micrograms per liter. A later prospective study found that ultrasound was 80% sensitive in cats with moderate to severe pancreatitis, but the authors emphasized that a normal ultrasound does not exclude the disease. The specificity of ultrasound for feline pancreatitis is high, meaning that when characteriztic changes are present, they are meaningful. These changes include a hypoechoic pancreas, surrounding hyperechoic mesentery due to saponification, and pancreatic duct dilation. The feline pancreatic lipase immunoreactivity assay is more sensitive than ultrasound, and current guidance recommends combining serum fPLI with imaging instead of relying on ultrasound alone.

### Extrahepatic Biliary Obstruction

Extrahepatic biliary obstruction in cats is most often caused by inflammatory disease, including pancreatitis, cholangiohepatitis, cholelithiasis, and cholecystitis, instead of by neoplasia. In a case series of 22 cats with surgically or necropsy-confirmed obstruction, distension of the common bile duct and gallbladder was the most common ultrasound finding. Hyperbilirubinemia was present in all cases. The distinction between obstructive and hepatocellular jaundice is a central diagnostic question. A dilated common bile duct, particularly when accompanied by a distended gallbladder and a normal or enlarged liver, supports obstruction. However, the absence of duct dilation does not rule out obstruction, especially in early or intermittent disease. The prognosis for cats with neoplastic obstruction is poor, with 100% mortality reported in one series, while non-neoplastic causes carried a 40% mortality.

### Chronic Kidney Disease

Chronic kidney disease is common in older cats, and ultrasound can support the diagnosis by demonstrating increased cortical echogenicity, reduced corticomedullary distinction, and reduced kidney size. These findings are not specific, and normal ultrasound does not exclude early disease. The diagnosis rests on persistent azotemia, inadequate urine concentrating ability, and consistent clinical signs, with ultrasound serving as a supporting test instead of a standalone diagnostic.

## Diagnostic Approach to Feline Abdominal Ultrasound

### Structured Assessment Sequence

Begin every feline abdominal study with a systematic sweep that covers the liver, gallbladder, spleen, stomach, pancreas, kidneys, adrenal glands, intestines, and urinary bladder. The order matters less than the discipline of completing all regions in every patient, regardless of the presenting complaint. A focused study that stops at the obvious abnormality risks missing concurrent disease, which is common in cats with pancreatitis and cholangiohepatitis.

Record the following in every patient: body condition score, bladder distension, stomach and bowel contents, and the presence of peritoneal fluid. Peritoneal fluid in cats is always significant. A small volume of anechoic fluid between the liver lobes or around the bladder can be the first clue to feline infectious peritonitis, neoplasia, or right-sided congestive heart failure.

### Decision Points That Change the Study

The clinical question determines how much time you spend in each region. A cat with suspected pancreatitis needs careful evaluation of the pancreas, duodenum, and biliary tree as a unit. A cat with chronic kidney disease needs renal measurements, cortical echogenicity assessment, and evaluation of the ureters and bladder. A cat with suspected extrahepatic biliary obstruction needs the extrahepatic bile duct traced from the hilus to the duodenal papilla, also a subjective look at the gallbladder.

Patient status changes the protocol. A fractious cat may only tolerate a limited study. In that situation, prioritize the region most likely to answer the clinical question and document what could not be assessed. A cat with respiratory distress should not be placed in dorsal recumbency for prolonged periods. Lateral recumbency with the transducer angled toward the dependent side often provides adequate images of the liver and spleen while preserving respiratory comfort.

### Equipment Choices That Matter

A microconvex or phased-array transducer with a frequency range of 6 to 10 MHz is the standard choice for feline abdominal work. Linear transducers at 10 to 14 MHz give excellent near-field resolution for the pancreas and adrenal glands but have a narrow footprint that makes complete liver evaluation tedious. Curvilinear transducers with lower frequencies, 4 to 6 MHz, are needed for deep-chested or obese cats but sacrifice resolution.

Use the highest frequency that penetrates the target organ. For a 4 kg cat, this usually means 8 to 10 MHz for superficial structures and 6 to 8 MHz for the liver and kidneys. Adjust the focal zone to the depth of the structure of interest. A single focal zone placed at the correct depth produces sharper images than multiple zones that slow the frame rate and blur moving structures.

### Normal Measurement Tables and Common Abnormality Checklist

The following tables provide reference ranges for clinically important feline abdominal structures. These values are drawn from standard veterinary imaging references and should be interpreted in the context of the individual patient, not applied as absolute cut-offs.

| Structure | Measurement | Normal Range | Clinical Significance |
|---|---|---|---|
| Liver, caudal right lobe | Thickness | Less than 1.0 cm | Thickening suggests hepatomegaly or infiltration |
| Gallbladder wall | Thickness | Less than 1.5 mm | Thickening suggests cholecystitis or edema |
| Common bile duct | Diameter | Less than 4 mm | Dilation suggests obstruction or cholangitis |
| Pancreatic left limb | Thickness | Less than 1.0 cm | Thickening suggests pancreatitis or neoplasia |
| Renal length | Sagittal | 3.0 to 4.3 cm | Smaller kidneys suggest chronic kidney disease |
| Renal cortical thickness | Ratio to medulla | 1.0 to 1.5 | Cortical thinning suggests chronic disease |
| Adrenal gland | Thickness | Less than 5 mm | Thickening suggests hyperplasia or neoplasia |
| Duodenal wall | Thickness | Less than 3.5 mm | Thickening suggests inflammatory bowel disease or neoplasia |
| Urinary bladder wall | Thickness, moderately distended | Less than 2 mm | Thickening suggests cystitis or neoplasia |

| Common Abnormality | Ultrasound Finding | Differential Prioritization |
|---|---|---|
| Hepatomegaly | Rounded liver margins, thickened lobes, increased echogenicity | Lipidosis, lymphoma, cholangiohepatitis, congestion |
| Gallbladder sludge | Echogenic bile with gravity-dependent layering | Stasis, anorexia, cholestasis, normal in some cats |
| Bile duct dilation | Common bile duct greater than 4 mm, tortuous course | Extrahepatic biliary obstruction, cholangitis, pancreatitis |
| Pancreatic enlargement | Thickened hypoechoic pancreas, surrounding hyperechoic fat | Pancreatitis, pancreatic neoplasia, pancreatic edema |
| Renal pyelectasia | Renal pelvis greater than 2 mm | Dehydration, diuresis, ureteral obstruction, pyelonephritis |
| Renal cortical hyperechogenicity | Cortex brighter than spleen or liver | Chronic kidney disease, acute kidney injury, nephrocalcinosis |
| Splenomegaly | Thickened spleen with rounded margins | Lymphoma, mast cell disease, extramedullary hematopoiesis, congestion |
| Thickened small intestine | Wall greater than 3.5 mm, loss of layering | Inflammatory bowel disease, lymphoma, infectious enteritis |
| Peritoneal effusion | Anechoic or echogenic fluid | Feline infectious peritonitis, neoplasia, cardiac failure, hypoalbuminaemia |

### Pancreatic Assessment in Practice

The feline pancreas is a thin, hypoechoic structure that can be difficult to identify in normal cats. The left limb lies caudal to the stomach and dorsal to the spleen. The right limb sits adjacent to the descending duodenum. In healthy cats, the pancreas may be invisible or appear as a subtle hypoechoic band. When it is visible, measure the thickness and compare it to the adjacent duodenal wall.

Ultrasound is specific for feline pancreatitis when changes are present, but sensitivity is limited. One study of 21 cats with confirmed pancreatitis reported an ultrasound sensitivity of 24 percent, while serum feline trypsin-like immunoreactivity achieved 86 percent sensitivity at a cut-off of 49 micrograms per liter [comparison of diagnostic tests for pancreatitis in cats](https://pubmed.ncbi.nlm.nih.gov/11467589/). A later prospective study found that abdominal ultrasound was 80 percent sensitive in cats with moderate to severe pancreatitis, with serum feline pancreatic lipase immunoreactivity reaching 100 percent sensitivity in the same group [evaluation of serum feline pancreatic lipase immunoreactivity and helical computed tomography](https://pubmed.ncbi.nlm.nih.gov/15638263/). These figures reflect the spectrum of disease severity. Mild pancreatitis frequently produces no detectable ultrasound changes.

The ultrasonographic features of feline pancreatitis include pancreatic enlargement, hypoechoic parenchyma, hyperechoic mesenteric fat surrounding the pancreas, and peritoneal effusion. The common bile duct may dilate if the inflamed pancreas compresses the duct as it passes through the duodenal wall. A normal pancreatic ultrasound does not exclude pancreatitis. Combine imaging with serum feline pancreatic lipase immunoreactivity and clinical assessment when pancreatitis is suspected [diagnosis of pancreatitis](https://pubmed.ncbi.nlm.nih.gov/14552167/).

### Biliary Obstruction Assessment

Extrahepatic biliary obstruction in cats produces a characteriztic pattern: a distended gallbladder, a dilated common bile duct, and a visible obstruction point. The most common causes are pancreatic adenocarcinoma, cholangiohepatitis with inspissated bile, cholelithiasis, and pancreatitis. In a series of 22 cats with confirmed extrahepatic biliary obstruction, distension of the common bile duct and gallbladder was the most frequently observed ultrasound finding [pathogenesis and outcome of extrahepatic biliary obstruction in cats](https://pubmed.ncbi.nlm.nih.gov/12074289/).

Trace the common bile duct from the liver hilus to the duodenum. A duct greater than 4 mm in diameter is dilated. Look for the cause of obstruction: a hyperechoic shadowing focus suggests a cholelith, a mass at the pancreaticoduodenal junction suggests neoplasia, and diffuse pancreatic thickening with peripancreatic fat changes suggests pancreatitis. The distinction matters for prognosis. In the same series, mortality was 100 percent in cats with underlying neoplasia and 40 percent in cats with non-neoplastic causes [pathogenesis and outcome of extrahepatic biliary obstruction in cats](https://pubmed.ncbi.nlm.nih.gov/12074289/).

### Documentation Standards

Record images in two orthogonal planes for every abnormal finding. Measure lesions in three dimensions where possible. Store cine loops for vascular structures and for the pancreas, where subtle changes are easier to appreciate in motion. Write a structured report that lists each organ system, states whether it was normal or abnormal, and describes any abnormality with location, size, echogenicity, and effect on adjacent structures.

Include a statement about the technical quality of the study. A limited study due to patient compliance or body condition should be documented explicitly so the next clinician knows the degree of confidence to place in negative findings. This is particularly important in cats, where a normal pancreatic ultrasound does not rule out pancreatitis and a normal renal ultrasound does not rule out early chronic kidney disease.

## Recognized Complications and Early Detection

Ultrasound-guided procedures in the feline abdomen carry specific risks. Hemorrhage after fine-needle aspiration of the spleen or kidney occurs in a small percentage of cases and is usually self-limiting, but coagulopathic cats may bleed persistently. Detect hemorrhage early by scanning the needle tract and the capsule immediately after sampling, then re-scanning the site at 5 to 10 minutes. Anechoic or hypoechoic fluid accumulating around the puncture site indicates active bleeding.

Bile peritonitis is the most serious complication of gall bladder aspiration or cholecystocentesis. Leakage may be immediate or delayed. Scan the gall bladder wall and the perihepatic space for 10 minutes after the procedure. Newly appearing free fluid, a collapsing gall bladder lumen, or a visible tear at the puncture site should prompt immediate surgical consultation. Avoid gall bladder aspiration whenever a distended common bile duct suggests downstream obstruction, because decompression of a hypertensive biliary tree increases leak risk.

Pneumothorax can follow aspiration of cranial abdominal masses, particularly those in the liver or right limb of the pancreas that lie close to the diaphragm. Detect it by scanning the pleural space through an intercostal window after the procedure. The presence of a sliding lung sign does not exclude a small pneumothorax, so thoracic ultrasound should be combined with auscultation and, where available, thoracic radiography.

## Common Errors and Corrective Actions

The most frequent error in feline abdominal ultrasound is mistaking the normal right limb of the pancreas for a mesenteric mass. The right limb lies between the duodenum and the right kidney, is isoechoic to surrounding fat in many cats, and may be difficult to identify. Correct this by locating the duodenum first, then scanning medially. The pancreas is the only structure in that region that runs parallel to the duodenum and has a visible pancreatic duct.

A second common error is overinterpreting mild pyelectasis. In cats, a renal pelvis of 1 to 2 mm is within normal limits in many individuals, particularly when the bladder is distended. Do not diagnose hydronephrosis unless the pelvis exceeds 3 mm or the ureter is visibly dilated. Serial measurement over 24 hours with a consistent bladder volume is more informative than a single reading.

A third error is attributing a thickened gall bladder wall to cholecystitis when the thickening is artefactual. Gall bladder wall thickness is overestimated when the beam strikes the wall obliquely. Correct this by ensuring the wall is perpendicular to the beam and by measuring at the fundus instead of the neck.

A fourth error is failing to distinguish the splenic vein from the pancreatic duct. Both appear as anechoic tubular structures in the left cranial abdomen. The splenic vein can be traced to the splenic hilus and has a visible wall. The pancreatic duct is smaller, runs within the pancreatic parenchyma, and does not connect to the spleen.

| Observation | Likely cause | Discriminating check |
|---|---|---|
| Hypoechoic mass between duodenum and right kidney | Normal right pancreatic limb | Trace duodenum, identify pancreatic duct, compare echogenicity to left limb |
| Renal pelvis 2 to 3 mm | Normal variant or mild pyelectasis | Repeat with empty bladder, check ureter diameter |
| Thickened gall bladder wall | Oblique beam artefact | Reposition to perpendicular, measure at fundus |
| Tubular structure in left cranial abdomen | Splenic vein versus pancreatic duct | Trace vessel to splenic hilus, assess wall echogenicity |
| Free fluid after aspiration | Hemorrhage or bile leak | Re-scan at 5 and 10 minutes, assess fluid echogenicity, check gall bladder wall |

## Limitations of Current Evidence

The sensitivity of abdominal ultrasound for feline pancreatitis is consistently reported as low. One comparative study of diagnostic tests in 21 cats with confirmed pancreatitis found an ultrasound sensitivity of 24%, while serum feline trypsin-like immunoreactivity reached 86% at a cut-off of 49 microg/L [Gerhardt et al., comparison of diagnostic tests for pancreatitis in cats](https://pubmed.ncbi.nlm.nih.gov/11467589/). A later prospective study reported that ultrasound was 80% sensitive in cats with moderate to severe pancreatitis but did not establish sensitivity in mild disease [Forman et al., evaluation of serum feline pancreatic lipase immunoreactivity and helical computed tomography](https://pubmed.ncbi.nlm.nih.gov/15638263/). Expert opinion holds that ultrasound is highly specific for pancreatitis when changes are present, but a normal study does not exclude the disease [Steiner, diagnosis of pancreatitis](https://pubmed.ncbi.nlm.nih.gov/14552167/). The evidence base for chronic pancreatitis in cats is even thinner, and extrapolation from canine data, where ultrasound detected abnormalities in only 56% of histologically confirmed cases, may not apply directly [Watson et al., observational study of chronic pancreatitis in dogs](https://pubmed.ncbi.nlm.nih.gov/21262713/).

## Referral and Escalation Criteria

Refer for specialist ultrasonography or computed tomography when the study is technically limited, when a mass cannot be fully characterized, or when ultrasound-guided sampling is required and the target is small or deeply located. The American College of Veterinary Radiology maintains specialty standards and can direct practitioners to board-certified imaging services [ACVR resources on diagnostic imaging practice](https://acvr.org/). Laboratory involvement is indicated when pancreatic enzyme concentrations are discordant with imaging findings, because serum feline pancreatic lipase immunoreactivity and trypsin-like immunoreactivity provide complementary information [MSD Veterinary Manual diagnostic approach](https://www.msdvetmanual.com/).

Regulatory reporting is rarely triggered by abdominal ultrasound findings in cats. Report suspected foreign animal diseases, including those with abdominal manifestations, to the relevant animal health authority. The World Organization for Animal Health publishes notifiable disease standards that define reporting obligations [WOAH terrestrial animal health code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/).

## Frequently Asked Questions

### How Should I Adjust My Pancreatic Assessment When Only a Low-Frequency Curvilinear Probe Is Available?

A low-frequency curvilinear probe can still identify a normal feline pancreas, but sensitivity for subtle parenchymal change falls. The feline right pancreatic limb sits caudal to the pylorus and duodenum, and the left limb lies caudal to the stomach body. With a 5 to 8 MHz curvilinear footprint, search for the hypoechoic, finely textured pancreas by locating the duodenum and following its mesenteric border. Hyperechoic mesenteric fat often obscures the gland, so use graded compression and adjust focal zones to the near field. If the pancreas cannot be visualized, do not report it as normal. State that pancreatic assessment was limited by probe frequency and patient conformation, and recommend a higher-frequency linear array or referral. Ultrasound sensitivity for feline pancreatitis is low even under ideal conditions, so a normal study does not exclude disease, as noted in [comparative diagnostic test sensitivity data for feline pancreatitis](https://pubmed.ncbi.nlm.nih.gov/11467589/).

### What Is the Minimum Ultrasound Study I Should Record for a Cat With Suspected Biliary Obstruction?

Record the gallbladder lumen and wall in two planes, the common bile duct at its widest point, and the duodenal papilla. Measure the common bile duct perpendicular to its long axis and document the diameter. Capture the liver parenchyma, including the porta hepatis, and note any dilated intrahepatic bile ducts. Include the pancreas and both kidneys, because inflammatory disease in these organs commonly accompanies biliary obstruction in cats. Store cine loops of the gallbladder and common bile duct to document peristalsis and distinguish a truly dilated duct from a transiently distended one. In cats with confirmed extrahepatic biliary obstruction, gallbladder and common bile duct distension is the most frequently reported ultrasound finding, per [outcome data on feline extrahepatic biliary obstruction](https://pubmed.ncbi.nlm.nih.gov/12074289/). Record the study before any therapeutic decompression so the pre-intervention anatomy is preserved.

### How Do I Explain an Inconclusive Pancreatic Ultrasound to an Owner Who Wants a Definitive Answer?

Explain that ultrasound images the pancreas indirectly, through surrounding fat and bowel gas, and that a normal appearance does not rule out pancreatitis. State that the feline pancreas is small and often difficult to see completely, and that published sensitivity for ultrasound in feline pancreatitis is approximately 24 to 35 percent, as reported in [early comparative work on feline pancreatitis diagnostics](https://pubmed.ncbi.nlm.nih.gov/11467589/). Offer the next diagnostic step: serum feline pancreatic lipase immunoreactivity, which has shown higher sensitivity in cats with moderate to severe disease, according to [evaluation of feline pancreatic lipase immunoreactivity and helical computed tomography](https://pubmed.ncbi.nlm.nih.gov/15638263/). Frame the ultrasound as one component of a panel, not a standalone test. Avoid promising a definitive answer from imaging alone, and outline the cost and yield of each additional test so the owner can choose.

### When Should I Refer a Cat for Advanced Imaging instead of Repeat a Nondiagnostic Ultrasound?

Refer when the clinical question cannot be answered by the available equipment or when the initial study is technically inadequate despite optimization. Suspected pancreatic masses, deep retroperitoneal disease, or suspected portosystemic shunting warrant referral for computed tomography or a high-end ultrasound unit with microconvex and linear transducers. Refer also when the cat is unstable and a single, complete study is needed to guide surgery, because repeated partial studies delay care. If the primary concern is pancreatitis and the ultrasound is normal but clinical signs persist, proceed with serum fPLI testing before referral, since [serum fPLI is the most sensitive noninvasive test for feline pancreatitis](https://pubmed.ncbi.nlm.nih.gov/14552167/). Referral is appropriate when the answer will change management, also when the image is imperfect.

### What Documentation Is Required When a Feline Abdominal Ultrasound Is Performed in General Practice?

Document patient signalment, indication, probe type and frequency, and the complete list of organs assessed. For each organ, record whether it was normal, abnormal, or not visualized, and describe any abnormality with location, size, echogenicity, and vascularity. Store representative images and cine loops in the medical record, labelled with patient identification and date. Record any complications, such as patient intolerance or suspected needle tract hemorrhage after sampling. Note limitations explicitly, including poor acoustic windows or incomplete organ visualization. The [American College of Veterinary Radiology resources](https://acvr.org/) provide professional standards for image archiving and study interpretation. A written report should separate sonographic findings from interpretation, and should state a differential list instead of a single diagnosis when findings are nonspecific.

### How Does Feline Abdominal Ultrasound Differ From Canine Abdominal Ultrasound in Routine Practice?

The feline pancreas is smaller, more mobile, and more often obscured by gas and fat than the canine pancreas, so a complete pancreatic study is harder to achieve. Feline biliary disease frequently coexists with pancreatitis, so the biliary tree and pancreas must be assessed together in every jaundiced cat. The feline gallbladder is more variable in shape and position, and a normal common bile duct diameter is smaller than in most dogs. Feline kidneys are more likely to show chronic interstitial changes that are incidental, so correlate ultrasound findings with biochemistry before diagnosing chronic kidney disease. The [MSD Veterinary Manual](https://www.msdvetmanual.com/) provides species-specific reference values for organ dimensions and normal sonographic appearance. In practice, allow more time for the feline study and lower your threshold for repeating the examination under sedation.

## Related Clinical & Scientific Guides

* [MRI Monitoring of Brain Tumor Response to Therapy in Dogs](/knowledge/veterinary-medicine/diagnostic-imaging/mri-monitoring-brain-tumor-response-therapy-dogs)
* [Ultrasound-Guided Drainage of Abscesses in Small Animals](/knowledge/veterinary-medicine/diagnostic-imaging/ultrasound-guided-drainage-abscesses-small-animals)
* [Radiographic Monitoring of Total Hip Replacement in Dogs](/knowledge/veterinary-medicine/diagnostic-imaging/radiographic-monitoring-total-hip-replacement-dogs)


## References and Further Reading

- [Comparison of the sensitivity of different diagnostic tests for pancreatitis in cats.](https://pubmed.ncbi.nlm.nih.gov/11467589/). 2001.
- [Evaluation of serum feline pancreatic lipase immunoreactivity and helical computed tomography versus conventional testing for the diagnosis of feline pancreatitis.](https://pubmed.ncbi.nlm.nih.gov/15638263/). 2004.
- [Diagnosis of pancreatitis.](https://pubmed.ncbi.nlm.nih.gov/14552167/). 2003.
- [Observational study of 14 cases of chronic pancreatitis in dogs.](https://pubmed.ncbi.nlm.nih.gov/21262713/). 2010.
- [Pathogenesis and outcome of extrahepatic biliary obstruction in cats.](https://pubmed.ncbi.nlm.nih.gov/12074289/). 2002.
- [Extrarenal Wilms' tumor: staging, treatment, and prognosis.](https://pubmed.ncbi.nlm.nih.gov/1845874/). 1991.
- [American College of Veterinary Radiology Resources](https://acvr.org/). American College of Veterinary Radiology.
- [MSD Veterinary Manual, Professional Edition](https://www.msdvetmanual.com/). MSD Veterinary Manual.
- [American Veterinary Medical Association Practice Resources](https://www.avma.org/resources-tools). American Veterinary Medical Association.

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> This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.