Diagnostic imaging in veterinary medicine: ultrasound, X-rays, and endoscopy
Technical guide for clinical veterinarians · Colombia 2026
Diagnostic imaging in veterinary medicine: ultrasound, X-rays and endoscopy
How to choose the right imaging modality based on the clinical case, species and resources available in your veterinary clinic
Diagnostic imaging is the cornerstone of modern veterinary clinical diagnosis. The ability to see inside the patient without surgery has transformed veterinary medicine over the last two decades — and today, clinics without at least two imaging modalities are limited in their ability to resolve complex cases. The challenge for the veterinarian is not just having the equipment, but knowing when to use each modality and how to interpret it correctly.
This guide compares the three main imaging modalities in veterinary medicine — ultrasound, radiography and endoscopy — and explains when to use each one, what information it provides and how to integrate them into the daily clinical diagnostic workflow.
1. The three imaging modalities in veterinary medicine
Each imaging modality has distinct strengths and limitations. The expert clinical veterinarian does not choose just one — they combine them strategically based on the case:
| Modality | Best for visualizing | Main limitation | Equipment cost | Availability |
|---|---|---|---|---|
| Ultrasound | Soft tissues, organs, fluids, pregnancy, heart | Gas and bone block the image | $15M–$80M COP | High in clinics |
| X-rays (radiography) | Bones, lungs, radiopaque foreign bodies, thorax | Does not differentiate similar soft tissues | $20M–$90M COP | High in clinics |
| Endoscopy | Digestive and respiratory mucosae, foreign bodies, biopsies | Only accessible airways with the endoscope | $15M–$60M COP | Medium — specialized clinics |
| Veterinary CT | Skull, spine, nose, complex joints | Requires general anesthesia + expensive equipment | $300M+ COP | Low — referral centers |
| Magnetic resonance imaging | CNS, spinal cord, high-resolution soft tissues | Anesthesia + very expensive equipment + duration | $800M+ COP | Very low — universities and specialized centers |
2. Veterinary ultrasound: when it is the first choice
Ultrasound is the fastest-growing imaging modality in Colombian veterinary clinics over the last five years. Its main advantage is that it provides real-time imaging of soft organs — exactly what the veterinarian needs in most cases of internal medicine.
Indications where ultrasound is first-line
- Acute abdomen: when the animal arrives with abdominal pain, vomiting, distension or weakness, abdominal ultrasound in less than 5 minutes can identify free fluid (hemoperitoneum, peritonitis), intestinal intussusception, splenic torsion or retroperitoneal mass.
- Pregnancy diagnosis: detection from 20–25 days in dogs, 15–21 days in cats. Ultrasound is indispensable for confirming fetal viability, counting offspring and estimating the due date.
- Pyometra vs. pseudopregnancy: differentiation of pregnant uterus, open and closed pyometra. The ultrasound diagnosis determines whether emergency surgery is needed or if the patient should be stabilized first.
- Renal evaluation: size, architecture, dilated pelvis, cysts, masses. Renal ultrasound complements the biochemical profile in chronic kidney disease.
- Cavity effusion: the FAST-Vet protocol detects fluid in the abdominal and pericardial cavity in minutes, guiding the decision to perform or not an emergency puncture.
- Procedural guidance: liver biopsy, mass aspiration, cyst puncture, guided catheter placement. Ultrasound reduces the risk of complications in blind procedures.
When ultrasound is NOT sufficient
- Radiopaque foreign body: metal and bone block ultrasound. X-rays are more reliable for locating needles, hooks, bones and other dense foreign bodies.
- Evaluation of air-filled lungs: ultrasound does not penetrate healthy lung tissue. For pneumonia, pleural effusion, lung mass and tension pneumothorax, chest X-rays are superior.
- Fractures and bone pathology: bone completely reflects ultrasound. Radiography is the standard for fractures, bone lysis and joint injuries.
3. Veterinary radiography: when it is essential
Radiography remains indispensable in specific areas of veterinary medicine. Its main advantage is the visualization of the skeleton and thorax with a clarity that no other modality matches in terms of cost-effectiveness.
🦴
Traumatology and orthopedics
Diagnosis and classification of fractures, post-surgical implant evaluation, hip dysplasia (PennHIP or standard protocol), osteosarcoma, osteomyelitis. Minimum of two orthogonal projections.
Projections: lateral + VD/DV of the segment
🫁
Thoracic pathology
Pneumonia, tracheal collapse, chronic bronchitis, megaesophagus, mediastinal masses, pleural effusion, lung metastases. Chest X-ray is the first step in any animal with cough, dyspnea or syncope.
Projections: lateral + VD or DV
🔍
Foreign bodies
Detection of radiopaque foreign bodies (bones, metals, stones). Radiolucent foreign bodies (plastic, fabric, wood) are invisible on X-rays but can be seen with ultrasound or endoscopy.
Simple lateral abdomen + VD
🐕
Geriatric and oncological assessment
Tumor staging (search for lung metastases), cardiac silhouette evaluation in cardiac patients, preoperative assessment in animals over 7 years old.
Thorax 3 projections for metastases
4. Veterinary endoscopy: the third diagnostic pillar
Endoscopy is the third imaging modality in veterinary medicine and the least available in first-level clinics. However, it is indispensable for the diagnosis of digestive and respiratory pathology in certain cases:
- Gastric foreign body removal: flexible endoscopy allows the removal of foreign bodies from the stomach without abdominal surgery in most cases — saving a laparotomy and its recovery.
- Digestive mucosa biopsy: diagnosis of inflammatory bowel disease (IBD), small cell digestive lymphoma, chronic gastritis. Endoscopic biopsy is essential because the histology of the mucosa changes the treatment.
- Esophagus and stomach evaluation: reflux esophagitis, megaesophagus, gastric polyps, ulcers, helicobacter. Direct visualization of the mucosa surpasses any indirect imaging modality.
- Respiratory endoscopy: evaluation of larynx, trachea and bronchi. Diagnosis of tracheal collapse, polyps, foreign bodies in the airway and bronchoalveolar lavage (BAL) for culture and cytology.
- Colonoscopy: diagnosis of chronic colitis, colon polyps, colorectal obstruction.
Key decision: Veterinary endoscopy requires general anesthesia in 100% of cases in animals — unlike human endoscopy where many procedures are done under sedation. This adds complexity and cost, but also guarantees that the animal remains still for a quality examination. Preoperative anesthetic evaluation is mandatory before any veterinary endoscopy.
5. Decision algorithm: which imaging to use first?
1
Animal with gastrointestinal symptoms (vomiting, diarrhea, anorexia, abdominal pain)
→ Abdominal ultrasound first. If there is suspicion of a radiopaque foreign body or excessive gas → add X-rays. If it persists without a diagnosis and there is suspicion of mucosa → endoscopy.
2
Animal with dyspnea, cough or respiratory symptoms
→ Chest X-rays first (2 projections). If there is pleural effusion → ultrasound to guide thoracocentesis. If there is suspicion of tracheal or bronchial injury → respiratory endoscopy.
3
Acute trauma or lameness
→ X-rays first for fractures and dislocations. If there is suspicion of soft tissue injury (ligament rupture, muscle hematoma, hernia) → complementary ultrasound.
4
Cardiological emergency (syncope, abdominal distension, heart murmur)
→ Cardiac ultrasound + immediate FAST-Vet protocol. Complementary chest X-ray to evaluate silhouette and pulmonary edema.
5
Pregnancy or reproduction monitoring
→ Ultrasound always as the first and only modality needed in most cases. X-rays at the end of pregnancy for bone fetus counting if there is doubt about the number.
6. How to progressively equip a veterinary clinic
| Stage | Equipment | Approx. investment COP | Cases it resolves |
|---|---|---|---|
| Level 1 — Basic office | Portable ultrasound with convex probe | $15M–$22M | Pregnancy, basic abdomen, FAST emergencies |
| Level 2 — First-level clinic | Ultrasound + Digital X-ray | $40M–$70M | 80% of imaging cases |
| Level 3 — Specialized clinic | + Ultrasound with cardiac Doppler + linear probe | +$20M–$35M | Cardiology, MSK, guided procedures |
| Level 4 — Referral hospital | + Flexible endoscope + video tower | +$20M–$45M | Complete digestive and respiratory endoscopy |
| Level 5 — Specialized center | + Veterinary CT | +$200M+ | Neurology, oncology, referral surgery |
Recommendation for Colombia 2025: The combination of level 2 (mid-range ultrasound + digital X-ray) resolves 80% of the imaging cases that arrive at a medium-complexity veterinary clinic. It is the investment with the greatest diagnostic impact per invested weight. Level 3 with cardiac Doppler increases the capacity to more than 90% of cases.
Do you want to equip your veterinary clinic with diagnostic imaging?
We will advise you on the optimal combination of equipment according to the type of animals you treat and your budget in Colombia.
Veterinary imaging equipment available in Colombia
Ultrasound machines, X-rays and endoscopy equipment for veterinary clinics with local technical support and available financing.
View veterinary catalog →
Subscribe Us
Subscribe to our newsletter and receive a selection of cool articles every weeks
