BXL
Aspiración con aguja fina (FNA) guided by Ecografía veterinaria has become a cornerstone in modern large-animal practice. Se utiliza para tomar muestras de tejidos, como los ganglios linfáticos., hígado, o masas en el ganado, caballos, and small ruminants, this technique provides veterinarians with a minimally invasive method to gather diagnostic information quickly and efficiently. Although ultrasound-guided FNA is widely used in small animal clinics, its benefits are increasingly being recognized in livestock settings as well.
Getting better at FNA ultrasound doesn’t only mean better diagnostic outcomes—it also means reduced stress for animals, faster decisions, and lower treatment costs. As a livestock operator or veterinarian working with farm animals, improving your FNA ultrasound technique can significantly impact herd health and operational efficiency.
En este artículo, we’ll explore key ways to improve your skills in FNA veterinary ultrasound, guided by the latest insights from international veterinary bodies and authoritative sources.
References from veterinary authorities:
-
“Ultrasound-Guided Fine-Needle Aspiration and Biopsy” – Today’s Veterinary Practice, https://todaysveterinarypractice.com/ultrasound-guided-fine-needle-aspiration-and-biopsy/
-
“Ultrasonography in Cattle Practice” – Veterinary Clinics of North America: Food Animal Practice, https://www.sciencedirect.com/journal/veterinary-clinics-of-north-america-food-animal-practice
-
“Diagnostic Ultrasonography in Veterinary Medicine” – Merck Veterinary Manual, https://www.merckvetmanual.com
Understanding the Purpose of FNA in Farm Animals
Fine-needle aspiration allows you to sample internal structures like superficial lymph nodes, abscesos, masses, and even certain organs. Unlike core biopsies, FNA is less invasive and can often be performed chute-side or in the field with portable ultrasound equipment. When properly executed, FNA provides cytological samples that help detect infections, inflammation, neoplasia, and other abnormalities without the need for surgical intervention.
Essential Equipment and Setup
Before you can master the procedure, it’s crucial to ensure you’re using the right tools:
-
Ultrasound machine with linear or convex transducer (3.5–8 MHz for large animals)
-
Long, fine-gauge aspiration needles (typically 20–22 gauge)
-
5–10 mL syringes
-
Alcohol or gel for skin contact
-
Clipping tools for preparing the area
-
Protective gloves and sterile field supplies
Ensure the ultrasound machine offers needle visualization features like beam steering or needle-enhancement mode to help guide your needle tip accurately. Portátil, battery-powered units are especially useful for field operations in remote farms.
Pre-Procedure Considerations
Before inserting the needle, take these steps:
-
Clip and clean the targeted site to reduce contamination.
-
Apply ultrasound gel generously.
-
Adjust the depth, ganar, and frequency settings to clearly visualize the target.
-
Practice locating the lesion or mass in both longitudinal and transverse planes.
-
Calm and restrain the animal properly to reduce movement and stress.
Even slight movement can cause sampling errors or create difficulties in keeping the needle in view, so good restraint—either physical or chemical—is essential.
Ultrasound-Guided Technique: Step-by-Step
Here’s a general overview of how to perform an FNA using ultrasound:
-
Hold the transducer in your non-dominant hand and visualize the target.
-
With your dominant hand, insert the needle either in-plane (parallel to probe) or out-of-plane (perpendicular).
-
Maintain the needle tip within the field of view—this is critical.
-
Apply suction with the syringe once the needle is within the target.
-
Move the needle slightly back and forth to aspirate cells.
-
Release suction and withdraw the needle.
-
Prepare the sample slides immediately to preserve cell integrity.
Tips for Better Results
-
Use the shortest needle path possible to reach the target.
-
If visibility is poor, try fanning the transducer slightly or adjusting the angle.
-
In larger animals like cattle or horses, deeper targets may require lower-frequency probes (p ej., 3.5 MHz).
-
Perform practice scans regularly, even when not doing FNAs, to maintain imaging skills.
Interpreting Cytology Results
Cytologic interpretation should ideally be done by a trained veterinary pathologist. Sin embargo, field practitioners can still recognize certain features:
-
Purulent aspirates suggest abscesses or infections
-
Homogeneous small round cells may indicate lymphoma
-
Fatty material can signal lipomas or degenerative changes
Be aware of sample quality: hemorrhagic or poorly cellular smears may need repeat aspiration or an alternate site.
Common Challenges and How to Overcome Them
-
Poor needle visibility:
– Solution: use a steeper angle or select needle-enhancement mode on the ultrasound. -
Uncooperative animals:
– Solution: use mild sedation or better physical restraint. -
Blood contamination:
– Solution: avoid vascular structures by carefully reviewing the ultrasound image.
Continued Education and Training
Attending hands-on workshops and certification courses is one of the best ways to improve your FNA skills. Organizations such as the American Association of Bovine Practitioners (AABP) or the British Cattle Veterinary Association (BCVA) regularly offer practical training. Adicionalmente, online learning platforms like VetMedTeam or VetLexicon provide virtual learning modules.
Conclusión
Fine-needle aspiration guided by ultrasound is a powerful tool in the livestock health toolbox. By improving your technique, refining your image interpretation, and staying updated through training, you’ll be equipped to make better, faster decisions that support both animal welfare and farm productivity.
As with any veterinary technique, experience and consistency are key. Make it a routine part of your diagnostic approach and continue learning from each case. Your animals—and your bottom line—will thank you for it.