1. Ultrasound Guided
Biopsies
Wendy Blount, DVM
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2. Indications for US Guided Biopsy
Solid soft tissue masses visible by ultrasound
If mixed echo pattern, go for a solid spot
Take care aspirating fluid filled structures in body cavities
Aspirate the gall bladder only if you are prepared to do interventional surgery onsite
Aspirate GB only under sedation & with informed consent
Be prepared for interventional surgery for hypoechoic lesions in liver, spleen & other internal organs
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3. Indications for US Guided Biopsy
FNA of fluid filled uterus is never recommended
Percutaneous draining of local peritonitis, pancreatic abscesses, perinephric cysts can be attempted
Septic contamination of the peritoneal cavity less likely with these
Scanners with needle guides and needle path screen guides are nice
Take 2-3 samples for better results
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4. Indications for US Guided Biopsy
FNA of fluid filled uterus is never recommended
Percutaneous draining of local peritonitis, pancreatic abscesses, perinephric cysts can be attempted
Septic contamination of the peritoneal cavity less likely with these
Scanners with needle guides and needle path screen guides are nice
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5. Bob Stout – Nacogdoches TX
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6. Indications for US Guided Biopsy
FNA of fluid filled uterus is never recommended
Percutaneous draining of local peritonitis, pancreatic abscesses, perinephric cysts can be attempted
Septic contamination of the peritoneal cavity less likely with these
Scanners with needle guides and needle path screen guides are nice
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7. Patient & Equipment Preparation
Clip fur and do alcohol prep (no gel!)
If you are going to touch the entry site with your fingers, don sterile gloves for FNA
Don sterile gloves for core biopsies, and place a sterile glove or probe cover over the probe
Use sterile surgical lube under the probe cover as well as on the patient
May or may not need sedation for FNA
Sedation required for core biopsy
Consider scheduling all FNA/biopsies in the AM
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8. Triplett – Fisher Scientific
Patient & Equipment Preparation
Pre-Sampling Lab work – within 24 hours
CBC confirming platelets >50,000/ul
HCT >30% for dogs, HCT >25% for cats being sedated
Buccal Mucosal Bleeding Time (BMBT) <2 minutes
Jorvet - Surgicutt
Triplett – Fisher Scientific
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9. Patient & Equipment Preparation
Pre-Sampling Lab work
Buccal Mucosal Bleeding Time (BMBT) <2 minutes
Lift the upper lip (gauze muzzle)
Remove the device safety tab
Place the device on the mucosa
Push the device trigger button
Dab dripping blood every 15
seconds, but don’t touch the clot
6. BMBT = when bleeding stops
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10. Patient & Equipment Preparation
Pre-Sampling Lab work
Buccal Mucosal Bleeding Time (BMBT) <2 minutes
If liver disease, PT/PTT
Any preanesthetic lab work or other diagnostics indicated for safe anesthesia
Sterilize Needle Guide, if used
Some are disposable
Some gas sterilized, autoclaved or gluteraldehyde
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11. Patient & Equipment Preparation
Supplies
FNA needles – 22-25g for internals, any size for peripherals
1-1/2 inch, 3 inch spinal needles
Sterile core biopsy needles 18g – 14g
Can re-autoclave until dull
Measure and label needle throw path
5-12cc syringes for aspiration
Glass slides, stains, decent cytology microscope
Formaldehyde cups & cassettes for core biopsies
25g x 5/8” needles for teasing core biopsies out of needle
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12. Tips for US Guided FNA/Biopsy
Choose the shortest direct path between skin and the target
Try not to pass through more than one body cavity, and not more than one organ
Separate needle for each location
Indirect guidance – use US to find a good place, and then do a blind needle pass
Draping usually not necessary
Stab incision needed for core biopsy, but not FNA
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13. Free Hand vs. Needle Guide
Needle guides usually have a fixed angle of entry
Adjust the needle angle if freehand
Superficial structures best done freehand or with indirect guidance
Cover needle hub with finger to
prevent cells from inadvertently
entering the needle
When you reach lesion edge,
uncover hub and advance into the lesion
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14. Free Hand vs. Needle Guide
Fill syringe full of air
*then* attach needle filled with sample
Forcefully expel contents of needle onto the slide
Gently perform vertical pull
apart slides with pressure of
weight of slide only
Horizontal preps for bone marrow
or mesenchymal tumors
Make 5-10 slides of each lesion
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15. FNA vs. Core Biopsy FNA probably better for vascular areas
Core biopsy for large solid lesions
Check your FNA cytology, and if non-diagnostic, consider a core
Sacrifice a core biopsy for cytology to make sure you have a good sample
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16. FNA vs. Core Biopsy FNA probably better for vascular areas
Core biopsy for large solid lesions
Check your FNA cytology, and if non-diagnostic, consider a core
Sacrifice a core biopsy for cytology to make sure you have a good sample
Needle throw length
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17. Tips for FNA Try a “core” FNA first with no attached syringe
Less hemodilution
Attach air filled 10cc
syringe and propel
needle contents onto
a slide
Prep, dry and stain as
usual
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18. Tips for FNA Try a “core” FNA first with no attached syringe
Less hemodilution
If that fails, add aspiration with syringe
2cc saline in syringe for
better recovery on firm
lesions that produce scant
samples
Spin down & prep slides from
sediment
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19. Tips for FNA Try a “core” FNA first with no attached syringe
Less hemodilution
If that fails, add aspiration with syringe
2cc saline in syringe for better recovery on firm samples that produce scant samples
Spin down & prep slides from sediment
If that fails try a larger needle if deemed safe
Or a needle with stylet (spinal needle), followed by aspiration
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20. FNA/Biopsy of Liver
Difficult to impossible in deep chested dogs with small livers
Use the ultrasound to avoid pleural cavity when using intercostal approach
Liver biopsy/FNA for diffuse disease – left lobe
Use US to avoid GB and vessels
Penetrate through the capsule before deploying the Trucut to minimize bleeding
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21. FNA/Biopsy of Liver Indirect Ultrasound Guidance
Notch between xyphoid and costal arch
Choose needle length sufficient to penetrate
falciform ligament (at least 1-1/2“)
Check for liver presence with the US probe
Clip & surgically prep the area
Penetrate the skin and pause
Pass needle to the hub into the liver
Direct needle 45o to table, toward head
Do not redirect – straight in, straight out
Core first, then add aspiration if needed X
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22. FNA/Biopsy of Liver Indirect Ultrasound Guidance
Notch between xyphoid and costal arch
Choose needle length sufficient to penetrate
falciform ligament (at least 1-1/2“)
*Quickly* squirt needle contents onto a slide
Prep, dry and stain as usual
Confirm that you have hepatocytes on the slide
Big purple cells – granular cytoplasm
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23. FNA/Biopsy of Spleen
Very low risk of bleeding for diffuse disease and solid tumors
Significant hemorrhage risk for cystic structures
Indirect ultrasound guidance often sufficient for diffuse disease
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24. FNA/Biopsy of Kidneys
Can do blindly by palpating the kidney with one hand and aspirating or biopsying the
caudal pole cortex with the other
Or ultrasound guided
freehand for diffuse disease
Penetrate renal capsule
Measure needle throw with calipers, to avoid renal artery, aorta and caudal vena cava
Deploy biopsy needle, remove biopsy needle, apply pressure
Harvest biopsy sample for histopathology and/or cytology
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25. Diane DeBruyn – Mission TX
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26. FNA/Biopsy of Prostate
If smallish masses cannot be accessed transabdominally, they can be accessed rectally using a Franzen needle for FNA
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27. FNA/Biopsy of Prostate
If smallish masses cannot be accessed transabdominally, they can be accessed rectally using a Franzen needle for FNA
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28. FNA of Bone Lesions I use an 18g needle, add aspiration if needed
Sedation or at least pain meds on board
normal bone cortex
metastatic bone lesion
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29. FNA of Lung Lesions
Difficult to differentiate collapsed lung from mass
Lung more wedge shaped, with “hepatized” pattern
Needle 19g or smaller - fewer complications
No FNA with needle only – attach syringe and maintain negative pressure to prevent pneumothorax
Extension set between needle & syringe (or butterfly)
Maintains negative pressure
Prevents trauma during aspiration
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30. FNA of Lung Lesions
Difficult to differentiate collapsed lung from mass
Lung more wedge shaped, with “hepatized” pattern
Linear probe best for this
Needle 19g or smaller - fewer complications
No FNA with needle only – maintain negative pressure to prevent pneumothorax
Extension set between needle & syringe (or butterfly)
Maintains negative pressure
Prevents trauma during aspiration
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31. Pitfalls of FNA & Biopsy
FNA/biopsy of adrenals & pancreas often non-diagnostic
Most helpful when ruling out neoplasia, or organ source of mid-abdominal mass
Characteristics of malignancy are
unreliable
Adrenals are highly vascular
and tend to bleed
Neuroendocrine cells in an
unusual location indicate
metastasis
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32. FNA & Biopsy Complications
Bleeding – watch for this with the US probe for 5 minutes after last stick (<1% hemorrhage risk)
If bleeding is a concern, stick to a smaller needle
Use Doppler to identify and avoid large vessels
Small amount of self limiting bleeding is no problem (5%)
Asymptomatic pneumothorax after lung FNA no problem
Rupture of fluid filled structure - problem
Gall bladder – bile peritonitis
Abscess or gut – sepsis
Urinary tract - uroabdomen
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33. FNA & Biopsy Complications
Seeding of neoplasia
Highest risk is with transitional cell carcinoma
Get informed consent prior to aspiration
Hematuria after kidney biopsy often resolves in a few days
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34. Summary
PowerPoint – Ultrasound Guided Fine Needle Aspirates and Biopsies
.pdf of PowerPoint – (1 and 6 slides per page)
Protek disposable needle guides
Oncura FNA Training Module

35. Thomas Nyland, John Mattoon, Eric Herrgesell, Erik Wisner
Acknowledgments
Robert Fulton
Chapter 8: Focused or COAST3 – Reproductive Focused Ultrasound Techniques for the Small Animal Practitioner Editor Greg Lisciandro
Thomas Nyland, John Mattoon, Eric Herrgesell, Erik Wisner
Chapter 3: Ultrasound Guided Biopsy Small Animal Diagnostic Ultrasound Editors Nyland and Mattoon – 3rd Edition 2014