Ultrasound-guidedUltrasound-guidedfine-needle aspirate and fine-needle aspirate and

biopsy techniquebiopsy technique

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IntroductionIntroduction

This presentation describes the methods to use as well as other factors to consider when performing an ultrasound-guided fine-needle aspirate (FNA) or core biopsy. The scanning planes used for FNA and core biopsy are the same. The technique varies somewhat, and the differences are demonstrated. Animation is used to demonstrate the aspirate/biopsy techniques. Please note that this animation will not run properly with older versions of PowerPoint or PowerPoint viewer.

DirectionsDirections

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Indications

Accuracy

Materials

Animal preparation

Ultrasound-guided FNA and biopsyUltrasound-guided FNA and biopsytechniquetechnique

Probe orientation

Superficial lesion

Deep lesionMethod

Screen orientation

References

Rock/slide the probe

Keep needle in plane of beam

Method details:

Reset (exit) program

IndicationsIndications

There are many indications for ultrasound-guided aspirates and biopsies as there are essentially no pathognomonic lesions in ultrasound. Most of the time a cytologic or histopathologic sample is needed to make a definitive diagnosis. Samples for cytology and histopathology may obtained with ultrasound-guided, laparoscopic and surgical procedures.

IndicationsIndicationsIcterus/liver enzyme elevation/elevated bile acidsSplenomegalyFocal nodules or masses anywhereRenal disease sometimes (i.e. renal dysplasia, renal masses, lymphosarcoma suspects)ProstatomegalyFree abdominal fluidCysts Lymphadenopathy

U/S guided FNA/biopsies generally not done on:Adrenal glandsTransitional cell carcinoma suspect massesChronic renal failure, glomerulonephritis

AccuracyAccuracy

Currently there is a lack of consensus about the accuracy of ultrasound-guided fine needle aspirates and biopsies compared to surgical or post mortem biopsy sample results. Some studies report high accuracy, others, low accuracy. The differential diagnosis and case presentation both should be considered when determining the best method of obtaining a cytology or histopathology sample.

Animal preparationAnimal preparation• Coagulation concerns:

• A physical examination should be done to assess evidence of a coagulopathy, and if one is suspected, no aspirate or biopsy is recommended.• The pre-biopsy hematocrit should be known.• At least a platelet count is recommended before a fine-needle aspirate is done.• Perform a buccal mucosal bleeding time if i.e. von Willebrand’s disease, or other disorders of primary coagulation are suspected.• A platelet count as well as coagulation profile (PT, aPTT and/or PIVKA) are recommended before a core biopsy is done.

• Sedation/brief anesthesia may be indicated.• Prepare a sterile field

Coagulation testsCoagulation tests

• PT = Prothrombin time• PTT = Partial thromboplastin time• PIVKA = Proteins induced by vitamin K antagonism

MaterialsMaterials

• Biopsy guide or not• 22-G 1.5 inch “cysto’ needle or 22-G 3.5 inch spinal needle is often used for fine-needle aspirates.

• Attach needle to extension set then syringe for easier handling

• 14-G to 18-G core biopsy needles • Bard® automatic biopsy needles

• One hand to trigger• Forward ‘throw” varies from 11 to 22 mm• Order from Sound Technologies or other distributors

MethodMethod

• Biopsy guide or freehand• Thickness of beam is 1-2 mm• Must keep needle in plane of beam (biopsy guide would do this for you)• Shortest distance/safest pathway• “Sewing-machine” motion for fine-needle ‘aspirates’• Stab incision in skin before doing a core biopsy• Sample preparation and evaluation:• Spray aspirates carefully on the slide• Smear gently, dry rapidly• View representative slide before submitting• Place core biopsy samples in cassette, pouch or lens paper• Pick pathologist carefully

Probe orientationProbe orientation

Reference marker correspondsto left side of screen

(see Screen Orientation

slide)

Probe

Skin

Schematic of the resulting ultrasound

image

Superficial “lesion” to biopsy

Deep “lesion” to biopsy

Reference marker

Near field

Far field

Opposite reference marker

Screen orientationScreen orientation

Rock and/or slide the probe Rock and/or slide the probe to line up the lesionto line up the lesion

to a “reachable” positionto a “reachable” position

Deep lesion needsto be lined up

toward the edge of the beam

Superficial lesioncan be toward the edge

or in the center of the beam

Keep needle in the same plane Keep needle in the same plane as the beamas the beam

See rotated views

Keep needle in the same plane as the beam:Keep needle in the same plane as the beam:Rotated views of the Rotated views of the

probe/beam/biopsy planeprobe/beam/biopsy plane

Needle is placed in the plane of the beam

Angle to use for a superficial lesion: Angle to use for a superficial lesion: Aim needle more perpendicular to beamAim needle more perpendicular to beam

FNA:

Core biopsy:

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion FNASuperficial lesion FNA

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Take biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Take biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Take biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Superficial lesion core biopsySuperficial lesion core biopsy

Angle to use for a deep lesion: Angle to use for a deep lesion:

Aim needle more parallel to beamAim needle more parallel to beam

FNA:

Core biopsy:

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion FNADeep lesion FNA

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Take biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Take biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Take biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

Deep lesion Deep lesion core biopsycore biopsy

ReferencesReferences

• Fife WD (2005) Abdominal ultrasound: Aspirations and biopsies, In Ettinger SJ, Feldman EC (eds), Textbook of Veterinary Internal Medicine, 6th edition, St. Louis, Elsevier Saunders, pp. 271-275.

• Nyland TG, Mattoon JS, Herrgesell EJ, Wisner ER (2002) Ultrasound-guided biopsy, In Nyland TG, Mattoon JS (eds), Small Animal Diagnostic Ultrasound, Philadelphia, WB Saunders, Co., pp. 30-48.