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1064 Biopsy, Ultrasound-Guided Percutaneous

hand can also be used for pulling food or Alternatives and Their Relative gained from referral to a veterinary behavioral
bones from the dog safely. Merits specialist.
VetBooks.ir Postprocedure ers, but there is no quality assurance. Herbal AUTHOR: Katherine A. Houpt, VMD, PhD, DACVB
Behavior problems can be referred to train-
EDITORS: Leah A. Cohn, DVM, PhD, DACVIM; Mark S.
remedies also lack quality control or controlled
Re-check in 3 and 6 weeks to determine the
Thompson, DVM, DABVP
success of the treatment and compliance of
behavioral issue, the more benefit there is to be
the owner. studies of their efficacy. The more serious the

Biopsy, Ultrasound-Guided Percutaneous

Difficulty level: ♦♦ • Sector or linear-array ultrasound transducer • Sample the caudal cortex of a kidney to avoid
○ Sector transducers allow sampling of deep the medulla and arcuate and hilar vessels.
Synonyms structures. • Do not pass through an organ other than
Tissue core biopsy, Tru-Cut biopsy ○ Linear-array transducers provide better the one being sampled.
resolution of superficial structures. • Avoid using preanesthetic drugs that cause
Overview and Goal • ± Biopsy guide: easiest method but angle of splenomegaly or panting (acepromazine/
Procedure to obtain tissue core sample using needle insertion fixed phenothiazines or hydromorphone/opiates,
ultrasound guidance and real-time monitoring • Anesthesia: intravenous (IV) or gas anesthesia respectively) whenever possible.
of needle instrument placement usually required. Depending on the size and
location of the lesion, light sedation and Procedure
Indications local anesthesia may be adequate. • Restrain the animal in dorsal or lateral
• Ultrasonographic detection of focal mass recumbency. A padded U- or V-shaped
lesion Anticipated Time trough can be used.
• Physical, ultrasonographic, or biochemical The procedure time is 10-15 minutes plus • Clip hair from the ventral abdomen.
detection of diffuse or focal parenchymal anesthesia preparation/recovery time. • Thoroughly evaluate area of interest sono-
organ abnormalities graphically, characterize lesion, identify
Preparation: Important adjacent or internal vessels to be avoided,
Contraindications Checkpoints and determine least traumatic location and
• Cavitated mass or bleeding disorder: risk of • Perform coagulation profile and platelet direction of needle placement.
hemorrhage count. • Prepare skin with surgical scrub.
• If abscess possible: risk of leakage, sepsis • Place IV catheter. • Obtain ultrasound image of area to be
• Intrathoracic masses not in contact with the • Ensure proper function of biopsy instrument. sampled with area of interest in focal zone
chest wall: poor visualization of image.
• Diffuse lung disease: risk of pneumothorax Possible Complications and • Ensure that probe marker location on screen
(p. 797) Common Errors to Avoid corresponds with desired needle course.
• Avoid overly rapid advancement and activa- • Prepare biopsy instrument.
Equipment, Anesthesia tion of the instrument. • Make a small skin incision with a scalpel
• Biopsy instrument: typically 14- to 18-gauge ○ A common, serious error of inexperienced blade at the site needle will be introduced.
needle veterinarians is to advance and activate • Introduce needle parallel to plane of
○ Automatic (biopsy gun using disposable the instrument in one motion, which is ultrasound beam, visualizing it as it is
needle) contraindicated (poor placement/control advanced.
Manually advanced to a point 1.5-2 cm of instrument tip). • Slowly fan transducer side to side to identify
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superficial to lesion ○ The full extent of the instrument must needle as necessary.
When triggered, cutting needle and be observed and monitored carefully and • Automatic instrument
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external shaft automatically advance a advanced with caution to the area to be ○ Note the throw length of the biopsy device
specific distance. sampled. before triggering it. This is the additional
○ Semiautomatic (disposable, safest, most • Identify and avoid large vessels in the organ distance the instrument advances when
commonly used) being sampled or in those adjacent to the triggered.
Inner cutting needle manually advanced structure to minimize hemorrhage. ○ Manually advance the needle, stopping at
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to desired depth • Avoid penetrating bowel lumen, especially this distance superficial to desired biopsy
When triggered, external shaft auto- with larger-gauge instruments, because of site. CAUTION: When triggered, needle
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matically advances over cutting needle. risk of peritonitis. will advance the full predetermined throw
○ Manual • Ensure that the ultrasound beam captures the length to obtain biopsy.
Operator controls depth of needle and full length and orientation of the instrument ○ Trigger needle: cutting needle and external
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length of tissue sampled. in the animal (p. 1112). shaft will advance the predetermined
Requires two hands to operate device • Sample the left aspect of the liver when pos- throw length to obtain sample.
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• Formalin container and cassette sible to avoid the gallbladder and hilar vessels • Semiautomatic instrument
• A #11 scalpel blade to incise skin on the right. If the liver is small or cranially ○ Manually advance the inner cutting needle
• A set of 25-gauge standard injection needles located, consider a caudal intercostal approach. to desired biopsy depth.
or a 3-mL syringe filled with saline • In cases of bilateral renal abnormalities, the ○ Trigger needle: external shaft will auto-
• Hair clippers left kidney should be sampled because of its matically advance over cutting needle to
• Surgical scrub, rubbing alcohol more caudal location. obtain sample.
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