USG guided biopsies

2. Introduction
 Fine needle aspiration (FNA) is a type of minimally-invasive tissue
sampling
 Ultrasound guided biopsy is one form of imaged guided biopsy, typically
performed by a radiologist.
 It is the most common form of image guided biopsy, offering
convenience and real time dynamic observation with echogenic markers on
cannula allowing for precise placement.
 Ultrasound-guided biopsy involves the removal of cells from a suspicious
area within the body using a thin needle and a syringe.
 It can potentially be used to perform a biopsy of any body part, being
regularly used to biopsy the kidney, liver, breast and lymph nodes.
 If the suspected tumor is in the deeper planes and cannot be seen or felt
by the physician, then the patient is asked to get an ultrasound-guided
biopsy.
 The sample of tissue or fluid then is evaluated in the laboratory to
determine your diagnosis.

3. Indications
 a suspicious solid mass
 a distortion in the structure of the viscera
 an area of abnormal tissue change
Applications currently include sampling cells in lesions from:
 thyroid
 non-thyroid neck
 breast
 liver
 lymph nodes
 lung
 bone
 gastrointestinal tract
 Mediastinum
 Pancreatic mass

4. Guidelines for Thyroid biopsy
high risk history
• with suspicious sonographic features: >5 mm
• without suspicious sonographic features: >5 mm
• with abnormal cervical lymph nodes: all; FNA may be obtained from the lymph
node as well
• with microcalcifications: ≥1 cm
solid nodule
• hypoechoeic: >1 cm
• solid nodule, iso or hyperechoeic: ≥1-1.5 cm
mixed cystic-solid nodule
• with suspicious sonographic features: ≥1.5-2 cm
• without suspicious sonographic features: ≥2 cm
spongiform nodule: ≥2 cm
purely cystic: FNA not indicated

5. Contraindications
 uncooperative patient
 lack of safe access
 uncorrectable bleeding diathesis (abnormal coagulation indices)
Laboratory parameters for a safe procedure
 Complete blood count: Platelet > 50000/mm3
 international normalized ratio (INR) ≤1.5 3
 normal prothrombin time (PT), partial thromboplastin time (PTT)
4/28/2024

6. Procedure
Preprocedural evaluation
 Patient consent and pre-procedure targeted physical exam
 A pre-procedure targeted ultrasound exam is commonly performed.
Equipment
 The "fine needle" in an FNA varies depending on the system being
biopsied and the nature of the lesion, but is typically a 22 gauge to 27
gauge needle with a stylet. For ultrasound-guided procedures, the
transducer may have a needle guide.
 Generally a 3.5 – 5 Mhz transducer is used for biopsy, however a
linear/superficial probe is useful in case of neck masses and breast lesions.
 1%/2% lidocaine without epinephrine
 Betadine and spirit swabs
 50cc and 20cc syringes
 10 glass slides with teasers for tissue separation

9. Positioning
 For most of the lesions as in case of liver, pancreas, GIT, neck etc., the
patient is positioned in supine or lateral decubitus position with
maximum access to the location of the lesion.
 For lung or pleural biopsy patient can be either made to sit upright of lie
down in lateral decubitus position .
 For FNA biopsy from breast, patient is positioned in the dorsal decubitus
as for a conventional breast ultrasound exam or in lateral decubitus as it
promotes a safer access to the lesion.
Probe Sterilization
The transducer must be sterilized before its use by betadine and spirit
swabbing. Ideally a layer of disposable plastic/condom should be placed
over it to achieve true sterilization.

10. Technique
The FNA technique will vary depending on the system being targeted
and the nature of the lesion. Techniques common to all procedures
include:
 local anesthesia with 2% buffered lidocaine
 Must keep needle in plane of beam (biopsy guide would do this for you)
 Shortest distance/safest pathway
 advancing the fine needle under imaging guidance until the tip is in the
intended area of biopsy
 removal of the stylet
 “Sewing-machine” motion for fine-needle ‘aspirates’ (filling the needle
with the tissue)
 removal of the needle with appropriate disposition of the cells (e.g. slide
for smear, container for cell block)
 multiple samples are usually obtained in a session
 Spray aspirates carefully on the slide
 Smear gently, dry rapidly

18. Postproceduralcare
 There is no standardized postprocedure care for FNA. Compression of the
biopsy site with gauze is common to control minor local bleeding.
 If the lung is biopsied, a post procedure radiograph may be obtained.
 In case of liver and pancreas biopsy, patient is made to lie in right lateral
and prone positions respectively.
 A minimum of three hours of bed rest is essential after any biopsy.
Complications
 Complications are uncommon with appropriate FNA technique, usually
limited to bleeding or infection. Bleeding is more of a concern with deeper
abdominal aspirations since direct pressure can rarely be applied.
 Pneumothorax is a risk of lung biopsies. Either a postprocedure
radiograph or ultrasound may be obtained to look for this complication.

19. Outcomes
 FNA success is measured in terms of aspirating a diagnostic amount of
tissue and maintaining patient comfort.
 Rates of success in aspirating diagnostic tissue depend on multiple factors,
not the least of which include the size of the needle being used, the
location of the lesion, and the type of lesion being biopsied. Larger bore
"fine" needles capture more tissue per aspiration and are more likely to
result in diagnostic tissue, but the benefits of minimally-invasive aspiration
diminish.
 If a fine needle aspiration does not return diagnostic material, it may be
repeated. Alternatively, if appropriate, a core biopsy may be attempted.
 Maintaining patient comfort depends on multiple factors including:
appropriate administration of local anesthesia, minimizing the number of
samples, and obtaining enough material to prevent having to call the

21. Advantages
• Better precision
• Increased chances of positive result
• Out-patient procedure; less burden on patient and physician
• Real time visualization of needle and guiding it to target lesion.
• Helpful in documentation
• Reach lesions situated in deeper planes
Pitfalls
• Failure to recognize the lesion
• Failure to direct the needle properly or visualize it
• Failure to prepare the slides properly