Dr. Hoagland and Dr. Hitt are affiliated with Massachusetts General Hospital, Boston, MA.
percutaneous core-needle breast biopsy is an indispensable tool for
radiologists who need to sample ultrasound-detected lesions that are
suspicious or highly suggestive of malignancy (Breast Imaging-Reporting
and Data System [BI-RADS®] category 4 and 5 lesions).1 When
performed correctly, this procedure is a relatively safe, minimally
invasive procedure with diagnostic accuracy comparable to open surgical
biopsy.2-6 Furthermore, core-needle biopsy is more accurate
than fine-needle aspiration and typically provides core samples of
sufficient quality to stain for markers, which can guide neoadjuvant
treatment options when malignant processes are discovered.7-9
For benign lesions, core-needle biopsy often allows patients to avoid
surgical biopsy, a more invasive, time-consuming, costly, and
anxiety-provoking procedure. Surgical biopsy is also technically more
difficult, has increased risk of complications and increased recovery
time and is more likely to have an unsatisfactory cosmetic result.3-5,10,11
If surgical excision is required after a core biopsy, surgical planning
is often altered by the biopsy results, increasing the probability that
definitive surgery is performed the first time.
attempting a breast biopsy, the radiologist should be familiar with
important aspects of the procedure. Some of these include choosing the
most appropriate biopsy device, optimal patient positioning, safe and
effective handling of the needle, and providing the patient with
post-biopsy care and instructions. This article presents a step-by-step
description of how the authors perform ultrasound-guided core-needle
breast biopsies safely, effectively, and efficiently at our institution.
Preparation, ultrasound, and positioning
the procedure, prior imaging pertinent to the case should be reviewed.
Informed consent should be obtained from the patient after discussing
the procedure’s risks, benefits, and alternatives. Risks we routinely
discuss include bleeding, infection, placement of tissue markers, and
the potential need for additional surgery due to discordant results. We
also discuss the risk of milk fistula with lactating women.
Additionally, we assess for any relevant allergies and whether the
patient could be pregnant (pertinent in regard to postprocedure
mammograms). Immediately before starting the procedure, we perform a
time-out involving all members of the medical team and the patient, in
adherence to the Joint Commission’s Universal Protocol for Preventing
Wrong Site, Wrong Procedure, and Wrong Person Surgery.12
biopsy tray should be assembled in a consistent way before each
procedure. This ensures the operator is able to quickly locate all
elements, while minimizing the risk of accidental needle sticks and
contamination (Figure 1). The operator should also detach the introducer
trocar from its cannula to ensure smooth separation and perform a test
deployment of the biopsy device to confirm proper function. This
provides an opportunity to demonstrate for the patient the sound
produced by deployment, reducing the risk of startling the patient at
the critical moment of obtaining the sample.
The patient should
be optimally positioned to maximize safety and ease of access to the
target lesion. This typically involves elevating and flattening the
breast. For targets in the outer breast, placing a foam wedge behind the
ipsilateral shoulder can be useful to oblique the patient and roll the
breast toward midline. The foam wedge is typically not employed for
lesions in the medial breast, save for occasionally placing it below the
contralateral shoulder to roll the breast away from the sternum and
contralateral breast. Having the patient abduct the ipsilateral arm over
her head, resting it on rolled towels for comfort, can reduce slack in
the breast. However, if there is not enough tissue around the lesion to
perform the biopsy safely, the arm may be lowered slightly to increase
breast thickness. Additionally, the fifth finger of the hand operating
the transducer can be used to grasp the breast tissue distal to the
anticipated approach of the biopsy device, pulling the tissue toward the
operator. This technique can move the target lesion closer to the
device, increase tissue bulk around the target, and stabilize mobile
lesions. However, take great care when implementing this technique to
ensure the fingers of the operator will not be in the line of fire of
the biopsy device. When positioning the patient, keep in mind that the
skin will need to be entered far enough from the transducer to easily
position the needle parallel to the chest wall and perpendicular to the
ultrasound beam. Keeping the needle oriented perpendicular to the beam
can substantially improve needle visibility by maximizing the number of
reflected echoes (Figure 5).
Before cleaning the site, obtain
images clearly documenting the target lesion and the location of any
nearby sensitive anatomy, such as the skin or pectoralis muscle. Employ
color Doppler to determine the position of any nearby large vessels.
Occasionally, it is helpful to mark the skin over the lesion, especially
when the lesion is difficult to delineate from surrounding breast
parenchyma. Accomplish this by tapping the skin adjacent to the
ultrasound probe, and marking the location where movement is observed
directly overlying the lesion. Preprocedure ultrasound and positioning
are vital to determining the optimal approach and the most appropriate
biopsy device to employ. These factors can substantially impact the
efficiency and safety of the procedure.
Many core-needle biopsy devices with variable needle gauges and lengths are available. We typically employ a 14-gauge Monopty®
device (Bard, Tempe, AZ) with a 10-cm needle. With the press of a
button, this single-use, disposable, spring-loaded automatic deployment
device obtains tissue samples by firing a stylet at high speed into the
target lesion, rapidly followed by the cutting cannula. The rapid-fire
throw of automatic deployment devices may aid in adequate penetration
and sampling of dense or mobile lesions. However, it is important to
remember that the device’s throw length (eg, 2.2 cm for the Monopty®
device) and the course of the throw cannot be predicted with absolute
precision. Therefore, before deploying an automated throw device, the
operator must ensure that sensitive structures, such as the skin, the
pectoralis muscle, and large vessels are not in the potential deployment
path of the device.
In situations where anatomy prohibits safe
automatic deployment, a device allowing for manual placement of the open
sample notch should be considered. In these situations, we employ a
14-gauge Achieve® biopsy device (Cardinal Health, Dublin, OH)
that can deploy the stylet independent of the cutting cannula. The
stylet can be deployed outside the patient, preventing damage to
sensitive anatomy adjacent to the lesion. After feeding the stylet
through the introducer, the open sample notch can easily be visualized
by ultrasound (Figure 2). This allows a high degree of precision for the
operator to manually verify and document placement of the sample notch
within the lesion or a particular portion of a lesion. The outer
cutting cannula is then deployed, rapidly advancing over the specimen in
the sample notch without changing the needle tip position.
vacuum-assisted core-needle biopsy devices use a vacuum to pull tissue
into the open sample aperture. These devices can rapidly acquire
multiple specimens from a single insertion, allowing for shorter
procedure time and reduced trauma. We employ the handheld Finesse®
Ultra Breast Biopsy System with either a 10-gauge or 14-gauge needle
(Bard, Murray Hill, NJ). Vacuum-assisted core biopsy devices are
particularly well-suited for small lesions that may be challenging to
precisely target with automatic deployment devices. When sampling a
small lesion, the needle is manually advanced posterior to the lesion.
The cutting cannula is then retracted, and the open sample notch is
rotated anteriorly to face the target lesion. This easily visualizes the
lesion in the sample notch and permits real-time sample monitoring.
Taking multiple samples with this method may entirely remove small
lesions, with the exclusion of possible microscopic residual.13 For
larger lesions, the needle of the vacuum-assisted device is placed
within the lesion and rotated between sample acquisitions. We typically
rotate at consecutive 2-hour interval clock positions to obtain 6
samples, though selective sampling from one area of the lesion can also
percutaneous core-needle breast biopsy is a clean procedure, although
not a strictly sterile one. To minimize risk of infection, we clean the
skin with povidone-iodine, cover the area with sterile drapes, and
employ a sterile transducer cover. We then inject local anesthetic
superficially with a 25-gauge needle, creating a subcutaneous wheel
where the skin will be entered. Lidocaine 1% is commonly utilized; this
can be buffered with sodium bicarbonate 8.4% in a 10% vol/vol solution
to aid transit of anesthetic into the nerve endings and decrease the
“burn” sensation experienced by the patient.14 We then
administer deeper local anesthetic under ultrasound guidance. We advance
the needle to the margin of the lesion and inject anesthetic while
drawing the needle back. This provides a “practice run” to simulate the
most appropriate angle of approach to the target while numbing along the
future path of the biopsy needle. Injecting local anesthetic can also
help to optimally position a lesion. If the lesion is too superficial or
too deep, injection can push the lesion away from the skin or chest
wall (Figure 3). However, for vague target lesions, take care not to
obscure the lesion with adjacent anesthetic.
Introducer and needle advancement
make a small skin incision at the entry site with a #11 blade scalpel
to aid in reapproximation of the defect during healing. The blade should
be inserted while oriented anteriorly to minimize the amount of
subcutaneous tissue lacerated; this may be important for target lesions
located near the skin or chest wall. At this point, a coaxial introducer
or the needle of the biopsy device can be inserted through the skin
incision. At our institution, we almost invariably use a coaxial
introducer, which allows multiple samples to be obtained from a single
precautious puncture while resulting in less trauma to surrounding
tissue. Additionally, a tough fascial layer may exist between the skin
entry site and the target lesion that can be traversed once with the
introducer to avoid having to cross this tough tissue multiple times
with the biopsy needle. This can be particularly helpful when manually
advancing a biopsy needle with the stylet extended from the supportive
cannula, as the thin sample notch of the stylet is relatively flexible
and may bend when encountering thicker facial tissues.
advancing the introducer, the shaft should be parallel to the chest wall
to improve visualization by the ultrasound beam and avoid striking the
pectoralis muscle (Figure 4). The transducer and introducer should not
be moved simultaneously. To help visualize the introducer needle, use
the “sliding technique.” This involves fixing the ultrasound transducer
over the lesion while making small sliding or sweeping motions with the
needle parallel to the chest wall until it is well-visualized
perpendicular to the ultrasound beam. Moving the transducer to locate
the needle would result in loss of visualization of the target, which
would then have to be relocalized.
Once the introducer is
positioned, the inner trocar is removed and the needle is inserted
through the cannula. When advancing the needle, the operator should
ensure its tip is visualized at all times to avoid inadvertently
damaging sensitive anatomic structures. If a large vessel has been
identified near the target, then advancing under color Doppler should be
considered. A low flow rate Doppler setting (eg, 4 cm/sec) is sensitive
for significant blood flow.15
Knowing the biopsy needle’s throw distance and dead space length (eg, 22 mm and 7 mm respectively for the Monopty®
device) is important. If the
lesion is large enough, the needle tip can be positioned at its margin
before being deployed. If the lesion is small, the tip should be
positioned far enough away to ensure the sample notch traverses the
lesion after deployment. Before firing the device, the length of the
needle in the field of view should be in plane with the ultrasound beam
to accurately predict where the tip will lie after deployment.
Additionally, the needle should be parallel with the underlying chest
wall to ensure the pectoralis muscle is not struck when the needle is
fired. The predeployment position of the needle should be documented
with an image labeled “pre-core” (Figure 5).
each deployment, an image documenting the postdeployment position of
the needle should be obtained, ideally demonstrating traversal of the
target lesion. To ensure the needle was not deflected by the lesion, at
least one image in the orthogonal plane should be obtained to document
the needle in cross-section within the lesion (Figure 6). Four or 5
high-quality core samples should be sufficient for high diagnostic
accuracy.16,17 Taking at least one sample with a portion of
specimen bridging the margin of the lesion can aid the pathologist in
characterizing the interface between the target lesion and surrounding
breast parenchyma (Figure 2). We often attempt to target multiple areas
of lesions that are large enough to permit this.
devices, each specimen must be removed and temporarily placed in a 0.9%
sodium chloride solution. We swirl the open sample notch in a
collection tube containing enough saline to submerge the notch. First
transferring the samples to saline prevents the needle from directly
contacting formaldehyde solution in the final specimen jar, thus
preventing introduction of formaldehyde into the breast. All samples can
be deposited together in the same solution. It is important for the
operator to evaluate each specimen in the sample notch and after placing
it in the collection tube to ensure adequate cores are obtained. Fatty
normal breast tissue tends to be yellow and will generally float in
saline. Pathologic tissue tends to be white and will generally sink.16
Of course, a single core will often contain both normal and pathologic
tissue. When the biopsy needle is not present in the breast, the
operator or assisting technologist can apply manual pressure to minimize
bleeding at the biopsy site. After all samples are obtained, the
specimen tube should be immediately capped to prevent loss of the
samples if the tube is accidentally overturned.
time a specimen is obtained and sent for pathologic or cytologic
analysis, a tissue marker, or clip, should be placed at the biopsy site.
The tissue marker documents sampling location for easy identification
and localization in case the results indicate surgical excision is
required. This is particularly important for diminutive lesions that may
be annihilated at biopsy or obscured by postbiopsy changes. Tissue
markers can save a lot of future aggravation and provide important
clinical insurance for the patient.
The angle of approach for the
tissue marker deployment device does not have to be parallel to the
chest wall, since a throw does not occur. However, the tip of the tissue
marker device is very sharp, and the shaft is longer than most biopsy
device needles. Thus, the operator must take care in positioning and
advancing the device to avoid entering the chest wall or other sensitive
anatomic structures. Before deploying a tissue marker, a predeployment
image should document the tip of the device at the site. After the
tissue marker is deployed, and the introducer and tissue marker device
have been removed from the breast, 2 orthogonal images should be
obtained documenting the marker position relative to the lesion (Figure 7).
remove the collection tube containing the specimens from the sterile
field and pour the specimens into a specimen jar containing 10%
formaldehyde solution. Of note, the few milliliters of saline are not of
sufficient volume to significantly dilute the formaldehyde solution. We
take care to ensure no samples remain in the saline collection tube
after transfer. The operator should ensure that the specimen jar is well
labeled, with the lid tightly
secured and accompanied by an accurate pathology requisition before
sending it to the pathology laboratory. Once the samples are secured and
remote from the biopsy tray, the sharps can be disposed of without
concern of inadvertently discarding the samples.
risks of hematoma formation, the assisting technologist should apply
pressure to the biopsy site for 10 min or longer until hemostasis is
achieved. The incision is then reapproximated with sterile bandage
strips. The patient is instructed to avoid strenuous activity,
equivalent to lifting a gallon of milk, with the ipsilateral arm for the
subsequent 2 days. Postprocedure pain is typically minimal and does not
require medication. If not contraindicated, we instruct our patients to
take over-the-counter acetaminophen for pain relief.
postprocedure mammogram with mediolateral and craniocaudal views of the
biopsied breast should be performed to document deployment and location
of the tissue marker and to determine whether the lesion sampled
correlates with mammography findings. Once the pathology results become
available, we dictate an addendum to the procedure report indicating
whether the results are concordant with imaging findings, and whether
follow-up imaging or surgical excision is indicated. Additionally, these
conclusions are directly communicated to the referring clinician.
percutaneous core-needle breast biopsy is an effective,
minimally-invasive means of sampling breast lesions identified by
ultrasound. This procedure is more accurate than fine-needle aspiration
and often allows patients to avoid more invasive surgical biopsy.
However, it is imperative that radiologists be familiar with the
important steps of this procedure before undertaking it. With the
optimal choice of biopsy device and a clear understanding of the
appropriate techniques presented in this article, ultrasound-guided
core-needle biopsy is an extremely safe, efficient, and highly accurate
method for diagnosing breast neoplasms.
- BI-RADS Committee. Breast Imaging Reporting and Data System Atlas. 4th ed. Reston,VA.: American College of Radiology; 2003.
- Crystal P, Koretz M, Shcharynsky S, et al. Accuracy of
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consecutive breast biopsies with at least two-year follow-up of benign
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- Schueller G, Jaromi S, Ponhold L, et al. US-guided 14-gauge
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- ACR Practice Guidelines for the Performance of Ultrasound Guided
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- Rotten D, Levaillant JM, Leridon H, et al. Ultrasonographically
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- Willems SM, van Deurzen CH, van Diest PJ. Diagnosis of breast
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- Brancato B, Crocetti E, Bianchi S, et al. Accuracy of needle biopsy
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- Liberman L, Feng TL, Dershaw DD, et al. US-guided core breast biopsy: Use and cost-effectiveness. Radiology. 1998;208:717-723.
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