Download stereotactic breast biopsy

STEREOTACTIC BREAST BIOPSY
Smriti Hari
Associate Professor of Radiology
All India Institute of Medical Sciences
New Delhi
Percutaneous Breast Biopsy
 Ultrasound guided biopsy
 Mammographic (Stereotactic) biopsy
 MRI guided biopsy
 Modality selection depends on
 Visibility of the lesion
 Operator preference
Principle of Stereotactic Imaging
Stereotactic imaging - Requirements
 Stereo pair
 Reference point
 Computer
Scout image
Stereo Pair
+ 15 degrees
- 15 degrees
Parallax- apparent shift of
the lesion
Scout (0 degree)
+ 15 degrees
- 15 degrees
Stereotactic Biopsy- Equipment
Add-on erect unit
 Advantages
 Cost
 Space
 Efficiency
 Disadvantages
 Access to some
calcifications limited
 Vasovagal episodes
Stereotactic Biopsy-Dedicated Prone
Table
 Advantages
 Improved access to
microcalcifications in all
locations
 Patient comfort
 Disadvantages
 Cost
 Space
 Efficiency
Stereotactic biopsy
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Careful mammographic interpretation
Planning the procedure
Informed consent
Performing the biopsy
Specimen radiography
Clip placement
Post procedural care
Assessment of histopathological concordance
Follow up imaging
Careful mammographic interpretation
 Is there an indication for biopsy
 BIRADS 4/5 lesions
 Selected BIRADS 3 lesions
 Is the lesion only visible in mammography
 Microcalcifications
 Subtle masses
 Architectural distortion
 Is the lesion amenable to stereotactic biopsy
Stereotactic biopsy- Limitations
 Very thin breast(< 3cm compressed
thickness)
 Lesions close to skin
 Subareolar lesions
 Posterior lesions
Planning the procedure
 What to target
 Target on the worse
looking calcifications
 What approach
 Shortest distance
from skin to lesion
 Informed consent
 Performing the biopsy
 Understanding the equipment
 Positioning
 Targetting
 Needle placement errors
 Acquiring samples
Hologic MultiCare Platinum and Atec Biopsy System
•360°Access
Caudo-Cranial
Lateral
Approach
Cranio
Caudal Approach
Approach
Reference Point
 Where 3 axes (x, y, & z) intersect at right
angles
00
0
-25
+25
50
Z axis
Positioning
Breast should be in the centre
of the hole
Only one breast otherwise loss
of lateral tissue
Before rotating C-arm, move breast
away from the breast platform to
avoid painful twisting
Positioning
 Pull in lateral breast
tissue
 Sweep in superior breast
tissue
 Stabilize with both hands
while bringing in the
compression paddle
Positioning
 There should be no gap
b/w the breast and breast
platform –loss of posterior
tissue
 Elevated inframammary
fold
Positioning
 Pt positioned with area
of interest in the Bx
window
 Be alert for pt motion
 Mark the corners of targeted
area
 Take scout image
Scout view – Straight On
 Reposition if the lesion is not imaged in the center of
the window
Targeted Inferior
Mulit-Pass
Targeted off the line
Targeted inferior
Scout view – Stereo Pair
Confirm reference point
Target the lesion
Transmit the target coordinates
Targeted Inferior
Stroke vs. Stroke Margin
The distance the probe moves forward
starting in the cocked position to the
fired position.
STROKE
The distance from the probe tip to the
detector/breast platform once fired.
STROKE MARGIN
STROKE MARGIN FORMULA
T
(compression thickness)
+12mm
(paddle thickness)
-Stroke (biopsy device)
-Pre-fire (Z value – pull back of instrument)
= Stroke Margin
Stroke and Stroke Margin
12 mm
Target
Detector
or Breast
Platform
Compression Plate
Compression Thickness
Stroke and Stroke Margin
Pre-Fire
12 mm
Target
Detector
or Breast
Platform
Compression Plate
Compression Thickness
Stroke and Stroke Margin
Post-Fire Pre-Fire
Stroke
Margin
Stroke
12 mm
Target
Detector
or Breast
Platform
Compression Plate
Compression Thickness
Stroke Margin should always be positive
Correcting Negative Stroke Margin
Pre-Fire
12 mm
Target
Compression Plate
Reposition
from
opposite
angle
Compression Thickness
Detector
or Breast
Platform
Correcting Negative Stroke Margin
Pre-Fire
Post-Fire
12 mm
Target
Detector
or Breast
Platform
Compression Plate
Compression Thickness
Correcting Negative Stroke Margin
Original Adjusted
Pre-Fire Pre-Fire
-2 e.g., -4
12 mm
Target
Detector
or Breast
Platform
Don’t dial in
as far for
Pre-Fire
Compression Thickness
Compression Plate
Correcting Negative Stroke Margin
Post-Fire
Pre-Fire
12 mm
Target
Detector
or Breast
Platform
Compression Plate
Compression Thickness
SHORT CUT FORMULA
FOR
STROKE MARGIN CALCULATION
Z + (variable) must be less than
or equal to compression
Set up the biopsy device
 Disinfect the skin
 Attach the biopsy
device
 Move to Z position
 Align needle tip to
reference point
 Z-zero the needle
Vacuum assisted Biopsy Device
Needle insertion
 Move to target
 Move the needle close to
the skin
 Inject LA and make a skin
nick
 Advance the needle into
the breast using the Z dial
until the Z differential has
been met
 Take pre-fire images
 Evaluate needle position
Prefire images
Pre-fire Position
Pre-fire Pullback -2
x
-15
x
+15
Is the Needle in the Correct
Position?
•
Pre-fire & Post-fire Needle Position
–
–
–
–
Is the Needle Aligned to the Lesion?
Is the Needle in the Correct Position?
Has the Lesion Moved?
How Do I Correct the Situation?
How Do We Know We Have A
Needle Error ?
 Select view stage cursors to
determine lesion/patient movement
 Retarget if concerned about the
position of the lesion
X or Horizontal Error
Sampling should be increased
between 12 and 6 o’clock going
through 3 o’clock
X or Horizontal Error
Sampling should be increased
between 12 and 6 o’clock going
through 9 o’clock
Y or Vertical Error
Sampling should be increased
between 9 and 3 o’clock going
through 12 o’clock
Y or Vertical Error
Sampling should be increased
between 9 and 3 o’clock going
through 6 o’clock
Z or Depth Error
The depth must be increased by advancing the probe
Z or Depth Error
The depth must be decreased by pulling back the probe
 Fire the biopsy gun
 Take post-fire
images
 Evaluate needle
position
Post Fire
Post Exam
Post-fire Position
x
-15
x
+15
 Obtain multiple tissue cores
 Take post-biopsy stereo images
Specimen Radiography
 Confirms calcification
retrieval
 Caner can be missed, if
calcification is not
demonstrated*
 Miss rate 1% with retrieval
 11% without retrieval
 Recommended for US
guided biopsies also
*Radiology 2004;233:251-54
VAB: Marker Clip Deployment
 Deployed at the end of VAB
 If complete removal of lesion is
expected
 If biopsy diagnosis is cancer, metallic
clip facilitates hook wire localization
 Also recommended prior to
chemotherapy in LABC
 For any size of mass
Clip placement
Images for Documentation
 Scout (straight on)
 Scout (stereotactic pair)
 Pre-fire (stereotactic pair)
 Post-fire (stereotactic pair)
 Specimen radiograph
 Post clip placement
 Post procedure mammogram (two view)
Post Procedure
 Light compression at biopsy site (not
at the puncture site) for 10 minutes
 Patient to avoid strenuous ipsilateral
arm movements for 24 hours (lifting,
pushing)
 Observe for local bleed/ breast
enlargement
 Complications of breast biopsy are
rare
 Bleed, hematoma, infection
 Vasovagal attack
Misdiagnoses can be minimized
 Accuracy depends on showing representative
microcalcifications on specimen X-ray
 Histology must be correlated with imaging
 If biopsy results do not match expectation (imaging
histology discordance)
 Re-biopsy
 Malignancy in up to 33%*
 Surgical excision, if high risk lesion on biopsy
 Malignancy in up to 31%#
 Two years follow-up of benign biopsy results
*Breast Cancer Res Treat 2007;101:291-97
#Am J Surg 2006;192:534-37
Take Home Message
 Accurate and reliable breast biopsy can be
performed using stereotactic technique
 All biopsy results must be correlated with
imaging. If results are not concordant follow up!
 Radiologist should be responsible for
initiating, performing and auditing results of
image guided breast
Problem
lesions
 Lesions near the chest wall

Lesions near chest wall
 Pt relaxed
 Vigorous breast traction
and firm compression
 Arm through hole
 Helps with lateral lesions
 Remove the table pad
 Helps with medial lesions
Arm through hole with
special angled compression
paddle
Special Positioning
Techniques
Drop the shoulder in to view
axillary tissue
Superficial lesion
Pre-fire
Superficial lesion
Post-fire
Compression ~55 mm
Compression ~55 mm
Thin breast – petite needle
Pre-fire
Thin breast - petite needle
Post -fire
Compression
~25 mm
Compression
~25 mm
Bolstering to increase
compression thickness
Rolling towards breast platform
while applying compression
Easing the breast to bring in
posterior tissue
Release compression
slightly,pull breast platform
towrds th breast. It will relax
the posthe breast and allow
more posterior tissue to be
pulled in before recompression
is reapplied