Mammography Positioning Technique for Medio-Lateral (MLO) View

Mammography
Positioning Technique
for Medio-Lateral
(MLO) View
Ms Selin Prasad
Radiographer/Sonographer

ALARA Principle
• As Low As Reasonably Achievable (ALARA)
• Mammography uses low dose protocols in accordance with ALARA,
however, all precaution should be taken not to take unnecessary
images/repeats
• Repeats should be kept to a very minimum and ONLY done if
absolutely necessary
• Repeat of an image should ONLY be done if it serves a diagnostic
purpose, will aid in final diagnosis

Standard Views/Projections in Mammography
Medio-lateral Oblique (MLO)
Cranio-caudal (CC)
Latero-medial (LM)

Basic Concepts/ Application of Positioning
• To bring the breast to it’s natural anatomical position ( nipple perpendicular to chest wall) to maximise visualisation of
entire breast anatomy and potential pathology and avoid superimposition of breast structures.
• The lateral and inferior portions of the breast are more mobile than the superior and medial portions. Therefore standard
views have been developed to maximize this mobility and pull as much breast tissue toward the more fixed borders and
onto the imaging device as is possible.
• All mammographic views are defined by the direction of the x-ray beam from the tube toward the detector. The
mediolateral oblique view (MLO) is the single best view to image the majority of the breast tissue.
• The upper inner portion of the breast is the least successfully included portion, and so the other standard mammographic
view, the craniocaudal (CC), should include as much medial tissue as is possible without excluding lateral tissue.
• To visualize the posterior and upper-outer quadrants of the breast. This is intrinsic to the anatomy of the breast, which
lies anterior to and follows the line of the obliquely coursing pectoral muscle. Positioning the breast parallel to this
oblique line, which is the natural course of the tissue, it is possible to demonstrate most of the glandular tissue

Anatomical Landmarks for Positioning and Image
Analysis
Perimeter
Pectoralis
PNL

Medio-Lateral (MLO) Projection
Nipple
Pectoralis
Fibroglandular tissue
IMA
Retromammary fat

Perimeter of the breast used for image analysis
A: Lateral
B: Inferior
C: Medial
D: Superior
E: Axillary Tail
•

Pectoralis used for positioning and image analysis

PNL Used for Image Analysis
PNL measurement of CC should be within 1cm of PNL measurement on
the MLO view

MLO Projection Aims
1. Complete visualization of breast
parenchyma
2. Visualization of axillary nodes; Wide
margin at the axilla

MLO Projection Aims
3. Visualization of pectoralis major muscle, preferably to the level of the posterior
nipple line (PNL)

MLO Projection Aims
4. Visualization retroglandular/retromammary
fat
5. Nipple in profile (arrow)

MLO Projection Aims
6. An open inframammary fold/angle (IMA) should be visible (arrow)
IMA is the angle of deflection where the breast tissue meets the chest wall
below the breast.

MLO Projection Aims
7. No skin folds should be superimposed on the breast tissue/absence of skin
folds

Criteria Summary for MLO
• Image receptor parallel to the pectoralis major ( typically between 45-60 degree angle and
extends into the axilla)
• ‘up and out’ manoeuvre, the breast is pulled up and away from the pectoralis muscle which
allows for optimal compression of the breast and avoids drooping of lower breast tissue
• High contrast and optimal resolution- dense areas well demonstrated and no skin burn-out
• Nipple in profile
• No patient motion/ blurry image
• Ideally pectoralis muscle to the level of posterior nipple line (PNL)
• Absence of artefacts
• Ideally inframammary angle (IMA) should be visualized
• Laterality(marker), patient ID, date of mammogram and name of imaging clinic should be
clearly visible on the mammogram
• Wide margin of pectoralis muscle at the axilla and convex anterior margin

Prerequisites for successful positioning
1a. The tube angle usually is 45 degrees but varies from 30-60
depending on the patient’s body habitus

1b. Turn the patient’s feet and body towards the
unit , at approximately 45 degrees to the chest
wall edge of the image receptor (IR)- Image A
• The patient should stand with her hips slightly
anterior to the lower end of the IR ( forward) –
Image C
If the hips are behind the image receptor, it will
be harder to pull lateral tissue into view-Image
B
• The patient should relax her shoulders and
upper torso
A
B C

1c. Be flexible, what works for one patient
might not work for the other. By ‘ adjusting’
the angle to the patient’s build, breast tissue
can be demonstrate as far as possible
• As a guideline, draw an imaginary line from
the patient’s shoulder to mid-sternum, angle
the gantry to parallel this line.

2a. The chest wall edge of the image
receptor must be parallel to the patient’s
pectoral muscle when the upper arm is
horizontal and both the shoulders are at the
same level
• At the proper image receptor level, most of
the axilla is visible with good presentation
and compression of the breast. The height
of the image receptor will directly affect
the level of the arm

2b. Raise the ipsilateral arm to shoulder level,
forming a right angle with the body. This will
determine the height of the image receptor,
which should position the AEC detector of the
unit just above the nipple
• The upper edge of the image receptor should
be at the level of the humerus, keeping the
shoulder at the same height

2c. Incorrect : the shoulders are NOT at the
same level and the image receptor is too LOW
• if too much of the shoulder and upper axilla
are under the compression paddle, it will
prohibit proper compression on the lower
portion of the breast.

2d. Incorrect: the shoulders are NOT at the
same level and the image receptor is too HIGH
• Raising the image receptor too high will
elevate the arm higher, stretching the pectoral
muscle and causing difficulty in pulling the
breast into view

2e. Incorrect: the shoulders are at the same level, however, the image
receptor is too LOW

3a. Bend the elbow and gently rest the patient’s
hand (rather than gripping), on the lower part
of the support bar/hand-rail. with her elbow
draped behind the gantry
. If the patient grips the handrail tightly,
creates tension in the pectoral muscle ,
inhibiting the positioning (pulls tissue out of
FOV) and compression process thus reduces the
amount of tissue that can be imaged

3b. Breast tissue may extend to the
midsagittal plane, indicated by the dark line-
A
• The corner of the IR should be placed just
posterior to the axilla –B
• If the corner of the IR is placed in the axilla,
posterior tissue may be lost. Otherwise
difficult to pull the breast into view, or miss
breast tissue- C
• If the image receptor is too high, posterior
and lateral tissue will be lost-D
A B
DC

3c. The ipsilateral arm should not entirely rest
along the top of the image receptor. Instead,
bend the elbow, rotating the triceps muscle
posteriorly and superiorly bringing the lateral
portion of the breast closer to the positioning
surface, resting only the upper arm on the
image receptor. The elbow should rest posterior
to the image receptor. This manoeuvre
minimizes the thickness of the upper breast
and axilla under compression and also
eliminates skin folds in the superior aspect of
the MLO image.
A B
C D

3f. With the lateral portion of the breast on the image
receptor, rotate the patient’s hips and shoulders
inward to include posterior tissue and the IMF- A&B
• Excluding the IMF may eliminate posterior breast
tissue from being visualized. The IMF should be in
the “open” position on the image, with no evidence of
creasing or wrinkles-C Rotating the patient inward
will also bring the superior, posterior breast tissue
into view.
• The upper proximal aspect of the compression paddle
will rest in the hollow between the humeral head
and the clavicle.
• The chest wall edge of the compression paddle will
touch the sternum. Continue to hold the breast
outward and upward at all times while applying
compression to ensure visualization of posterior
tissue and the IMF. This tactic will also properly
present the ductal structures, spreads parenchyma
and pulls pectoral muscle away from chest wall
A B
C

3e. If the breast is left to droop, the ductal structures
will not be properly separated, and the detection of
architectural distortion will be more difficult, if not
impossible. Leads to ‘camel nose’ appearance-See
image
• Straighten the anterior breast to flatten the tissue,
reducing structural overlap. Lower the compression
paddle, skimming the chest wall, just enough to
hold the posterior portion of the breast in place,
sliding the supporting hand anteriorly toward the
nipple, as the compression takes over holding the
breast in place.
• This will prevent the breast from drooping and hold
posterior tissue in view. The patient may have to
gently hold her other breast out of the way (without
pulling the ipsilateral breast from view) to avoid
superimposition.

3d. At some point during the final steps of positioning for
the MLO, check the posterior aspect of the breast.
• Run a hand between the patient’s back and the image
receptor to make certain that the skin is tight and that
no posterior tissue is folded or lost.
• Beware: the positioning may look ideal from the
anterior perspective despite exclusion of the
posterolateral tissue ( Image A- missing posterior
density)
A B

The Pectoral Muscle and the MLO View
A. Proper positioning: pectoral muscle is
thick at the axilla, has a convex anterior
border, and extends to the level of the
PNL.
B. Improper positioning, the muscle may be
triangular in shape OR
C. be parallel to the edge of the film OR
D. Have a concave anterior margin
E. In small number of women, pectoralis
minor is demonstrated as a triangular
density superimposing pectoralis major -
See image (arrow)
A B
C D
E

Summary of MLO Positioning
1. Choose the appropriate receptor size and compression
paddle. Angle the gantry to the appropriate obliquity.
2. The patient should stand with her hips slightly anterior to
the lower end of the image receptor.
3. Turn the patient’s feet and body toward the unit
4. The patient should relax her shoulders and upper torso,
but keeping her knees straight.
5. Raise the ipsilateral arm to shoulder level, forming a right
angle with the body; elevate the image receptor to this level.
6. Place one hand behind the ipsilateral shoulder and the
other posterolateral to the breast tissue.
7. Lift and pull the breast gently but firmly upward and
outward, bringing the lateral aspect of the breast to rest on
the image receptor.
8. The upper corner of the image receptor should rest slightly
posterior to the axilla.
9. Bend the elbow, rotating the triceps muscle posteriorly and
superiorly, which brings the lateral portion of the breast
closer to the image receptor; leave only the upper part of the
arm to rest on the image receptor.
10. With the lateral portion of the breast on the
image receptor, rotate the patient’s hips and
shoulders inward to include posterior tissue and
the IMA, allowing the superior edge of the
compression paddle to rest in the hollow between
the humeral head and clavicle.
11. Hold the breast upward and outward, turning
the patient’s hips in toward the positioning
surface, bringing the IMA into the open position.
12. Straighten the anterior breast to flatten the
tissue, reducing structural overlap.
13. Slowly lower the compression paddle,
skimming the chest wall surface, removing the
supporting hand as the compression takes over
holding the breast in position.

Summary of Positioning Technique

Criteria to Assess MLO Image
1. The breast should not appear to droop on the
image, although with some large-breasted
women, drooping is unavoidable. In these cases,
add a third projection of a latero-medial lateral
or mediolateral lateral to image anterior
structures.
2. The pectoral muscle should be visualized to
the nipple (posterior nipple line [PNL]. This may
not be possible on all patients; however, it should
be the rule rather than the exception. The
muscle should also be imaged as convex, rather
than concave or flat. A concave or flattened
muscle indicates lack of relaxation of the muscle,
an inappropriate angle of obliquity, inadequate
use of the mobile medial border, or allowing the
patient to lean back slightly
3. The IMF should be “open” rather than
falling on itself, indicating that the breast
is in the “up and out” position
4. breast between these two lines. It will
not be possible to include all the medial
tissue on the MLO projection on all
patients, but the CC projection covers this
portion of the breast well. However, the
lateral line should include the lateral and
posterior breast tissue. If not, demonstrate
this area of the breast with an extra view

Image Quality Assessment- PGMI Rating
PGMI (Perfect, Good, Moderate, Inadequate) is a method of evaluation of clinical image
quality in mammography to ensure the maintenance of a high standard of mammography
• Assessment is based on:
-all breast tissue imaged (fat tissue
visualized posterior to glandular tissue)
-correct image identification clearly
shown
-date of examination
-client identification—name and (number
and/or date of birth)
• Side (laterality) markers
• Positional (orientation) markers
• radiographer identification
• correct exposure according to workplace
requirements
• good compression
• correct processing
• absence of artefacts
• no skin folds
• symmetrical images

Additional(Uplift) View &Mosaic Imaging
• Extra view taken if the lower/inferior
section of the breast is missing on the
standard MLO view OR
• If adequate/optimal compression has not
been applied to the lower/inferior breast
tissue due to thick pectoralis muscle (
Note: check/adjust angulation and patient
position on standard MLO positioning to
avoid uplift view) OR
• Done if nipple is not in profile ( check if
nipple is in profile in CC view before doing
an uplift)
• Some women with large breasts may need
more than two views of each breast to
image all the breast tissue adequately in
the two standard projections. If the breast
is too large for the IR, it should be imaged
in a mosaic/tile pattern, using several
overlapping views

Problems and Solutions
Artefact
• Check : Patient’s
• Hair is behind ears or tied up
• Long/dangly earrings are removed
• Shoulders are relaxed back
• Chin is slightly raised
• Other breast is being held back
Skin Folds and Creases
• Ensure patient is not standing too close to the IR,
bending in from the waist will alter the position of
the ribs, smooth out the infra mammary angle and
this will eliminate creases behind the breast
• Perform a ‘sweep’ of breast tissue, in a downwards
motion, behind the breast, starting in the axilla
and coming out at the bottom of the breast, keep
your hand flat against the IR and your little finger
against the rib cage
• For slimmer patients, ensure the corner of the IR is
placed into the axilla at a steeper angle eg. 55-60°,
this will allow the pectoral muscle to lie flat on the
IR

Height of Image Receptor
• Ensure that the breast is not too high or
too low on the IR
• The breast tissue should be placed in
the centre of the IR to obtain maximum
comfort for the patient and allow
optimal pressure distribution over the
breast tissue.
• Correct height placement of the IR will
allow the patient to relax and flatten
the pectoral muscle
Folds in the Axilla
• As compression is applied smooth breast
in upwards motion
• Ask patient to lift the ipsilateral elbow
( side being imaged), before compression
is applied and allow the patient to relax
her arm once done

Inframammary folds/creases
• Check that skin folds are removed from behind the
ribs prior to compression force application (ask the
patient to push her hips back whilst you smooth out
any creases and then return back in again before the
breast is lifted and compressed)
• Check the entire breast is in contact with the IR to
avoid any air gaps. It may help to ask the patient to
bend their knee on the side being imaged
• Whilst applying compression force, keep the breast
uplifted with one hand and smooth the infra
mammary with the other
• When positioning the patient ask her to bend forward
from the waist and clear the infra mammary area
prior to placing the breast on the IR and positioning
the arm. This alters the position of the ribs
Missing IMF/ Posterior Breast Tissue
• Check that the patient is standing in
front of the IR (check position of feet)
and that the correct angle is being used
for that particular body habitus.
• Check if all the breast tissue has been
pulled properly? Use your hand to run
down behind the breast, once in
position, and pull through all breast
tissue

Missing top/superior breast tissue
• If the top of the breast is not imaged and
raising the tube does not help, then lower
the angle of the tube
Nipple not in profile
• The direction of the nipple will alert you
to what portion of the breast would not be
demonstrated : Hint he nipple points
toward the missing tissue
• Elevate the IMF a little higher
• If the nipple is facing you it is likely that
the client is positioned at the incorrect
angle and is facing too far forwards,
medially rotate the client towards the IR
slightly
• If the nipple facing inwards towards the
IR then probably not enough breast tissue
has been pulled through

Position of Feet
• Ensure the patient is standing in the
correct place with the feet and ribs in
front of the IR
• With your hand check that the bottom of
the ribs are in front and about a palms
width away from the IR before getting
the breast on the IR
• Slimmer clients can be stood closer to
the IR
• It is helpful to ask the patient to slightly
bend their knee on the side being
imaged; the hip will drop which will
bring more of the body into contact with
the IR
Too narrow/too wide pec muscle
Too Narrow:
• Check the height of the IR; too high and the muscle
will be stretched, tense and not wide enough
• Always ensure that the corner of the IR is placed to
the back of the axilla and the arm stretched across,
otherwise the pectoral muscle will be too narrow
• Ensure the breast is pulled through and the pectoral
muscle is flat on the IR with no gaps. Creases will
occur if the IR is too far back in the axilla
Too Wide:
Check the height of the IR, too low and too much
breast tissue
will be included around the axilla
• If the IR will be too far back in the axilla, this results
in too much breast tissue at the top and insufficient
pressure on the main part of the breast

Pec muscle not up to PNL
• Alter the angle of the tube to suit the
body shape going steeper when
necessary (55 – 60 degrees) for
prominent sternums, hollow axilla’s,
slimmer patients
• Use a lower angle 45° or even 40° for
clients with short pectoral muscles or
‘barrel shapes’, ‘larger breasts’.
HOWEVER: If
• too much pectoral angle is demonstrated
on a patient with wide, short pectoral
muscles consider increasing your tube
angle 50° to reduce the width of the
muscle
The retro-mammary space is not visualized
behind the parenchyma
• Move the breast from the lateral
edge medially
• Ensure the breast mound moves
freely in your grip
• Support the breast tissue from the
inferior border using you entire
hand
• Immobilize the breast tissue on the
IR in the ‘up & out’ position using
the edge of your hand to support the
pectoral axis along the sternum

Mammography Positioning Technique for Medio-Lateral (MLO) View

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