Brief overview of strain elastography functioning, practical use in breast elastography, interpretation of breast elastogram.

1. Strain Elastography
Implication in Breast Lesions
AQIB UMAIR
UIRSMITUIRSMIT
The University of Lahore

2. Strain Elastography
Strain elastography is a qualitative technique
and provides information on the relative
stiffness between one tissue and another.
1. Strain Elastography - How To Do It? Ultrasound Int Open 2017; 03(04): E137-E149. DOI: 10.1055/s-0043-119412

3. Inducing a distortion
Strain elastograms are generated by
rhythmic motion of the ultrasound transducer
or with physiological patient motion (breathing
&heartbeat).
Real-time feedback regarding appropriateReal-time feedback regarding appropriate
amount of stress being applied.
Displacement too large and too small cause poor
elastogram.
Footplate extenders can improve the
uniformity of the applied stress and
maximize the depth of stress penetration.

4. Magnitude of strain can be shown in these ways
Gray Scale Elastogram
Dark as stiff & Bright as soft.
Elastogram Presentation
Don’t super impose
Color Elastogram
Blue as stiff & Red as soft,
OR vice versa.
Careful investigation of displayed color bar
for correct interpretation of the elastogram.
Displayed superimposed

5. Apply probe lightly on the skin surface over the lesion
during a breath-hold.
The pressure & compression frequency on
indicating bar 2 to 3 during examination.
How Perform: Breast Strain Elastography
indicating bar 2 to 3 during examination.
Keep hands vertical with minimal compression,
to produce a high-quality SE image.

6. Center ROI box on the target lesion.
AP ROI should extend from the subcutaneous fat tissue to
the pectoralis muscle, excluding the thoracic cage.
In width, Keep lesion of interest within 25% of the ROI width
adequately including its surrounding areas.
How Perform: Breast Strain Elastography
In the case of a large lesion, the ROI can be placed
towards edge of the lesion, so that surrounding
normal tissue is included in the evaluation.

7. After a scan aquisition, show final Elastograms in gray sale or color.
To assess the quality of obtained elastogram,
freeze the image and review the stored cine loop frame by
frame. A consistent color pattern in consecutive frames
indicates a good reliable technique.
How Perform: Breast Strain Elastography
indicates a good reliable technique.

8. After acquiring an elastogram,
3 main diagnostic methods to classify lesions:
1. Tsukuba Score classification (Visual analysis of the
Interpretation: Breast Strain Elastography
1. Tsukuba Score classification (Visual analysis of the
color pattern)
2. Semi-quantitative strain ratio
3. Width ratio or EI/B ratio.

9. 1. Tsukuba score
A five points color scale, visual assessment of the color pattern of breast
lesion stiffness.
Lesions with a higher Tsukuba score have a higher probability of malignancy.
Interpretation: Breast Strain Elastography

10. 2. Strain ratio (semi quantitative)
Assuming the stress is uniformly distributed throughout the field of view.
The strain in the region of interest (ROI) can be compared to
a ROI in the reference tissue that is experiencing a similar stress.
Interpretation: Breast Strain Elastography

11. 2. Strain ratio (semi quantitative)
First, an ROI inside of the lesion (A) is selected
Secondly, the reference area (B) is selected in surrounding fatty tissue.
Strain ratio (B/A) = mean strain of fat (B) / mean strain in lesion (A)
Interpretation: Breast Strain Elastography
Strain ratio > 4.5 is suggestive of a malignancy.

12. 3. EI/B (Elastography /Bmode ratio)
Malignant lesions appear larger on elastograms than on B-mode images.
Measure lesion diameter on both the B-mode image and elastogram
allows calculation of the width ratio or EI/B ratio.
Interpretation: Breast Strain Elastography
EI/B ratio of < 1.0 for benign lesions and ≥ 1.0 for malignant lesions.