Elastography New imaging method which provides very high contrast between masses
and host tissue, by estimating the measure of visco-elastic properties of tissues.
Types: Ultrasound Elastography MR Elastography
Slide 3
•Elasticity Imaging looks at mechanical properties -Show relative tissue stiffness or
hardness -Different information than B-mode which shows backscatter information
-Provides further insight into potential pathology •Helps to differentiate hard from
soft lesions. •Differentiates cystic from solid lesions. Advantages of ultrasound in
Elastography: real-time imaging capabilities, very high resolution in motion estimation
(~1mm), simplicity, non-invasiveness, and relative low cost.
2. Page 1 of 19
Elastography: An additional tool for characterisation of
breast lesions
Poster No.: C-0427
Congress: ECR 2010
Type: Educational Exhibit
Topic: Breast
Authors: A. M. Makudamudi, A. Kanakarajan, B. Raghavan, J. Govindaraj;
Chennai/IN
Keywords: elastography, BI-RADS, spatial resolution
DOI: 10.1594/ecr2010/C-0427
Any information contained in this pdf file is automatically generated from digital material
submitted to EPOS by third parties in the form of scientific presentations. References
to any names, marks, products, or services of third parties or hypertext links to third-
party sites or information are provided solely as a convenience to you and do not in
any way constitute or imply ECR's endorsement, sponsorship or recommendation of the
third party, information, product or service. ECR is not responsible for the content of
these pages and does not make any representations regarding the content or accuracy
of material in this file.
As per copyright regulations, any unauthorised use of the material or parts thereof as
well as commercial reproduction or multiple distribution by any traditional or electronically
based reproduction/publication method ist strictly prohibited.
You agree to defend, indemnify, and hold ECR harmless from and against any and all
claims, damages, costs, and expenses, including attorneys' fees, arising from or related
to your use of these pages.
Please note: Links to movies, ppt slideshows and any other multimedia files are not
available in the pdf version of presentations.
www.myESR.org
3. Page 2 of 19
Learning objectives
Elastography New imaging method which provides very high contrast between masses
and host tissue, by estimating the measure of visco-elastic properties of tissues.
Types: Ultrasound Elastography MR Elastography
Slide 3
•Elasticity Imaging looks at mechanical properties -Show relative tissue stiffness or
hardness -Different information than B-mode which shows backscatter information
-Provides further insight into potential pathology •Helps to differentiate hard from
soft lesions. •Differentiates cystic from solid lesions. Advantages of ultrasound in
Elastography: real-time imaging capabilities, very high resolution in motion estimation
(~1mm), simplicity, non-invasiveness, and relative low cost.
Background
PRINCIPLE Slide 5 Palpation creates & senses strain. Elasticity is the physical
property of a material when it deforms under stress (e.g. external forces), but returns
to its original shape when the stress is removed. Stress is the force causing the
deformation. Strain is the amount of deformation produced by the stress. Young's
modulus (E) describes tensile elasticity as the tendency of an object to deform along
the axis of compression It is a measure of the stiffness of an elastic material. Therefore
easily deformable substances will have low value of E and substances which are
difficult to deform will have high values Ultrasound Elastography Slide 6 •The
strain is estimated from minute differences between two B-mode images, during
compression either by the transmitted pulsation in cardiac cycle or by minimal active
probe compression. •The differences are in the order of 0.1 to 0.2 mm •Strain values
are then displayed as an image. •Image is displayed using either different shades of
gray or using different colours to represent the varying magnitude of strain values.
•Elastogram is superimposed on B-mode image. •Stiffer lesions appear darker & larger.
Technique of Image Acquisition •Probe and lesion perpendicular to gravity •Motion
is provided by the patient's breathing and heart beat •If insufficient, slow minimal
compression with the probe is applied Fig 5 Methods of computation of
tissue elasticity [1] 1.Spatial correlation method 2.Phase-shift tracking method
3.Combined autocorrelation method Spatial correlation method [1] •Uses an
ordinary two-dimensional pattern matching algorithm •Searches for the position that
maximizes the cross correlation between ROI's selected from two images obtained
before and after deformation. •This method can be used to demonstrate displacement
in two dimensions - longitudinal and lateral. Disadvantage : Processing time is
4. Page 3 of 19
lengthy for real-time assessment. COLOR MAPPING -ELASTICITY SCORE (Spatial
correlation method) Fig 1
Elasticity Score Fig 2
Slide 12 Fig 3 CYST - variable appearances
(Spatial correlation method) [2]
• 3-layered pattern with both bright and dark regions
• darker (stiffer) area with a brighter (softer) center, "bull's eye"
• a uniformly dark area
• Ill-defined margins
• Smaller or same size
Fig 4 Phase-shift tracking method [1] Based on autocorrelation method- principle
of color Doppler US. This method can be used to rapidly and precisely determine
longitudinal tissue motion because of phase-domain processing. Disadvantage:
•Errors related to aliasing - fails when used to measure large displacements. •Poorly
compensates for movement in the lateral direction - disadvantage for freehand
compression. Slide 15 •Slightly different technique is used in acquisition & computation
•B-mode image is obtained & ROI is placed within it •Lesion is actively compressed &
released for 3-5 times and frozen. •Elastography is computed by pressing Elastography
Q button. •Elasticity value obtained from the strain graph Fig 6 Slide 16 Fig 7 Slide 17
Fig 8
Images for this section:
Fig. 1: Color mapping- Elasticity score (Spatial correlation method)
14. Page 13 of 19
Fig. 7: Irregular small lesions
Fig. 8: Bilateral & Multifocal malignancy
15. Page 14 of 19
Fig. 9: Elastography in microcalcifications
16. Page 15 of 19
Conclusion
<</p>
Statistics Slide 27
Total no. of lesions studied- 100 (Spatial correlation method) Kappa agreement shows
elastography correlates better with pathology when compared to USG. Specificity
of elastography is better than ultrasound and correlates with literature. [3] Fig 1,
Fig 2, Fig 3 •Elastography provides additional information not otherwise available.
•Complementary to B-mode USG/ mammography. •Can reduce the indications for
unnecessary biopsies & interventions in benign lesions like complex cysts & in some
instances MRI. •Can help in guiding the appropriate area for biopsy (hard area)
•Quantitative analysis can be performed. •Increases confidence level. •Cost effective.
Images for this section:
Fig. 1: Statistics
17. Page 16 of 19
Fig. 2: Statistics- Kappa agreement
19. Page 18 of 19
Personal Information
Presenters:
Dr.Anugayathri Makudamudi
Resident in Radiology
Dr.Bagyam Raghavan
Senior Consultant
docbagyam@gmail.com
Department of Radiology & Imaging Sciences,
Apollo Speciality Hospital,
Chennai, India.
Acknowledgements:
Dr.S.Suresh,
Mediscan Systems,
Chennai, India.
References
References < 1.Ako Itoh, Ei Ueno, Eriko Tohno, Hiroshi Kamma, et al. Breast Disease:
Clinical Application of US Elastography for Diagnosis. Radiology: May 2006; 239:
341-350. 2.Tardivon A, et al. Elastosonography ofthe breast: prospective study of
122 lesions. J Radiol 2007;88:657-662. 3.Thomas A, Fischer T, Frey H, Ohlinger,
et al. Real-time elastography- an advanced method of ultrasound: first results in
108 patients with breast lesions. Ultrasound Obstet Gynecol 2006; 28: 335-340.
4.Garra BS, Cespedes EI, Ophir J, et al. Elastography of breast lesions: initial clinical
results. Radiology 1997;202:79-86. 5.Shiina T, Nitta N, Ueno E, Bamber JC. Real
time tissue elasticity imaging using the combined autocorrelation method. J Med
20. Page 19 of 19
Ultrason 2002;29:119-128. 6.ZhiH, et al. Comparison of ultrasound Elastography,
mammography, and sonography in the diagnosis of solid breast lesions. J Uìtrasound
Med 2007; 26:807-815.