Elastography: An Additional Tool for Characterisation of Breast Lesions

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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.

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Elastography: An Additional Tool for Characterisation of Breast Lesions

  1. 1. Elastography:AnAdditionalToolfor CharacterisationofBreastLesions
  2. 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. 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. 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)
  5. 5. Page 4 of 19 Fig. 2: Elasticity score
  6. 6. Page 5 of 19 Fig. 3: Elasticity score
  7. 7. Page 6 of 19 Fig. 4: Cyst-variable appearances (Spatial correlation method) Fig. 5: Technique of Image acquisition
  8. 8. Page 7 of 19 Fig. 6: Phase shift tracking method Fig. 7: Elastographic computation in Phase tracking method
  9. 9. Page 8 of 19 Fig. 8: Phase tracking method- graphical display
  10. 10. Page 9 of 19 Imaging findings OR Procedure details Cystic lesions Fig 1 Cystic & complex cystic lesions Fig 2 Cystic & complex cystic lesions Fig 3 Discordant Elastogram in benign lesions Fig 4 Solid rounded lesions Fig 5 Solid rounded lesions Fig 6 Irregular small lesions Fig 7 Slide 25 Fig 8 Slide 26 Fig 9 Images for this section: Fig. 1: Cystic lesions
  11. 11. Page 10 of 19 Fig. 2: Cystic & complex cystic lesions
  12. 12. Page 11 of 19 Fig. 3: Cystic & complex cystic lesions Fig. 4: Discordant Elastogram in benign lesions
  13. 13. Page 12 of 19 Fig. 5: Solid rounded lesions Fig. 6: Solid rounded lesions
  14. 14. Page 13 of 19 Fig. 7: Irregular small lesions Fig. 8: Bilateral & Multifocal malignancy
  15. 15. Page 14 of 19 Fig. 9: Elastography in microcalcifications
  16. 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. 17. Page 16 of 19 Fig. 2: Statistics- Kappa agreement
  18. 18. Page 17 of 19 Fig. 3: Statistics- Sensitivity & Specificity
  19. 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. 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.
  21. 21. Apollohospitals:http://www.apollohospitals.com/ Twitter:https://twitter.com/HospitalsApollo Youtube:http://www.youtube.com/apollohospitalsindia Facebook:http://www.facebook.com/TheApolloHospitals Slideshare:http://www.slideshare.net/Apollo_Hospitals Linkedin:http://www.linkedin.com/company/apollo-hospitals Blog:Blog:http://www.letstalkhealth.in/

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