Aims and objectives
Breast cancer is the most common cancer in women.
Several different imaging techniques are available to assess tumorous breast lesions [1-4].
To date,
the mammography has been the reference standard to assess breast lesions [1].
However,
such ionizing radiation is prescribed for biannual screening of women only at high risk,
over 50 years old.
Ultrasound (US) is an attractive tool for breast assessment because it is widely available,
non-ionizing and inexpensive.
However,
conventional ultrasound images,which show the reflectivity and texture of tissue,
fail to differentiate...
Methods and materials
Ten women with biopsy-proven lesions (4 invasive ductal carcinoma,
5 fibroadenoma,
1 cyst; mean age 70 yrs) were examined with hand-held SoS-US using a commercial ultrasound system (SonixTouch,
Ultrasonix,
Richmond,
CA) (Fig.
1).
B-mode imaging was used for lesion localization (Fig.2a).
Hand-held SoS-US (Fig.
2b) uses a passive plexiglassreflector positioned opposite to the breast was used as a timing reference for the signals transmitted through the lesions [9-10].
Synthetic aperture data was acquired and average speed of sound (SoS) values across the lesions were measured....
Results
All lesions were measurable with B-mode and speed of sound (SoS).
SoS-US tumors were examined in <2 minutes; 10/10 measurements were successful.
Average lesion size visible in B-mode was 2.0 cm (SD: 0.7 cm).
Malignant lesions showed an average SoS increase of 3.0% (SD: 0.2%) with respect to the background glandular tissue,
while benign lesions showed a SoS increase of 0.8% (SD: 0.1%) (Fig.
3).
SoS ultrasound correctly classified all lesions with a cut-off value of 2.3%.
However,
both strain ratios (SR) and shear wave...
Conclusion
Hand-held speed-of-sound is a promising new ultrasound adjunct technology to differentiate between bening and malignant lesions.
Speed-of-sound (SoS) provides differenttissue biomechanical properties (Bulk Modulus) to conventional elastography (Strain,
Shear Modulus).
While all examinated lesions could be correctly classified with a single SoS threshold,
both strain ratios (SR) and shear wave velocity (SWV) failed to differentiate fibroadenoma from carcinoma.
Moreover,hand-heldSoS-US showed less dependency on breast compression than SWV,
and is therefore potentiallyless affected by non-linearity cofounders,
which are problematic in elastography [11].Therefore,
SoS-US may reduce operator...
References
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Ann.
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doi:10.7326/M15.2886.
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Wang LHV (2006) Photoacoustic imaging in biomedicine.
Review of Scientific Instruments (77):4-041101.
DOI:10.1063/1.2195024.
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Boetes C,
Burke W,
Harms S,
Leach MO et al.
(2007) American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography.
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[4] Cosgrove D,
Piscaglia F,
Bamber J,
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Correas...