Diagnostic ultrasound ( PDFDrive )

CHAPTER 21 The Breast 773
A
B
FIG. 21.18 Importance of Light Pressure for Color Doppler Examination. (A) Micropapillary ductal carcinoma in situ lesion appears exceedingly
hypervascular when scanned with light pressure. (B) Lesion appears avascular when just the weight of the scanning arm is allowed to rest on the
transducer during scanning.
A
B
FIG. 21.19 Elastography Depicts Benign and Malignant Masses. (A) A benign-appearing hypoechoic macrolobulated mass has a strain value,
which is similar to the strain value of the surrounding tissue. The ratio is therefore close to 1. (B) An irregular, spiculated, not parallel mass has a
lower strain value as compared with surrounding tissue, consistent with malignancy. (Courtesy of Sughra Raza, MD.)
typically indicates increased stifness and increased likelihood
of malignancy and blue indicates less stifness and increased
likelihood of benignity, these color conventions have not been
standardized. Elastography features including shape, size,
heterogeneity, and stifness all complement the features obtained
during routine diagnostic ultrasound imaging. Quantitative values
have also been advocated for improved standardization. Studies
have shown that elastography can be helpful to improve speciicity
of diagnostic imaging and to identify more advanced
malignancies. 26-29
Limitations of elastography primarily relate to the lack of
standardization of technique and implementation across vendors.
Grading schemes, 30,31 quantiication of signal, 28 and color-coding
of lesions vary. 24,27 In addition, these techniques are based on
compression, which can vary by user and, in turn, can afect
elasticity measures.
Three-Dimensional Ultrasound
hree-dimensional (3-D) ultrasound captures volumetric information
about breast lesions so they can be viewed in sagittal, coronal,
and transverse planes. his is being studied with both hand-held
and automated breast ultrasound methods to determine its added
value above conventional ultrasound. Initially, 3-D ultrasound
was not shown to be superior to conventional ultrasound 32,33 ;
however, more recent studies suggest that 3-D ultrasound may
help with identifying cancer. 34
Contrast-Enhanced Ultrasound
New vascular networks are created as malignant tumors grow.
Doppler ultrasound is currently used to capture these areas of
neovascularity. However, Doppler has not been shown to be
suiciently accurate in its ability to diferentiate malignant from
benign masses. As a result, contrast-enhanced ultrasound has