Development of ultrasound tomography for breast imaging: Technical assessment

Abstract

Ultrasound imaging is widely used in medicine because of its benign characteristics and real-time capabilities. Physics theory suggests that the application of tomographic techniques may allow ultrasound imaging to reach its full potential as a diagnostic tool allowing it to compete with other tomographic modalities such as x-ray computer tomography, and MRI. This paper describes the construction and use of a prototype tomographic scanner and reports on the feasibility of implementing tomographic theory in practice and the potential of ultrasound (US) tomography in diagnostic imaging. Data were collected with the prototype by scanning two types of phantoms and a cadaveric breast. A specialized suite of algorithms was developed and utilized to construct images of reflectivity and sound speed from the phantom data. The basic results can be summarized as follows. (i) A fast, clinically relevant US tomography scanner can be built using existing technology. (ii) The spatial resolution, deduced from images of reflectivity, is 0.4 mm. The demonstrated 10 cm depth-of-field is superior to that of conventional ultrasound and the image contrast is improved through the reduction of speckle noise and overall lowering of the noise floor. (iii) Images of acoustic properties such as sound speed suggest that it is possible to measure variations in the sound speed of 5 m/s. An apparent correlation with x-ray attenuation suggests that the sound speed can be used to discriminate between various types of soft tissue. (iv) Ultrasound tomography has the potential to improve diagnostic imaging in relation to breast cancer detection.

Ultrasonographic Evaluation of Hyoid–Larynx Approximation in Dysphagic Stroke Patients

“…Examples include the work of Carson et a1 (1981), Andre et al (1997), Johnson et al (1999), Marmarelis et al (2002), Liu and Waag (1997), Duric et al ( 2005Duric et al ( , 2007. Chang et al (2007) also applied limited-angle UCT to clinical breast radio-frequency (RF) signals collected by conventional B-mode ultrasound machine.…”

Refraction corrected transmission ultrasound computed tomography for application in breast imaging

“…This shortcoming can be overcome by replacing ͑or augmenting͒ reflective by transmission ultrasound followed by tomographic reconstruction. Beginning with the seminal work of Greenleaf,7 several research groups have attempted this 3,[8][9][10][11][12] with promising results. Their methods can be dis-tinguished by the framework employed for modeling the propagation of sound in the heterogeneous medium that makes up the female breast.…”

An improved automatic time-of-flight picker for medical ultrasound tomography

“…(a) Schematic illustration of a ring transducer array (from [5]). (b) Interaction of an ultrasound pulse with a target leads to a scattered ultrasound field (from [17]). Tx = transmitter; Rx = receiver.…”

“…CURE is capable of recording all ultrasound wavefields including reflected, transmitted, and diffracted ultrasonic signals from the breast tissue. The engineering prototype of CURE is described in [17], and the current clinical prototype is described in [5]. Fig.…”