Plane Wave Pulse-Echo Ultrasound Diffraction Tomography With A Fixed Linear Transducer Array
Martin Schiffner, Georg Schmitz
Acoustical Imaging, vol. 31, 2012, pp. 19 - 30, DOI: 10.1007/978-94-007-2619-2_3 (The 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, Apr. 10-13, 2011.)
Ultrasound diffraction tomography (UDT) is a well-known high-quality imaging modality that has been investigated theoretically in numerous publications. However, most studies focus on a perfect reconstruction of the object to be imaged. The underlying Fourier diffraction theorem dictates that this goal requires transmission measurement data of the object for all angles. The resulting acquisition protocols thus either involve moving transducers, a large number of transducers located around the object to be imaged, or a rotating object. These prerequisites render the perfect reconstruction approach practically infeasible for most situations in clinical ultrasound imaging.
In this contribution we present a theoretical framework for UDT using a fixed linear transducer array and a fixed object. Within this framework, we employ broadband plane wave excitation and measure only backscattered ultrasound waves. We present an adapted version of the filtered backpropagation equation that allows the direct computation of the resulting image from measurement data. Using pulse-echo measurement data acquired by a commercial ultrasound imaging system from a wire phantom and a human vessel phantom, we validate our approach experimentally. We compare the quality of the resulting images to the quality achieved by conventional delay-and-sum beamforming procedures in terms of resolution and artefacts.
Our method eliminates the practical drawbacks of the perfect reconstruction approach presented in literature and yields a similar resolution as conventional delay-and-sum beamforming procedures whereas imaging artefacts are reduced. The approach can easily be extended to arbitrary excitation waveforms or point sources by employing plane wave decomposition.[Springer] [DOI]