  Computed ultrasound tomography in echo mode (CUTE) is a new ultrasound
(US)-based medical imaging modality with promise for diagnosing various types
of disease based on the tissue's speed of sound (SoS). It is developed for
conventional pulse-echo US using handheld probes and can thus be implemented in
state-of-the-art medical US systems. One promising application is the
quantification of the liver fat fraction in fatty liver disease. So far, CUTE
was demonstrated using linear array probes where the imaging depth is
comparable to the aperture size. For liver imaging, however, convex probes are
preferred since they provide a larger penetration depth and a wider view angle
allowing to capture a large area of the liver. With the goal of liver imaging
in mind, we adapt CUTE to convex probes, with a special focus on discussing
strategies that make use of the convex geometry in order to make our
implementation computationally efficient. We then demonstrate in an abdominal
imaging phantom that accurate quantitative SoS using convex probes is feasible,
in spite of the smaller aperture size in relation to the image area compared to
linear arrays. A preliminary in vivo result of liver imaging confirms this
outcome, but also indicates that deep quantitative imaging in the real liver
can be more challenging, probably due to the increased complexity of the tissue
compared to phantoms.
