multimodality; elastography; quantitative medical imaging; clutter reduction; sound speed; aberration correction
Petrosyan Tigran, Theodorou Maria, Bamber Jeff, Frenz Martin, Jaeger Michael (2018), Rapid scanning wide-field clutter elimination in epi-optoacoustic imaging using comb LOVIT, in Photoacoustics
, 10, 20-30.
Singh Mithun Kuniyil Ajith, Jaeger Michael, Frenz Martin, Steenbergen Wiendelt (2017), Photoacoustic reflection artifact reduction using photoacoustic-guided focused ultrasound: comparison between plane-wave and element-by-element synthetic backpropagation approach, in Biomedical Optics Express
, 8(4), 2245-2245.
Preisser Stefan, Held Gerrit, Akarçay Hidayet G, Jaeger Michael, Frenz Martin (2016), Study of clutter origin in in-vivo epi-optoacoustic imaging of human forearms, in Journal of Optics
, 18(9), 094003-094003.
Held K. Gerrit, Jaeger Michael, Rička Jaro, Frenz Martin, Akarçay H. Günhan (2016), Multiple irradiation sensing of the optical effective attenuation coefficient for spectral correction in handheld OA imaging, in Photoacoustics
, 4(2), 70-80.
Held K. Gerrit, Jaeger Michael, Frenz Martin, Akarçay H. Günhan (2016), Spectral correction of OA signals based on multiple irradiation sensing: experimental validation, in SPIE BiOS
, San Francisco, California, United StatesSPIE , Bellingham.
Jaeger Michael, Held Gerrit, Peeters Sara, Preisser Stefan, Grünig Michael, Frenz Martin (2015), Computed Ultrasound Tomography in Echo Mode for Imaging Speed of Sound Using Pulse-Echo Sonography: Proof of Principle, in Ultrasound in Medicine and Biology
, 41(1), 235-250.
Jaeger Michael, Robinson Elise, Akarcay H. Guenhan, Frenz Martin (2015), Full correction for spatially distributed speed-of-sound in echo ultrasound based on measuring aberration delays via transmit beam steering, in PHYSICS IN MEDICINE AND BIOLOGY
, 60(11), 4497-4515.
Jaeger Michael, Frenz Martin (2015), Towards clinical computed ultrasound tomography in echo-mode: Dynamic range artefact reduction, in Ultrasonics
, 62, 299-304.
Jaeger Michael, Held Gerrit, Preisser Stefan, Peeters Sara, Grünig Michael, Frenz Martin (2014), Computed Ultrasound Tomography in Echo mode (CUTE) of speed of sound for diagnosis and for aberration correction in pulse-echo sonography, in Ultrasonic imaging and tomography
, SPIE, Bellingham.
Jaeger Michael, Gashi Kujtim, Peeters Sara, Held Gerrit, Preisser Stefan, Gruenig Michael, Frenz Martin (2014), Increase of penetration depth in real-time clinical epi-optoacoustic imaging: Clutter reduction and aberration correction, in Photons plus ultrasound: Imaging and sensing
, SPIE, Bellingham.
Preisser Stefan, Held Gerrit, Peeters Sara, Jaeger Michael, Frenz Martin (2014), Influence of illumination position on image contrast in epi-optoacoustic imaging of human volunteers, in Photons plus Ultrasound: Imaging and sensing
, SPIE, Bellingham.
Jaeger Michael, Gashi Kujtim, Akarçay Hidayet Günhan, Held Gerrit, Peeters Sara, Petrosyan Tigran, Preisser Stefan, Gruenig Michael, Frenz Martin (2014), Real-time clinical clutter reduction in combined epi-optoacoustic and ultrasound imaging, in Photonics and Lasers in Medicine
, 3(4), 343-349.
Jaeger Michael, Gashi Kujtim, Peeters Sara, Held Gerrit, Preisser Stefan, Frenz Martin (2014), Real-time clutter reduction in epi-optoacoustic imaging of human volunteers, in Ultrasonic imaging and tomography
, SPIE, Bellingham.
Held Gerrit, Preisser Stefan, Günhan Akarçay H., Peeters Sara, Frenz Martin, Jaeger Michael (2013), Effect of irradiation distance on image contrast in epi-optoacoustic imaging of human volunteers, in Biomedical Optics Express
, 5(11), 3765-3780.
Modern society’s ageing population and growing health problems require beyond-state-of-the-art facilities for early disease detection and personalized medicine, and it is growingly perceived that multimodal imaging is the key to more accurate diagnosis and patient-tailored therapy. Among the various established medical imaging modalities, ultrasound (US) is comparably low-cost, non-ionizing, and provides the patient short, comfortable sessions. Real-time and free-hand operation makes it easy to quickly access different parts of the body. At the downside conventional US as a single contrast modality provides limited differential diagnosis, often making subsequent use of CT/MRI mandatory. Optoacoustic imaging (OA) is an emerging technique which can complement classical US with additional functional information for multimodal imaging. The tissue is irradiated using pulsed laser light, and conversion of absorbed laser light to ultrasound theoretically allows the detection of optically absorbing structures deep inside the tissue with ultrasound resolution. This is promising for imaging vasculature and oxygenation status of tissue based on the absorption spectra of oxy- and deoxyhaemoglobin. Recent years have seen a rapid development of OA techniques, and we and various research groups have investigated combined OA and US imaging. A remaining challenge, however, to successful combination of OA with US, still is to obtain a clinically useful imaging depth. We were the first to identify strong signal clutter to be the main limiting factor to OA imaging depth, and during our running NF project we developed displacement-compensated averaging (DCA) for OA clutter reduction. DCA was based on clutter decorrelation that naturally occurs when palpating the tissue and thus facilitates clutter reduction via averaging. Our results have demonstrated that OA clutter reduction is feasible using specialized scanning techniques in conjunction with sophisticated data processing. DCA, however, shows several disadvantages at the clinical application level, including a rather low contrast gain of only a factor of 2 to 3, limited applicability to only palpable tissue, and a requirement for special skills in probe guidance. Therefore we want to develop within the proposed project a novel clutter reduction technique which in theory allows complete clutter cancellation without the need for palpation or any special skills. This technique will be based on localized vibration tagging (LOVIT) of the OA signal at its place of origin using a focused ultrasound beam, which allows the unambiguous identification of true OA signal within the clutter background. First phantom results confirmed the great potential of our invention which will be a break-through for deep clinical OA. Within the proposed project we will investigate and optimize this technique towards future in-vivo applications, and we will also use the same method for a concluding investigation of the origin of clutter in real tissue. In addition to that we will investigate the combination with radiation force elastography with which it shares the same technical background. This continues our multimodal imaging approach that we already adopted for the running project, and complements our portfolio with a new elastography technique. In addition to clutter, we identified inhomogeneous speed of sound in tissue as a further important limitation to deep imaging. Inhomogeneous sound speed leads to ultrasound aberrations and thus to degraded resolution and contrast if not properly accounted for, making aberration correction a requirement for deep OA imaging! Aberration correction is currently based on a blind auto-focusing approach, which has limited applicability in OA. Within the framework of the proposed project we want to go an entirely new way, taking advantage of a combined OA and US system. We hypothesize that in such a combined device, accurate OA aberration correction beyond the state-of-the-art is feasible when based on an independent measurement of sound speed using US. We recently invented a method which allows measuring sound speed spatially resolved with high resolution using echo US, and we will investigate this method to provide an accurate input to direct aberration correction in OA. In addition to that we will investigate sound speed as additional imaging modality in its own right, augmenting the diagnostic accuracy of a multimodal device. In summary our basic research will yield novel beyond the state-of-the-art developments towards multimodal imaging using US as a real-time, save, and versatile device for improved quantitative diagnostic accuracy at low cost. This project will strongly benefit from two PhD students which will ensure the smooth accomplishment of the parallel project parts. In addition to that, the purchase of a VerasonicsTM ultrasound research scanner will facilitate the planned fundamental research with high efficiency, because it provides outstanding research access for the direct implementation of the special scan sequences and data processing schemes that will be developed during the proposed project.