Development of concurrent magnetic resonance imaging and volumetric optoacoustic tomography: A phantom feasibility study

Abstract

Optoacoustic tomography (OAT) and magnetic resonance imaging (MRI) provide highly complementary capabilities for anatomical and functional imaging of living organisms. Herein, we investigate on the feasibility of combining both modalities to render concurrent images. This was achieved by introducing a specifically‐designed copper‐shielded spherical ultrasound array into a preclinical MRI scanner. Phantom experiments revealed that the OAT probe caused minimal distortion in the MRI images, while synchronization of the laser and the MRI pulse sequence enabled defining artifact‐free acquisition windows for OAT. Good dynamic OAT contrast from superparamagnetic iron oxide nanoparticles, a commonly used agent for MRI contrast enhancement, was also observed. The hybrid OAT‐MRI system thus provides an excellent platform for cross‐validating functional readings of both modalities. Overall, this initial study serves to establish the technical feasibility of developing a hybrid OAT‐MRI system for biomedical research.

Multimodal Contrast Agents for Optoacoustic Brain Imaging in Small Animals

“…Co-registration and post-processing of small-animal neuroimage datasets acquired sequentially using OA imaging and other modalities have been performed for the region/volume of interest analysis ( Attia et al, 2016 ; Ren et al, 2019 ). For this, manual/semi-automatic atlas–based analysis and algorithms have been developed ( Ren et al, 2019 ; Ren et al, 2021 ; Zhang et al, 2021b ). Further studies to develop a deep learning–based method for fully automatic segmentation and registration are needed, for example, between OA/MRI or OA/CT brain imaging data and for position-dependent light fluence correction hold great promise ( Sarah et al, 2019 ; Waterhouse et al, 2019 ; Ni et al, 2020a ; Dean-Ben et al, 2020 ; Hu et al, 2021 ).…”

“…Further studies to develop a deep learning–based method for fully automatic segmentation and registration are needed, for example, between OA/MRI or OA/CT brain imaging data and for position-dependent light fluence correction hold great promise ( Sarah et al, 2019 ; Waterhouse et al, 2019 ; Ni et al, 2020a ; Dean-Ben et al, 2020 ; Hu et al, 2021 ). Additionally, bimodal animal holder ( Gehrung et al, 2020 ; Zhang et al, 2021b ) or concurrent imaging acquisition OA tomography–MRI, OA–fluorescence confocal microscopy, and OA tomography–fluorescence imaging have already been developed ( Chen et al, 2017 ; Zhang et al, 2018b ; Liu et al, 2019b ; Ren et al, 2021 ; Zhang et al, 2021c ; Dadkhah and Jiao, 2021 ; Deán-Ben et al, 2021 ). Further development in synchronized OA-MR platforms for small-animal brain imaging for simultaneous detection will further improve the workflow ( Ren et al, 2021 ).…”

“…Additionally, bimodal animal holder ( Gehrung et al, 2020 ; Zhang et al, 2021b ) or concurrent imaging acquisition OA tomography–MRI, OA–fluorescence confocal microscopy, and OA tomography–fluorescence imaging have already been developed ( Chen et al, 2017 ; Zhang et al, 2018b ; Liu et al, 2019b ; Ren et al, 2021 ; Zhang et al, 2021c ; Dadkhah and Jiao, 2021 ; Deán-Ben et al, 2021 ). Further development in synchronized OA-MR platforms for small-animal brain imaging for simultaneous detection will further improve the workflow ( Ren et al, 2021 ). 2) Modeling of pharmacokinetics: One compartment fluence independent model has been reported for OA imaging in the tumor tissue of the animal model ( Hupple et al, 2018 ).…”

Multi-scale optoacoustic molecular imaging of brain diseases

“…To this end, co-registration of images acquired by stand-alone MSOT and MRI scanners has been performed using MRI data as an anatomical reference for brain regional analysis [ 142 ] or by applying MRI/MSOT dual modality probes [ 86 , 100 , 162 , 163 ]. The recent introduction of a hybrid scanner capable of concurrent MRI and volumetric MSOT recordings [ 164 ] holds great promise for improving the workflow, further complementing and validating functional and molecular readings by both modalities. All in all, various other multimodal combinations have been reported in the context of molecular imaging of brain diseases, including fluorescence/MSOT [ 107 , 165 ], Raman/MSOT/MRI [ 84 , 91 ], MSOT/MRI [ 64 , 144 ], PET/MSOT [ 100 ], SPECT/MSOT [ 66 ], PET/MSOT [ 100 ], ultrasound/MSOT [ 166 , 167 ], and fluorescence molecular tomography (FMT)/CT/MSOT [ 86 ] (Fig.…”

In vivo co-registered hybrid-contrast imaging by successive photoacoustic tomography and magnetic resonance imaging

“…Co-registration of abdomen PAT and MRI images of small animals using a customized single-use silicone MRI holder has been reported previously 34 , which realized the registration of soft tissue images for the first time. Most recently, a prove-of-concept concurrent PAT-MRI imaging system has been proposed with phantom-based feasibility validation 35 . Development of such system requires high cost for customized instrumentation, and sacrifices the flexibility of individual system.…”