scholarly journals Ultrasound and Photoacoustic Imaging of Laser-Activated Phase-Change Perfluorocarbon Nanodroplets

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 405
Author(s):  
Heechul Yoon
Keyword(s):  
Phase Change ◽  
Photoacoustic Imaging ◽  
Super Resolution ◽  
Optical Pulses ◽  
Future Directions ◽  
Therapeutic Drugs ◽  
Contrast Enhanced ◽  
Resolution Imaging ◽  
Optical Activation ◽  
Micrometer Size

Laser-activated perfluorocarbon nanodroplets (PFCnDs) are emerging phase-change contrast agents that showed promising potential in ultrasound and photoacoustic (US/PA) imaging. Unlike monophase gaseous microbubbles, PFCnDs shift their state from liquid to gas via optical activation and can provide high US/PA contrast on demand. Depending on the choice of perfluorocarbon core, the vaporization and condensation dynamics of the PFCnDs are controllable. Therefore, these configurable properties of activation and deactivation of PFCnDs are employed to enable various imaging approaches, including contrast-enhanced imaging and super-resolution imaging. In addition, synchronous application of both acoustic and optical pulses showed a promising outcome vaporizing PFCnDs with lower activation thresholds. Furthermore, due to their sub-micrometer size, PFCnDs can be used for molecular imaging of extravascular tissue. PFCnDs can also be an effective therapeutic tool. As PFCnDs can carry therapeutic drugs or other particles, they can be used for drug delivery, as well as photothermal and photodynamic therapies. Blood barrier opening for neurological applications was recently demonstrated with optically-triggered PFCnDs. This paper specifically focuses on the activation and deactivation properties of laser-activated PFCnDs and associated US/PA imaging approaches, and briefly discusses their theranostic potential and future directions.

scholarly journals Autoencoder based blind source separation for photoacoustic resolution enhancement

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Matan Benyamin ◽  
Hadar Genish ◽  
Ran Califa ◽  
Lauren Wolbromsky ◽  
Michal Ganani ◽  
...  
Keyword(s):  
Photoacoustic Imaging ◽  
Resolution Enhancement ◽  
Super Resolution ◽  
Optical Excitation ◽  
Biological Tissues ◽  
General Idea ◽  
Acoustic Response ◽  
Depth Imaging ◽  
Resolution Imaging ◽  
Novel Concept

AbstractPhotoacoustics is a promising technique for in-depth imaging of biological tissues. However, the lateral resolution of photoacoustic imaging is limited by size of the optical excitation spot, and therefore by light diffraction and scattering. Several super-resolution approaches, among which methods based on localization of labels and particles, have been suggested, presenting promising but limited solutions. This work demonstrates a novel concept for extended-resolution imaging based on separation and localization of multiple sub-pixel absorbers, each characterized by a distinct acoustic response. Sparse autoencoder algorithm is used to blindly decompose the acoustic signal into its various sources and resolve sub-pixel features. This method can be used independently or as a combination with other super-resolution techniques to gain further resolution enhancement and may also be extended to other imaging schemes. In this paper, the general idea is presented in details and experimentally demonstrated.

scholarly journals Molecular Imaging of Tau Protein: New Insights and Future Directions

2020 ◽  
Vol 13 ◽  
Author(s):  
Rocco Pizzarelli ◽  
Natalia Pediconi ◽  
Silvia Di Angelantonio
Keyword(s):  
Near Infrared ◽  
Clinical Symptoms ◽  
Super Resolution ◽  
Diagnostic Tools ◽  
Advanced Imaging ◽  
Future Directions ◽  
Cellular Processes ◽  
Functional Aspects ◽  
Resolution Imaging ◽  
Self Aggregation

Tau is a microtubule-associated protein (MAPT) that is highly expressed in neurons and implicated in several cellular processes. Tau misfolding and self-aggregation give rise to proteinaceous deposits known as neuro-fibrillary tangles. Tau tangles play a key role in the genesis of a group of diseases commonly referred to as tauopathies; notably, these aggregates start to form decades before any clinical symptoms manifest. Advanced imaging methodologies have clarified important structural and functional aspects of tau and could have a role as diagnostic tools in clinical research. In the present review, recent progresses in tau imaging will be discussed. We will focus mainly on super-resolution imaging methods and the development of near-infrared fluorescent probes.

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