Quantitative Photoacoustic Imaging: Measurement of Absolute Chromophore Concentrations for Physiological and Molecular Imaging

Cardiovascular Molecular Imaging

10.1093/med/9780199392094.003.0029 ◽

2015 ◽

Cited By ~ 1

Author(s):

Alan R. Morrison ◽

Joseph C. Wu ◽

Mehran M. Sadeghi

Keyword(s):

Molecular Imaging ◽

Photoacoustic Imaging ◽

Nuclear Imaging ◽

Biological Information ◽

Novel Approach ◽

Novel Therapeutic Strategies ◽

Pathologic Processes ◽

Cardiovascular Molecular Imaging ◽

Accurate Quantification

Cardiovascular molecular imaging is a relatively young but rapidly expanding discipline that consists of a biologically-targeted approach to the assessment of physiologic and pathologic processes in vivo. This novel approach to imaging involves the integration of multiple disciplines such as cell and molecular biology, chemistry, and imaging sciences. The ultimate goal is quantitative assessment of cardiovascular processes at the cellular and molecular level, moving beyond traditional diagnostic information, in order to guide individually tailored therapy. In fact, it is likely that specific approaches to molecular imaging will be developed in tandem with the development of novel therapeutic strategies. Recent advances in probe development and imaging systems have contributed to evolution of molecular imaging toward clinical translational. These include technological progress in traditional imaging platforms; along with the emergence of newer imaging modalities such as photoacoustic imaging. In addition, hybrid imaging (e.g. nuclear imaging with CT or MRI) has the potential for improved spatial localization, and more accurate quantification by coupling anatomic and biological information. In addition to potential clinical applications that address existing diagnostic gaps in cardiovascular medicine, molecular imaging allows for unique approaches to studying pathophysiology. This chapter is intended to provide an overview of the state of the art in cardiovascular molecular imaging, highlighting how it may improve the management of major cardiovascular diseases.

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Photoacoustic reporter genes for noninvasive molecular imaging and theranostics

Journal of Innovative Optical Health Sciences ◽

10.1142/s1793545820300050 ◽

2020 ◽

Vol 13 (03) ◽

pp. 2030005

Author(s):

Zhao Lei ◽

Yun Zeng ◽

Xiaofen Zhang ◽

Xiaoyong Wang ◽

Gang Liu

Keyword(s):

Molecular Imaging ◽

Fluorescent Proteins ◽

Photoacoustic Imaging ◽

High Sensitivity ◽

Reporter Genes ◽

Biological Processes ◽

Deep Tissue ◽

Potential Applications ◽

Improved Performance

Noninvasive molecular imaging makes the observation and comprehensive understanding of complex biological processes possible. Photoacoustic imaging (PAI) is a fast evolving hybrid imaging technology enabling in vivo imaging with high sensitivity and spatial resolution in deep tissue. Among the various probes developed for PAI, genetically encoded reporters attracted increasing attention of researchers, which provide improved performance by acquiring images of a PAI reporter gene’s expression driven by disease-specific enhancers/promoters. Here, we present a brief overview of recent studies about the existing photoacoustic reporter genes (RGs) for noninvasive molecular imaging, such as the pigment enzyme reporters, fluorescent proteins and chromoproteins, photoswitchable proteins, including their properties and potential applications in theranostics. Furthermore, the challenges that PAI RGs face when applied to the clinical studies are also examined.

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Light-Emitting-Diode-Based Multispectral Photoacoustic Computed Tomography System

Sensors ◽

10.3390/s19224861 ◽

2019 ◽

Vol 19 (22) ◽

pp. 4861 ◽

Cited By ~ 8

Author(s):

Sumit Agrawal ◽

Christopher Fadden ◽

Ajay Dangi ◽

Xinyi Yang ◽

Hussain Albahrani ◽

...

Keyword(s):

Computed Tomography ◽

Molecular Imaging ◽

Photoacoustic Imaging ◽

Light Emitting Diode ◽

Low Cost ◽

Tunable Laser ◽

Cost Effective ◽

Light Emitting ◽

Multi Wavelength ◽

Human Finger

Photoacoustic computed tomography (PACT) has been widely explored for non-ionizing functional and molecular imaging of humans and small animals. In order for light to penetrate deep inside tissue, a bulky and high-cost tunable laser is typically used. Light-emitting diodes (LEDs) have recently emerged as cost-effective and portable alternative illumination sources for photoacoustic imaging. In this study, we have developed a portable, low-cost, five-dimensional (x, y, z, t, λ ) PACT system using multi-wavelength LED excitation to enable similar functional and molecular imaging capabilities as standard tunable lasers. Four LED arrays and a linear ultrasound transducer detector array are housed in a hollow cylindrical geometry that rotates 360 degrees to allow multiple projections through the subject of interest placed inside the cylinder. The structural, functional, and molecular imaging capabilities of the LED–PACT system are validated using various tissue-mimicking phantom studies. The axial, lateral, and elevational resolutions of the system at 2.3 cm depth are estimated as 0.12 mm, 0.3 mm, and 2.1 mm, respectively. Spectrally unmixed photoacoustic contrasts from tubes filled with oxy- and deoxy-hemoglobin, indocyanine green, methylene blue, and melanin molecules demonstrate the multispectral molecular imaging capabilities of the system. Human-finger-mimicking phantoms made of a bone and blood tubes show structural and functional oxygen saturation imaging capabilities. Together, these results demonstrate the potential of the proposed LED-based, low-cost, portable PACT system for pre-clinical and clinical applications.

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Photoacoustic molecular imaging with functional nanoparticles

Journal of Innovative Optical Health Sciences ◽

10.1142/s179354581730004x ◽

2017 ◽

Vol 10 (04) ◽

pp. 1730004 ◽

Cited By ~ 3

Author(s):

Liming Liu ◽

Huan Qin

Keyword(s):

Molecular Imaging ◽

High Spatial Resolution ◽

Photoacoustic Imaging ◽

Imaging Modality ◽

Ultrasonic Waves ◽

Diffusion Limit ◽

Biological Processes ◽

Functional Nanoparticles ◽

Current Review ◽

Optical Nanoprobes

Photoacoustic imaging (PAI) breaks through the optical diffusion limit by making use of the PA effect. By converting incident photons into ultrasonic waves, PAI combines high contrast of optical imaging and high spatial resolution in depth tissue of ultrasound imaging in a single imaging modality. This imaging modality has now shown potential for molecular imaging, which enables visualization of biological processes with systemically introduced functional nanoparticles. In the current review, the potentials of different optical nanoprobes as PAI contrast agents were elucidated and discussed.

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Examining the technical feasibility of prostate cancer molecular imaging by transrectal photoacoustic tomography with transurethral illumination

Experimental Biology and Medicine ◽

10.1177/1535370219884356 ◽

2019 ◽

Vol 245 (4) ◽

pp. 313-320 ◽

Cited By ~ 1

Author(s):

Haonan Zhang ◽

Shengsong Huang ◽

Yingna Chen ◽

Weiya Xie ◽

Mengjiao Zhang ◽

...

Keyword(s):

Prostate Cancer ◽

Molecular Imaging ◽

Ex Vivo ◽

Photoacoustic Imaging ◽

Transrectal Ultrasound ◽

Human Prostate ◽

Light Illumination ◽

Light Emitting ◽

Non Invasive ◽

Urethral Wall

To pave the road toward clinical application of photoacoustic imaging in prostate cancer (PCa) diagnosis, we studied the technical feasibility and performance of transrectal photoacoustic (PA) imaging in mapping the indocyanine green (ICG) contrast agent, which is approved by FDA, in entire prostates by using light illumination via the urethral track. Experiments were conducted on a clinically relevant ex vivo model involving whole human prostates harvested from radical prostatectomy. The light source placed in the urethral track was an array of light emitting diodes (LEDs), illuminating the prostate with a delivered light power on the urethral wall within the safety limit. A dual-modality imaging system acquired PA and ultrasound (US) images simultaneously in the same way as in transrectal ultrasound (TRUS), with the US imaging presenting the tissue structure and PA imaging detecting the ICG solution. The imaging results demonstrated that tubes containing ICG solution at different concentrations can be detected at different positions in the prostate within a 2 cm range around from the urethral wall. Considering the sizes of regular human prostates, the proposed transurethral illumination in combination with transrectal US detection can facilitate PA molecular imaging over the entire prostate in a non-invasive manner, which makes it possible to further improve the PCa diagnosing efficiency with better molecular sensitivity and resulted better biopsy accuracy and much reduced pain for patients. Impact statement Differentiating cancerous tissues from healthy ones is critical in the diagnosis of prostate cancer (PCa). However, due to the low sensitivity of ultrasound (US) imaging to cancerous tissues, transrectal ultrasound (TRUS) guided biopsies, current standard procedure for diagnosing PCa, suffer from low core yield, leading to under-sampling and under-grading of clinically significant tumors. Via the experiment on the ex vivo human prostates, we evaluated the translational potential of photoacoustic imaging (PAI) based on a safe light emitting diodes (LED) source for detecting the molecular information in deep human prostate. We showed that transurethral light illumination in combination with transrectal US detection can facilitate PA molecular imaging over an entire human prostate in a non-invasive manner. The success of this study in the clinically relevant ex vivo human prostate model suggested a new strategy for PA and US combined imaging and detection of PCa.

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Recent Endeavors on Molecular Imaging for Mapping Metals in Biology

Biophysics Reports ◽

10.1007/s41048-020-00118-7 ◽

2020 ◽

Vol 6 (5) ◽

pp. 159-178

Author(s):

Jing Gao ◽

Yuncong Chen ◽

Zijian Guo ◽

Weijiang He

Keyword(s):

Molecular Imaging ◽

Transition Metals ◽

Photoacoustic Imaging ◽

Molecular Probes ◽

Future Research ◽

Non Invasive ◽

Dynamic Events ◽

Metal Sensors ◽

Health And Disease ◽

Future Research Directions

Abstract Transition metals such as zinc, copper and iron play vital roles in maintaining physiological functions and homeostasis of living systems. Molecular imaging, including two-photon imaging (TPI), bioluminescence imaging (BLI) and photoacoustic imaging (PAI), could act as non-invasive toolkits for capturing dynamic events in living cells, tissues and whole animals. Herein, we review the recent progress in the development of molecular probes for essential transition metals and their biological applications. We emphasize the contributions of metallostasis to health and disease, and discuss the future research directions about how to harness the great potential of metal sensors. Graphic Abstract

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