HeNe Laser (633 nm)-Coupled Confocal Microscope Allows Simulating Magnetic Resonance Imaging/Computed Tomography Scan of the Brain and Eye: A Noninvasive Optical Approach Applicable to Small Laboratory Animals

Abstract

Magnetic resonance imaging (MRI) and computed tomography (CT) are noninvasive medical imaging techniques used for the detailed visualization of internal organs of the human body. Because CT uses X-rays for imaging, there is a risk of radiation exposure. In contrast, MRI uses radiowaves and magnetic fields for imaging; thus, there are no reported biological hazards. However, neither MRI nor CT is suitable as a noninvasive imaging tool applicable in small laboratory animals such as zebrafish embryos or larvae. The recently established micro-CT scanner is only suitable for scanning adult fish and a staining procedure is required for imaging. In addition, CT-based scanning is generally more suitable for skeletal imaging but not for visualization of soft tissues because of its lower contrast. In this study, we evaluated whether 633 nm HeNe laser-coupled confocal microscope allows simulating MRI/CT scan and imaging soft tissues such as brain and eye in zebrafish embryos/larvae. We show that the 633 nm HeNe laser can penetrate well into intact brain and eye of zebrafish. It represents a noninvasive imaging method with high resolution while not requiring contrast agents, enabling the detection of differential signals from normal and pathological organs such as brain and eye.

Neoplasia and Neoplasm-Associated Lesions in Laboratory Colonies of Zebrafish Emphasizing Key Infl uences of Diet and Aquaculture System Design

“…The immune system of zebrafish is fundamentally similar to that of humans, however the roles of innate and adaptive immunity in all stages of the tumorigenesis process have not yet been addressed in zebrafish. The zebrafish model can play a unique role in discovery of novel contrast agents for tumor imaging (Canaple et al, 2008; Ullmann et al, 2011; Spitsbergen et al, 2007; Zheng et al, 2011) as well as in development of innovative anticancer drugs and more effective delivery methods such as use of nanoparticles to deliver drug combinations in a tissue targeted fashion (Harfouche et al, 2009). …”

Zebrafish: A Multifaceted Tool for Chemical Biologists

“…This has led to a map of mass cell movement, and a new understanding of how these cell movements led to specification of different germ layers in the zebrafish embryo . Techniques such as optical tomography have also been used successfully to develop highly detailed fine maps of embryos and to visualize phenotypes in mutants. , Zheng and colleagues have been able to simulate magnetic resonance imaging (MRI) and CT scan of the brain and eye of zebrafish embryos and larvae in fine detail using a 633 nm laser …”

“…276,277 Zheng and colleagues have been able to simulate magnetic resonance imaging (MRI) and CT scan of the brain and eye of zebrafish embryos and larvae in fine detail using a 633 nm laser. 278 Zebrafish are completely transparent only until about 10 days or so of development. As the pigment cells spread and the skin thickens, they become less amenable to imaging experiments.…”