Optical Imaging for Tissue Assessment

While effective, many imaging technologies use ionizing radiation that can harm patients when used frequently. Entrenched radiological and nuclear imaging technologies, however, provide better image quality and higher spatial resolution than optical imaging, and its limited depth resolution hampers its deployment in tissue assessment. Read more about the latest technologies.

Physicians use X-ray, magnetic resonance imaging, and positron emission tomography to obtain high-resolution images of tissues without surgery. While effective, these imaging technologies use ionizing radiation that can harm patients when used frequently.

Because optical imaging technologies use the non-ionizing radiation corresponding to visible light, it eliminates this hazard. An additional benefit is that they offer a spread of colors that the other imaging technologies cannot.

Optical imaging systems used in health care represent the convergence of multiple technologies that Frost & Sullivan tracks, including advanced optical, infrared photoelectric, and complementary metal oxide semiconductor (CMOS) sensors; biosensors; and optical systems including light sources, collimators, lenses, mirrors and reflectors. Biomarkers, dyes and contrast agents from biochemical supply companies, and informatics systems from processing and analytics companies, also contribute.

Entrenched radiological and nuclear imaging technologies, however, provide better image quality and higher spatial resolution than optical imaging, and its limited depth resolution hampers its deployment in tissue assessment. Frost & Sullivan research has found technology developers who are addressing these limitations to make optical imaging more competitive.

Tufts University (Medford, Mass.)

Researchers at the university’s Fantini Lab are tackling the depth limitation by using diffuse optical imaging. This involves emitting near-infrared light from multiple projectors located around biological tissue and using near-infrared spectroscopy to measure the reflected light to create three-dimensional images of the target tissues. The Tufts team is developing novel near-infrared spectroscopy and imaging techniques for medical diagnostics for animal models and human subjects.

The focus includes functional imaging of the brain, assessment of cerebral microcirculation, diffuse optical mammography, hemodynamic monitoring of skeletal muscles, and quantitative tissue oximetry.

Tianjin Polytechnic University (Tianjin, China)

Near-infrared light spectroscopy is the optical tool that School of Electronics and Information Engineering researchers used to quickly pinpoint the location of any anomalies in tissue based on their optical density.  The team employed its Infrascanner to emit near-infrared light and capture the reflected light, and then used finite element analysis to measure the optical density of the horizontal positions, depths and diameters of anomalies. This device would provide physicians in emergency rooms and intensive care units with a relatively simple, accurate, cost-effective and portable method of detecting hematomas. Other potential applications for the Infrascanner include tumor detection and brain function imaging.

The University of Texas MD Anderson Cancer Center (Houston, Texas)

Optical imaging can aid pathology as well as diagnostics. A good example is the confocal fluorescence microscopy (CFM) platform that pathologists at the cancer center used to examine ex vivo tissue samples. CFM involves using an aperture to sharpen the view of a biological sample marked with a fluorescent dye illuminated by an excitation light.

The team immersed 55 breast, lung, kidney and liver surgical specimens in acridine orange and created images using a CFM platform operating at a 488-nanometer wavelength. The scientists obtained good-quality images that enabled them to recognize details comparable to those obtained by other conventional histology (tissue structure study) methods.  The images were obtained within five to 10 minutes—a fraction of the time that the other methods require.

Perimeter Medical Imaging Inc. (Toronto, Ontario)

Even faster than the cycle of the University of Texas optical imaging approach is that provided by Perimeter’s Optical Tissue Imaging System, known as OTIS. This intraoperative imaging tool gives surgeons, radiologists and pathologists the ability to review tissue microstructures in real time.

The company based OTIS on optical coherence tomography (OCT), which uses light waves to create three-dimensional images of tissues to depths of 1 to 2 millimeters in the patient’s body. OCT has proven itself in both ophthalmology and vascular imaging. The great advantage of OTIS is that it makes images in real time during surgery, unlike conventional histology that takes 24 to 48 hours after specimens are excised from the patient. Other benefits of OTIS are its automated full-specimen scanning and its ability to represent orientation of the tissue structure and—because it is non-destructive— to preserve the tissue sample for later pathological study.

The Road Ahead

Frost & Sullivan sees the consolidation of expertise and investment capital driving the enhancements needed to make optical imaging competitive with both nuclear and radiological imaging for tissue assessment. There have been a number of recent mergers and acquisitions, particularly in the OCT space. A significant example is the acquisition of St. Jude Medical by Abbott Labs in 2017 so the latter company could strengthen its portfolio of cardiovascular, diabetes and neuromodulation solutions.

St. Jude Medical designed the Dragonfly OPTIS OCT imaging catheter to improve percutaneous coronary intervention; Abbott now offers the integrated system.

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