Near-infrared (NIR) optical imaging is a non-invasive and non-ionizing modality that is emerging as a diagnostic/prognostic tool for breast cancer and other applications related to functional brain mapping. In recent years, hand-held based optical imaging devices are developed for clinical translation of the technology, as opposed to the various bulky optical imagers available. Herein, we review the different hand-held based NIR devices developed to date, in terms of the measurement techniques implemented (continuous wave, time or frequency-domain), the imaging methods used, and the specific applications towards which they were applied. The advantages and disadvantages of the different hand-held optical devices are described and also compared with respect to a novel hand-held based device currently developed in our Optical Imaging Laboratory towards three-dimensional tomography studies.
"2.2 Hemodynamic Response by NIRS Optical brain imaging exploit unique property of light to image the brain for clinical as well basic science related applications. Near Infrared (IR) light (wavelength 600 -1000 nm) easily penetrates the biological tissue (S. Erickson et al, 2009, M. Tamura et al, 1997). Figure 1 shows absorption spectra of HHB and HbO 2 . "
[Show abstract][Hide abstract] ABSTRACT: To understand Working of Human Brain measurements related to the brain
function are required. These measurements should be possibly non-invasive.
Brain should be disturbed as less as possible during the measurement.
Integration of various modalities plays a vital role in understanding the
cognitive and the behavioral changes in the human brain. It is an important
source of converging evidence about specific aspects of neural functions and
dysfunctions under certain pathological conditions. Focal changes in cortical
blood flow are tightly coupled with the changes in neuronal activity. This
constitutes the option to map the hemodynamic response and infer principles of
the cortical processing, even of complex tasks. The very high temporal
resolution of EEG and good spatial resolution by NIRS make this concurrent
measurement unique to study the spatio-temporal dynamics of large scale
neuronal networks in the human brain. Such integration of two techniques will
help to overcome the limitations of a specific method. Such as insensitivity of
electroencephalogram (EEG) to unsynchronized neural events or lack of near
infrared spectroscopy (NIRS) to low metabolic demand. A combination of EEG and
NIRS will be more informative than the two separate analyses in both
International Journal of Computer Applications 07/2013; 63(5). DOI:10.5120/10464-5175
"The hand-held probe of the Gen-2 optical imager is a forked probe design capable of conforming to tissue surface areas with minimal compression (see Figure 1(A)). The forked probe design allows for both reflectance as well as transillumination imaging approach, unlike all other hand-held imaging systems that are capable of only reflectance imaging [1–22]. There are 3 sources on each of the forked probe head, configured such that there is maximum area of illumination of the imaged region by the 4 × 5 cm2 probe head . "
[Show abstract][Hide abstract] ABSTRACT: Hand-held near-infrared (NIR) optical imagers are developed by various researchers towards non-invasive clinical breast imaging. Unlike these existing imagers that can perform only reflectance imaging, a generation-2 (Gen-2) hand-held optical imager has been recently developed to perform both reflectance and transillumination imaging. The unique forked design of the hand-held probe head(s) allows for reflectance imaging (as in ultrasound) and transillumination or compressed imaging (as in X-ray mammography). Phantom studies were performed to demonstrate two-dimensional (2D) target detection via reflectance and transillumination imaging at various target depths (1-5 cm deep) and using simultaneous multiple point illumination approach. It was observed that 0.45 cc targets were detected up to 5 cm deep during transillumination, but limited to 2.5 cm deep during reflectance imaging. Additionally, implementing appropriate data post-processing techniques along with a polynomial fitting approach, to plot 2D surface contours of the detected signal, yields distinct target detectability and localization. The ability of the gen-2 imager to perform both reflectance and transillumination imaging allows its direct comparison to ultrasound and X-ray mammography results, respectively, in future clinical breast imaging studies.
"Much further work in this respect is needed. Regarding detection systems, it would be ideal to have a hand-held device  to image sacroiliac joints and spine in the rheumatology clinic. The in vivo molecular imaging could shorten the time required to diagnose AS. "
[Show abstract][Hide abstract] ABSTRACT: The diagnosis of ankylosing spondylitis is made from a combination of clinical features and the presence of radiographic evidence that may be detected only after many years of inflammatory back pain. It is not uncommon to have a diagnosis confirmed 5 to 10 years after the initial onset of symptoms. Development of a more-sensitive molecular imaging technology to detect structural changes in the joints would lead to earlier diagnosis and quantitative tracking of ankylosis progression. Progressive ankylosis (ank/ank) mice have a loss of function in the Ank gene, which codes for a regulator of PPi transport. In this study, we used these ank/ank mutant mice to assess a noninvasive, quantitative measure of joint ankylosis with near-infrared (NIR) molecular imaging in vivo.
Three age groups (8, 12, and 18 weeks) of ank/ank (15 mice) and wild-type littermates (12 +/+ mice) were assessed histologically and radiographically. Before imaging, OsteoSense 750 (bisphosphonate pamidronate) was injected i.v. Whole-body images were analyzed by using the multispectral Maestro imaging system.
OsteoSense 750 signals in the paw joints were higher in ank/ank mice in all three age groups compared with controls. In the spine, significantly higher OsteoSense 750 signals were detected early, in 8-week-old ank/ank mice compared with controls, although minimal radiographic differences were noted at this time point. The molecular imaging changes in the ank/ank spine (8 weeks) were supported by histologic changes, including calcium apatite crystals at the edge of the vertebral bodies and new syndesmophyte formation.
Changes in joint pathology of ank/ank mice, as evaluated by histologic and radiographic means, are qualitative, but only semiquantitative. In contrast, molecular imaging provides a quantitative assessment. Ankylosis in ank/ank mice developed simultaneously in distal and axial joints, contrary to the previous notion that it is a centripetal process. NIR imaging might be feasible for early disease diagnosis and for monitoring disease progression in ankylosing spondylitis.
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