FluxData’s FD-1665 Used to Assess Rheumatoid Flare


Rheumatoid arthritis (RA) is a chronic, debilitating disease affecting over 1 million people in the United States. RA is characterized by the draining of lymphatic vessels coupled with dynamic changes in lymph node volume and flow. Impaired lymph egress from inflamed synovium is associated with joint flare in murine models of inflammatory-erosive arthritis. Unfortunately, advancements in understanding lymphatic changes have been slow, due to the lack of technology to measure and quantify lymphatic function in vivo. Lymphoscintigraphy is the current standard used in assessing lymphedema and sentinel lymph nodes in cancer patients, but is not adequate to study lymphatics in RA.
 
High-resolution MRI, power Doppler ultrasound, and near-infrared imaging that permits real-time quantification of lymphatic function have been the largest advancements thus far, and have produced a new paradigm of altered lymphatic function that underlies both accute arthritic flare and chronic inflammation. In accute flare, lymphatic drainage increases several fold, whereas no lymphatic contractions are detected in lymph vessels draining chronic arthritic joints.
 
In a study done by Homaira Rahimi, Richard Bell, Echoe M. Bouta, Ronald W. Wood, Lianping Xing, Christopher T. Ritchlin and Edward M. Schwarz, they explained the knowledge to date on lymphatics in RA, new in-vivo imaging modalities that have elucidated how lymphatics modulate acute versus chronic joint inflammation, and how these preclinical outcome measures are being translated to study RA inflammation and how effective RA therapies alter lymphatic flow and lymph nodes draining flaring joints. The discoveries were facilitated by novel imaging methods, one being the use of a custom NIR imaging system; FluxData’s FD-1665.
 
 
 
 
For the purpose of this study, FluxData’s FD-1665 was used to quantify lymphatic flow in the upper extremity. The custom NIR imaging system was used to assess lymphatic contraction frequency in a healthy human subject after ICG injection in the second, third, and fourth web spaces of both hands. The NIR excitation was monitored with a Thorlabs PM16-121 power meter adjacent to the first web space. After the injections, the upper extremities were imaged for 10 minutes to observe lymphatic flow. Visible and NIR images were collected simultaneously. Dysfunctional contractions, or no contractions, could indicate that the arthritic episode is the result of a drainage issue rather than synovial disturbances. The treatment would then be tailored accordingly.
 
The rationale for using NIR-ICG to evaluate lymphatic contractions is justified because it provides real-time information for the clinician. Using this sytem to test such has been approved by the FDA, therefore there is no major health limitations of the given technique.
 
 
 
 
 
The importance of this study is three-fold. The role of lympthatics in RA can now be examined with the advent of in-vivo imaging modalities that quantify lymphatic flow and contraction frequency. Such technical advances can empower investigators to promote understanding in three areas: redefinition of patterns of lymphatic flow anatomically, discovery of the cellular, molecular, and structural mechanisms that regulate lymphatic function and that are closely integrated with local biomechanics, inflammation, and parasympathetic innervation. Lastly, the goal is to identify novel molecular targets that will give rise to new interventions for RA flare. The advancement of noninvasive technologies was a critical first step.
 
To read the full article from the National Center for Biotechnology Information, click here.

 

Passive Optical Sensing of the Near-Surface Wind-Driven Current Profile

Understanding the near-surface current is essential to estimating upper-ocean material transport. Wind forcing and wave motions are dominant in the near-surface layer, where the highly sheared flows can differ greatly from those at depth. A study, conducted by Nathan J.M. Laxague, Brian K. Haus, David G. Ortiz-Suslow, Conor J. Smith, Guillaume Novelli, Hanjing Dai, Tamay Özgökmen, and Hans C. Graber, displays a new method for remotely measuring the directional wind and wave drift current profile near the surface. Their work follows the spectral analysis of high spatial (~0.002 m) and temporal resolution (60 Hz) wave slope images, allowing for the evaluation of near-surface current characteristics without having to rely on instruments that may disturb the flow. FluxData’s FD-1665 Polarimetric imaging system was used as part of the research.
 
The shape of near-surface current profile has been the subject of scientific inquiry for many years due to the direct impact it has on things such as: radar remote sensing, oceanic material transport, etc. The classic approach to estimating such has been to parameterize the current as aligned with the wind velocity, with the magnitude given as a strict percentage of the 10-m neutral wind speed or friction velocity.
 
Advances in computer vision technology in recent years have allowed for the evaluation of the spatiotemporal characteristics that define the short high-frequency waves that are especially affected by near-surface current.
 
Observations were performed in both the Air-Sea Interaction Saltwater Tank (ASIST) at the University of Miami’s Surge-Structure-Atmosphere Interaction (SUSTAIN) facility and the mouth of the Columbia River (MCR) along the Oregon-Washington border. For the laboratory observations, near-surface dye tracking was employed to provide a standard for Lagrangian fluid transport speed. For the field observations, FluxData’s FD-1665 polarimetric camera was mounted off the starboard bow and oriented such that it imaged an area forward and away from the ship’s wake zone.
 
 
 
     The polarimetric camera was positioned 2.47m above the mean water level
    and oriented 45° below the horizontal, with the footprint centered at 5-m fetch.
 
 

The method provided short-scale temporal and spatial information from waves without disturbing the near-interface flows that define them. The polarimeter used was FluxData’s FD-1665, a system enclosing a beamsplitter and three Basler Scout series charge-coupled devices (CCDs), each of which acquires images composed of visible light in one of the following three linear polarization states: 0°, 45°, and 90°.
 
Real-time footage captured with FluxData's polarimetric imaging system:
 
Sea surface reconstruction of a still image (all dimensions in meters)
 
 
 
 
 
Time series of a water surface reconstruction from data
 
 
 
Near-surface currents are critical in the estimation of oceanic material transports-- especially of ecologically damaging materials of spilled oil or marine debris. Based on this research alone, future parameterizations of marine transport would benefit greatly from considering the magnitude and direction of ocean-atmosphere momentum flux. Currently, this method is being applied and includes a variety of shipboard, airborne, and drifting instruments for a more thorough investigation of the small-scale dynamics.
 
Ultimately, this new technique offers previously unavailable information for the fields of physical remote sensing and near-interface fluid mechanics.
 
For a continuation of methods/conclusions, read the full AMS publication here.