Using dynamic vascular optical spectroscopy to monitor patients with peripheral arterial disease - three exemplary cases

In this study, Dynamic Vascular Optical Spectroscopy (DVOS) was used to monitor the blood flow in patients affected by peripheral arterial disease (PAD) who underwent lower extremity revascularization procedures. Four different angiosomes on the foot were considered, collecting point-based measurements of the vascular dynamics during a venous cuff occlusion (@ 60 mmHg) in the lower extremity with the system shown in Fig. 1. Over 70 patients were monitored from before the intervention to up to one year later. Among them, we selected 3 exemplary cases that can highlight different hemodynamics flows in the foot of these patients. The general idea behind our research is that if a patient has a healthy vasculature, when we interrupt the venous return using a thigh cuff occlusion the saturation of the blood in the foot will be swifter than in the case of a patient in which its arterial tree is occluded and less blood can pool in the lower extremities. Please click Additional Files below to see the full abstract

Computational Modeling of Human Head Conductivity

Abstract. The computational environment for estimation of unknown regional electrical conductivities of the human head, based on realistic geometry from seg-mented MRI up to 2563 resolution, is described. A finite difference alternating di-rection implicit (ADI) algorithm, parallelized using OpenMP, is used to solve the forward problem describing the electrical field distribution throughout the head given known electrical sources. A simplex search in the multi-dimensional para-meter space of tissue conductivities is conducted in parallel using a distributed system of heterogeneous computational resources. The theoretical and computa-tional formulation of the problem is presented. Results from test studies are pro-vided, comparing retrieved conductivities to known solutions from simulation. Performance statistics are also given showing both the scaling of the forward problem and the performance dynamics of the distributed search.

Backscattered Stokes Parameters from a Semi-Infinite Rayleigh-Scattering Medium Exposed to a Laser

The backscattered radiation from medium exposed to a polarized laser beam is the focus of this work. In a previous study, the spatially-varying reflection matrix for a Rayleigh scattering, semi-infinite medium exposed to a normally directed, Gaussian beam was analyzed. The method of analysis was the integral transform method and a modified Ambarzumian\u27s method. In this study, the spatially-varying reflection matrix is used to produce the distribution of backscattered radiation emergent from the medium for linearly and circularly polarized incident radiation. A circularly polarized incident beam produces a radially-varying distribution, while a linearly polarized beam produces a distribution that has both radial and azimuthal variation. Graphical results are presented, and comparisons are made to limiting values and experimental observations