Intra-operative Tumor Tracking Using Optical Flow and Fluorescent Imaging

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

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Initial experience with a new quantitative assessment tool for fluorescent imaging in peripheral artery disease

VASA ◽

10.1024/0301-1526/a000642 ◽

2017 ◽

Vol 46 (5) ◽

pp. 383-388 ◽

Cited By ~ 6

Author(s):

Henrik Christian Rieß ◽

Anna Duprée ◽

Christian-Alexander Behrendt ◽

Tilo Kölbel ◽

Eike Sebastian Debus ◽

...

Keyword(s):

Indocyanine Green ◽

Quantitative Assessment ◽

Tissue Perfusion ◽

Fluorescent Imaging ◽

Peripheral Artery ◽

Peripheral Bypass ◽

Before And After ◽

Artery Disease ◽

Green Fluorescent ◽

Peripheral Bypass Grafting

Abstract. Background: Perioperative evaluation in peripheral artery disease (PAD) by common vascular diagnostic tools is limited by open wounds, medial calcinosis or an altered collateral supply of the foot. Indocyanine green fluorescent imaging (ICG-FI) has recently been introduced as an alternative tool, but so far a standardized quantitative assessment of tissue perfusion in vascular surgery has not been performed for this purpose. The aim of this feasibility study was to investigate a new software for quantitative assessment of tissue perfusion in patients with PAD using indocyanine green fluorescent imaging (ICG-FI) before and after peripheral bypass grafting. Patients and methods: Indocyanine green fluorescent imaging was performed in seven patients using the SPY Elite system before and after peripheral bypass grafting for PAD (Rutherford III-VI). Visual and quantitative evaluation of tissue perfusion was assessed in an area of low perfusion (ALP) and high perfusion (AHP), each by three independent investigators. Data assessment was performed offline using a specially customized software package (Institute for Laser Technology, University Ulm, GmbH). Slope of fluorescent intensity (SFI) was measured as time-intensity curves. Values were compared to ankle-brachial index (ABI), slope of oscillation (SOO), and time to peak (TTP) obtained from photoplethysmography (PPG). Results: All measurements before and after surgery were successfully performed, showing that ABI, TTP, and SOO increased significantly compared to preoperative values, all being statistically significant (P < 0.05), except for TTP (p = 0.061). Further, SFI increased significantly in both ALP and AHP (P < 0.05) and correlated considerably with ABI, TTP, and SOO (P < 0.05). Conclusions: In addition to ABI and slope of oscillation (SOO), the ICG-FI technique allows visual assessment in combination with quantitative assessment of tissue perfusion in patients with PAD. Ratios related to different perfusion patterns and SFI seem to be useful tools to reduce factors disturbing ICG-FI measurements.

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Mental Models "Midst the Optical Flow

PsycEXTRA Dataset ◽

10.1037/e665412011-336 ◽

1992 ◽

Author(s):

Jeremy M. A. Beer

Keyword(s):

Optical Flow ◽

Mental Models

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Motion correction in PET/CT

Nuklearmedizin ◽

10.1055/s-0038-1625215 ◽

2005 ◽

Vol 44 (S 01) ◽

pp. S46-S50 ◽

Cited By ~ 5

Author(s):

M. Dawood ◽

N. Lang ◽

F. Büther ◽

M. Schäfers ◽

O. Schober ◽

...

Keyword(s):

Optical Flow ◽

Motion Correction ◽

Motion Vector ◽

Emission Tomography ◽

Cardiac Pet ◽

Novel Approach ◽

Positron Emission ◽

Pet Ct ◽

Flow Algorithm ◽

Motion Vector Field

Summary:Motion in PET/CT leads to artifacts in the reconstructed PET images due to the different acquisition times of positron emission tomography and computed tomography. The effect of motion on cardiac PET/CT images is evaluated in this study and a novel approach for motion correction based on optical flow methods is outlined. The Lukas-Kanade optical flow algorithm is used to calculate the motion vector field on both simulated phantom data as well as measured human PET data. The motion of the myocardium is corrected by non-linear registration techniques and results are compared to uncorrected images.

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