Real-time Quantitative Optical Perfusion Imaging in Surgery

Study Overview
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Brief Summary
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Surgeons are nowadays unable to visualize and quantitatively evaluate microvascularisation in real-time during surgery. Complications due to vascular compromise are a major problem, especially in reconstructive surgery. Poor blood perfusion leads to ischemia and even tissue necrosis. If, however, perfusion and ischemia could be monitored during surgery, then surgeons could change their reconstructive design and the anaesthesiologists could improve perfusion with fluids, inotropes or vasopressors, if necessary. Surgeons therefore need a tool that is able to image in high resolution (microvascularisation), direct, intra-operative, in 3D (to image thrombosis, luminal narrowing or distinct overlaying vessels) and that produces quantitative data to objectify image interpretation. Optical techniques, based on the interaction of light with tissue, are able to image tissue at high resolution and in real-time. These techniques are FDA-approved and have emerged as powerful diagnostic tools in different departments of medicine, such as ophthalmology for visualizing retina vascularisation and dermatology for skin diagnostics. In this study, investigators hypothesize that four novel optical technologies: Fluorescence Imaging, Laser Speckle Contrast Imaging, Optical Coherence Tomography and Sidestream Darkfield Microscopy are able to quantitatively image perfusion in real-time during surgery.

Detailed Description
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Primary objective - Perfusion will be measured with all the techniques focussed on 4 areas; from 'good' to 'decreased' perfusion (biologically) Fluorescence Imaging (FI): Time to intensity measurements at four sides Laser Speckle Contrast Imaging (LSCI): Perfusion Units Optical Coherence Tomography (OCT): Vessel density & decorrelation time Sidestream Darkfield Microscopy (SDF): Total vessel density, proportion of perfused vessels, perfused vessel density, max flow index, De Backer score, perfusion in mm/sec. Differences in parameters between the four sites will be statistically be compared. Secondary objectives - Relation of parameters to patient outcome in terms of adverse events.

Official Title
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Real-time Quantitative Optical Perfusion Imaging in Surgery: a Prospective, Observational, In-vivo, Human, Single-center Study

Conditions
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Complications of Perfusion

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years - Scheduled for reconstructive surgery with free flap reconstruction or laparoscopic transhiatal and 3-stage transthoracic gastric tube surgery. Exclusion Criteria: Allergic to iodide (indocyanine green) Hyper-thyroidism Breastfeeding No informed consent Allergic to ephedrine Ischaemic heart disease Thyrotoxicosis Autonomic thyroid adenomas Intraoperative hypertension or tachycardia

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with OCT. | - Perfusion will be imaged with OCT and measured in total vessel density. | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with SDF. | Perfusion will be imaged with SDF and measured in microvascular flow index. | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with LSCI. | flux in perfusion units (LSCI) | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with FI. | intensity/time (FI) | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distance of watershed to fundus (GT) or artery to tip (flap) | In the FI images the distance between the end of the right gastroepiploic artery and the fundus, and the distance between the artery entry and tip of the flap can be calculated. | 1 year | 
| Measurement-time during surgery | time in minutes will be calculated during measurements | 30 minutes | 
| Number of participants with treatment-related adverse events as assessed by CTCAE v4.0 |  | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with OCT. | - Perfusion will be imaged with OCT and measured in decorrelation time. | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with SDF. | Perfusion will be imaged with SDF and measured in total vessel density. | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with SDF. | Perfusion will be imaged with SDF and measured in perfused vessel density. | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with SDF. | Perfusion will be imaged with SDF and measured in proportion of perfused vessels. | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with SDF. | Perfusion will be imaged with SDF and measured in De Backer Score. | 1 year | 
| Difference in perfusion between the antrum and fundus (GT) or the artery origin and tip (free flap) measured with SDF. | Perfusion will be imaged with SDF and measured in velocity in mm/sec. | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Optical Coherence Tomography, Fluorescence Imaging, Sidestream Darkfield Microscopy, Laser Speckle Contrast Imaging