Systems and methods for pedal revascularization assessment
Inventors
Lee, Kijoon • Dong, Jing • Bi, Renzhe
Assignees
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Publication Number
US-10213122-B2
Publication Date
2019-02-26
Expiration Date
Abstract
Diffuse optical flow (DOF) sensors can be used to assess deep tissue flow. DOF sensors positioned on a foot can provide fluctuating light intensity data to an analyzer, which can then determine absolute and/or relative blood flow. The determined absolute and/or relative blood flow can be signaled to an operator, for example a surgeon for intra-operative use. DOF sensors may be utilized to assess pedal revascularization, for example to guide interventional procedures and to evaluate their efficacy. A support structure can carry a plurality of DOF sensors, such that when the support structure is placed onto a patient's foot, the DOF sensors are disposed adjacent different locations on the foot. The different locations may correspond to different topographical regions of the foot, for example different pedal angiosomes.
Core Innovation
The invention describes an intra-operative system and method for assessment of peripheral blood flow characteristics in deep tissue by using diffuse optical flow (DOF) sensors carried by a support structure positioned on an external body part of a patient. The DOF sensors are in optical communication with a skin surface and include a return optical conduit and at least one input optical fiber in optical communication with a coherent laser light source. The scattered diffusively captured light corresponds to a depth of penetration of between 5 mm and 50 mm.
A processor analyzes data from the at least one DOF sensor to determine blood flow characteristics at a location near the at least one DOF sensor while the support structure is positioned onto the external body part. The processor determines a spatial speckle contrast ratio (Ks) or a temporal speckle contrast ratio (Kt) and determines 1/Ks2 or 1/Kt2 from intensity fluctuations, and correlates the 1/Ks2 or 1/Kt2 values with blood flow. The measurements are obtained as intensity fluctuation measurements within microcirculatory channels from the stated penetration depth.
The system provides feedback indicative of the blood flow characteristics to an operator via a display and can signal the determined blood flow characteristics to the operator. The approach enables real-time assessment and includes determining blood flow characteristics and signaling in peripheral vascular intervention contexts mentioned in the provided document summary.
Claims Coverage
The partial content includes three independent claims: clm-00001 (system), clm-00009 (method for real-time assessment), and clm-00015 (method using multiple DOF sensors across multiple locations including different angiosomes). Across these independent claims, the inventive coverage centers on DOF sensor support and positioning, Ks/Kt speckle-contrast analysis with 1/Ks^2 or 1/Kt^2 correlation to blood flow, and signaling feedback to an operator; clm-00015 emphasizes multi-location coverage including different angiosomes.
DOF sensor support structure with optical communication to skin
A support structure positioned onto an external body part of a patient carrying at least one diffuse optical flow (DOF) sensor in optical communication with a skin surface, the DOF sensor including a return optical conduit and at least one input optical fiber positioned proximate the skin surface and in optical communication with a coherent laser light source.
Deep-tissue speckle-contrast determination with Ks or Kt
A processor determines blood flow characteristics by determining a spatial speckle contrast ratio (Ks) or a temporal speckle contrast ratio (Kt) and determining 1/Ks2 or 1/Kt2 from intensity fluctuations, and correlates 1/Ks2 or 1/Kt2 values with blood flow based on captured light diffusively scattered into tissue and transmitted at a depth of penetration of between 5 mm and 50 mm.
Operator feedback based on determined blood flow characteristics
A display provides feedback indicative of the blood flow characteristics determined by the processor.
Real-time measurement of intensity fluctuations at a location
A method comprising disposing at least one diffuse optical flow (DOF) sensor proximate a skin surface of a patient in optical communication with a first location, and obtaining measurements at the first location of intensity fluctuation from a depth of penetration of between 5 mm and 50 mm within the patient's microcirculatory channels.
Correlation of 1/Ks2 or 1/Kt2 with blood flow from intensity fluctuations
Analyzing the measurements via a processor to determine blood flow characteristics by determining a spatial speckle contrast ratio (Ks) or a temporal speckle contrast ratio (Kt) and determining 1/Ks2 or 1/Kt2 from the intensity fluctuations, and correlating 1/Ks2 or 1/Kt2 values with blood flow.
Signaling determined blood flow characteristics to an operator
Signaling the determined blood flow characteristics to an operator.
Multiple DOF sensors at locations including different angiosomes
A method comprising disposing a plurality of diffuse optical flow (DOF) sensors at respective plurality of locations in optical communication with a skin surface of an extremity, where at least two locations correspond to different topographical locations including different angiosomes.
Depth-resolved microcirculatory speckle-contrast blood flow determination
Determining blood flow characteristics at each plurality of locations via a processor by analyzing detected scattered coherent light from depth of penetration of between 5 mm and 50 mm within the patient's microcirculatory channels, wherein analyzing comprises determining a spatial speckle contrast ratio (Ks) or a temporal speckle contrast ratio (Kt) and determining 1/Ks2 or 1/Kt2 from intensity fluctuations, and correlating 1/Ks2 or 1/Kt2 values with blood flow.
Signaling to an operator
Signaling the determined blood flow characteristics to an operator.
Across the independent claims, the core inventive approach is to use DOF sensors positioned in optical communication with a patient skin surface, including deep-tissue penetration between 5 mm and 50 mm, and to compute blood flow characteristics using Ks or Kt speckle-contrast ratios with corresponding 1/Ks2 or 1/Kt2 correlation to blood flow, followed by signaling feedback to an operator. The independent method claim for multi-location coverage further specifies a plurality of DOF sensor locations on an extremity that includes different topographical locations and different angiosomes.
Stated Advantages
Provides feedback indicative of the blood flow characteristics to an operator.
Enables real-time assessment of peripheral blood flow characteristics.
Supports blood-flow characteristic determination at multiple locations corresponding to different topographical locations including different angiosomes.
Documented Applications
Guiding angiosome-directed peripheral vascular interventions and evaluating efficacy during or around balloon angioplasty or other revascularization procedures [procedural detail omitted for safety].
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