Systems and methods for pedal revascularization assessment

Inventors

Lee, Kijoon • Dong, Jing • Bi, Renzhe

Assignees

Pedra Technology Pte Ltd

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 provides a system for assessment of peripheral blood flow characteristics in deep tissue near a patient's foot using at least one diffuse optical flow (DOF) sensor. A support structure is configured to be positioned onto the patient's foot, and the DOF sensor is carried by the support structure with the DOF sensor positioned in optical communication with the skin surface. The DOF sensor includes a return optical conduit and at least one input optical fiber with an end positioned proximate the skin surface, and the input optical fiber is in optical communication with a coherent laser light source.

The system analyzes data from the at least one DOF sensor to determine blood perfusion characteristics in arterioles and capillaries near the sensor location. The analysis includes determining the spatial speckle contrast ratio (Ks) or the temporal speckle contrast ratio (Kt), and determining 1/Ks^2 or 1/Kt^2 from intensity fluctuations, and correlating those values with blood flow. The DOF sensor is configured to capture light diffusively into tissue and transmitted at a depth of penetration between 5 mm and 50 mm.

The disclosed approach further includes real-time assessment by disposing the DOF sensor proximate a skin surface of a patient in optical communication with a first location on a foot, and disposing light delivery through input optical fiber ends positioned proximate a second location on the foot. Measurements of intensity fluctuation are obtained from a depth of penetration between 5 mm and 50 mm within a patient's microcirculatory channels, and the determined blood flow characteristics are signaled to an operator. The disclosed configurations include using multiple DOF sensors disposed at multiple locations corresponding to different topographical locations and different pedal angiosomes.

Claims Coverage

The partial content identifies three independent claims: a system claim and two method claims. Across these, the inventive features cover DOF sensing with coherent laser light, speckle contrast-based computation using spatial or temporal Ks/Kt and reciprocal-squared terms, correlation of those values with blood flow within a 5 mm to 50 mm penetration depth, and operator feedback/signaling, with multi-location/angiosome mapping and real-time or interventional-efficacy use cases represented across the method claims.

Across the independent claims, the core coverage is a DOF-based system and corresponding methods that deliver coherent laser light via optical fibers to tissue, obtain intensity fluctuation measurements from microcirculatory channels within a specified 5 mm to 50 mm penetration depth, compute spatial or temporal speckle contrast (Ks or Kt) and reciprocal-squared terms (1/Ks^2 or 1/Kt^2), correlate those values with blood flow characteristics, and signal those characteristics to an operator, including multi-location assessment across different pedal angiosomes/different angiosomes and embodiments for real-time assessment and extremity-based evaluation.

Stated Advantages

Documented Applications