Method for non-invasive monitoring of fluorescent tracer agent with diffuse reflecting medium with time-varying optical properties
Inventors
Shultz, Kimberly • Keating, Jennifer • Solomon, Edward • Bechtel, Kate
Assignees
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Publication Number
US-11950907-B2
Publication Date
2024-04-09
Expiration Date
Abstract
A method of assessment of renal function by monitoring a time-varying fluorescence signal emitted from a fluorescent agent from within a diffuse reflecting medium with time-varying optical properties is provided that includes using a renal monitoring system comprising at least one light source, at least one light detector, at least one optical filter, and at least one controller to provide a measurement data set comprising a plurality of measurement entries, each measurement data entry comprising at least two measurements obtained at one data acquisition time from a patient before and after administration of the fluorescent agent.
Core Innovation
The invention relates to a method of assessment of renal function by monitoring a time-varying fluorescence signal emitted from a fluorescent agent from within a diffuse reflecting medium with time-varying optical properties. A renal monitoring system provides a measurement data set using at least one light source, at least one light detector, at least one optical filter, and at least one controller, and each measurement data entry includes at least two measurements obtained at one data acquisition time from a patient before and after administration of the fluorescent agent.
The method selects measurements comprising an Flr signal detected at a third region adjacent to the diffuse reflecting medium by a filtered light detector during excitation illumination, and a DRem,filtered signal detected at the third region by the filtered light detector during emission-wavelength illumination. The processing unit includes a post-agent administration selection subunit configured to identify a post-agent administration portion and a post-equilibration portion of the measurement data set, and the post-agent administration portion is used to transform each Flr signal into an IF signal representing a detected fluorescence intensity emitted solely by the fluorescent agent from within the diffuse reflecting medium.
The transforming uses a transformation relation comprising a mathematical equation converting Flr to IF by combining the at least two measurements. The method then transforms the IF signals corresponding to the post-equilibration portion into a rate of change of the IF signals, and determines renal function based on the rate of change. In dependent implementations, the rate-related quantity is expressed as a renal decay time constant (RDTC), including single-exponential curve-fit and log-transform linear regression variants, and is further related to glomerular filtration rate (GFR).
Claims Coverage
Only one independent claim is provided (clm-00001). The claim contains five inventive features centered on region-based filtered and unfiltered fluorescence/diffuse-reflectance measurements, selecting post-agent administration and post-equilibration portions, transforming Flr into an intrinsic fluorescence (IF) signal emitted solely by the fluorescent agent, and determining renal function from the rate of change of IF, often via RDTC.
Renal function assessment using time-varying fluorescence in a diffuse reflecting medium with time-varying optical properties
Monitoring a time-varying fluorescence signal emitted from a fluorescent agent from within a diffuse reflecting medium with time-varying optical properties, using a renal monitoring system comprising at least one light source, at least one light detector, at least one optical filter, and at least one controller to provide a measurement data set from patient measurements before and after administration.
Region-based selection of fluorescence-related measurements for IF transformation
Detecting, from within the measurement data set, an Flr signal using a filtered light detector during illumination with excitatory-wavelength light, and a DRem,filtered signal using the filtered light detector during illumination with emission-wavelength light.
Post-agent administration and post-equilibration portion selection
Using a processing unit that comprises a post-agent administration selection subunit configured to identify a post-agent administration portion and a post-equilibration portion of the measurement data set.
Flr-to-IF transformation representing fluorescence emitted solely by the fluorescent agent
Transforming each Flr signal within the post-agent administration portion into an IF signal representing a detected fluorescence intensity emitted solely by the fluorescent agent from within the diffuse reflecting medium, where the transforming comprises combining the at least two measurements according to a transformation relation comprising a mathematical equation converting Flr to IF.
Rate-of-change determination of IF for renal function determination
Transforming the IF signals corresponding to the post-equilibration portion into a rate of change of the IF signals, and determining renal function based on the rate of change of the IF signals.
Claim clm-00001 broadly covers renal function assessment using time-varying fluorescence measured in a diffuse reflecting medium, with filtered fluorescence/diffuse-reflectance measurements used to transform Flr into an IF signal emitted solely by the fluorescent agent. The method selects post-agent administration and post-equilibration portions and determines renal function from the rate of change of IF, with dependent claims narrowing the rate computation via RDTC and relating RDTC to GFR.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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