Instant, Calibration-Free Blood-Flow Measurement With A Single Optical Snapshot

A single-frame, multi-exposure time optical method enabling accurate extraction of absolute speckle decorrelation time and optimized for recovery of absolute deep-tissue blood flow.
Problem:
Accurately recovering absolute speckle decorrelation time without the use of calibration or complex instrumentation is challenging. For the use case of monitoring deep tissue blood flow this issue is compounded by faster decorrelation times, strong scattering contributions, and a heterogeneous flow environment. Though optical methods exist with the capability to extract absolute blood flow indices in this scenario they are often plagued by limited signal-to-noise ratio (SNR) and complex instrumentation. Speckle Contrast Optical Spectroscopy (SCOS) is a promising alternative that makes use of low-cost cameras to offer high SNR measurements, but typically only recovers changes in blood flow from a known baseline and makes data quality assessment difficult.
Solution:
This invention introduces a fast, single-shot SCOS approach that extracts absolute blood-flow index without calibration. By encoding many effective exposure times within one camera frame, the method recovers absolute flow dynamics while preserving high signal quality and enabling simple data quality metrics. This enables reliable, patient and baseline-independent perfusion measurements suitable for real clinical use.
Technology:
This invention adapted features from specialized rolling shutter cameras that enable capturing thousands of exposure times on a single frame. With a global reset option, the camera can be used to obtain a pixel row dependent on exposure time. As a result, the essential speckle contrast coherence parameter, that once required multiple frames or calibration, can be extracted from a single frame. With this parameter recovered, the absolute blood-flow index can be computed directly from the speckle-contrast value of every single-frame measurement with a high signal-to-noise ratio.
Advantages:

• Enable recovery of absolute speckle decorrelation time
• Delivers true, absolute blood-flow values without needing baseline normalization or external calibration
• Captures rich motion information in a single frame, enabling high speed, low latency, and reduced sensitivity to motion artifacts
• Maintains SCOS’s inherently high signal-to-noise ratio, allowing reliable measurements at low illumination and safe clinical power levels
• Uses standard hardware, making quantitative deep-tissue perfusion measurement more practical and broadly deployable 

Stage of Development:

• Proof of Concept 

SCOS with the global reset method has (A) a range of exposure time for rows of each single frame, resulting in (B) the ability to recover speckle contrast as a function of many exposure times. This method recovers (C) absolute flow index (αD_B) with high correlation to established, more complex, methods while (D) still enabling high SNR as exhibited by this arm cuff occlusion with strong blood flow pulsatility. Initial 50 seconds provide baseline blood flow, 50-100sec is response to induced ischemia in forearm, and 100-160sec is response to hyperemia.
Intellectual Property:

• In Preparation 

Reference Media: 

• Majeski, J. B. et al., SPIE., Clinical and Translational Neurophotonics; 2025 March 19: PC1330209 

Desired Partnerships:

• License
• Co-development 

Docket #25-10872