{
  "abstract": "Diffuse optical measurements of blood flow, blood volume, and blood oxygenation often use separate devices and photon populations. Combining these contrasts within a common photon population would enable their direct co-registration while retaining time-of-flight-based depth discrimination. We introduce dual-wavelength time-of-flight interferometric speckle-contrast optical spectroscopy (TOF-iSCOS), built on an interferometric near-infrared spectroscopy (iNIRS) architecture that temporally multiplexes 780 and 852 nm swept lasers through a shared detection channel. It recovers co-registered flow-sensitive field dynamics and wavelength-resolved attenuation from the same complex-field acquisition. Three 50 ps TOF gates sample increasingly late-arriving photons. Within each gate, g1 was calculated directly as the normalized temporal autocorrelation of the reconstructed complex field.{kappa} 2(T) was reconstructed by finite-time integration of measured g1 and finite-integration fits yielded decorrelation rates. No camera speckle-variance contrast or Siegert substitution was used. Gate-integrated TPSF intensities yielded optical-density changes{Delta} OD, and division by the baseline-TPSF-weighted mean photon path length gave effective{Delta} {micro}a for two-wavelength hemoglobin inversion. In 12 forearm cuff-occlusion recordings from 11 adults, TOF-iSCOS detected flow suppression during occlusion and reactive hyperemia after release at both wavelengths. At 780 nm, the Late-minus-Early reactive-hyperemia amplitude in the relative blood-flow index (rBFI) was +0.647 (95% CI 0.194 to 1.124), whereas the Early-minus-Late cuff{Delta} {micro}a contrast was +0.196 cm-1 (95% CI 0.123 to 0.280). In the photon-limited 852 nm Late gate, the accepted-frame fraction was 0.994 for{kappa} 2-based fitting versus 0.831 for g1-based fitting. Exploratory phase-resolved analysis suggested that the initial hemoglobin response was concentrated in early-arriving photons, while later responses differed in magnitude and direction. Wavelength, field dynamics, and photon time-of-flight thus provide complementary physiological information; the largest response need not identify the phase of interest.",
  "abstract_shown": true,
  "affiliations": [
    "Institute of Physical Chemistry PAS"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "name": "K. Nowacka-Pieszak"
    },
    {
      "name": "M. Marzejon"
    },
    {
      "name": "N. Mogharari"
    },
    {
      "affs": [
        0
      ],
      "name": "D. Borycki"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4kb89nttary11.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.02.26362024",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.09.02.26362024v1.full",
  "id": "4kb89nttary11",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.09.02.26362024v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "neurology"
    ],
    [
      "openalex",
      "2741|Optical Imaging and Spectroscopy Techniques"
    ]
  ],
  "openalex": "W7211975849",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.09.02.26362024v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4kb89nttary11.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:57Z",
      "native_id": "10.64898/2026.09.02.26362024",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.09.02.26362024v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:neurology",
      "subfield": "neurology"
    }
  ],
  "title": "Dual-wavelength time-of-flight interferometric speckle-contrast optical spectroscopy (dual-wavelength TOF-iSCOS) for co-registered blood-flow and hemoglobin sensing",
  "title_text": "Dual-wavelength time-of-flight interferometric speckle-contrast optical spectroscopy (dual-wavelength TOF-iSCOS) for co-registered blood-flow and hemoglobin sensing",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:57Z",
  "url": "https://research.draconitic.com/paper/4kb89nttary11",
  "venue": "medRxiv",
  "versions": []
}