{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T20:25:53Z","timestamp":1792787153423,"version":"4.5.0"},"reference-count":0,"publisher":"SPIE-Intl Soc Optical Eng","issue":"02","license":[{"start":{"date-parts":[[2026,4,16]],"date-time":"2026-04-16T00:00:00Z","timestamp":1776297600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"MIT Lincoln Laboratory Lincoln Scholars Program","id":[{"id":"https:\/\/ror.org\/022z6jk58","id-type":"ROR","asserted-by":"crossref"}]},{"name":"National Institutes of Health","award":["R01NS135081"],"award-info":[{"award-number":["R01NS135081"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Neurophoton."],"published-print":{"date-parts":[[2026,4,16]]},"abstract":"<jats:p>SignificanceWithin diffuse optics, speckle contrast optical spectroscopy (SCOS) has emerged as a promising alternative to the state-of-the-art technique of diffuse correlation spectroscopy (DCS) for continuous, noninvasive bedside monitoring of cerebral blood flow (CBF). Although the two methods theoretically yield equivalent relative indices of CBF (rCBFi), in practice, SCOS-based measurements require experimental calibration to obtain unbiased rCBFi values. To date, there are limited validation studies comparing SCOS and DCS in human subjects, particularly at long source\u2013detector separations (SDS) relevant to adult brain monitoring.AimWe aim to compare rCBFi from SCOS and DCS during concurrent, colocalized measurements on tissue-mimicking phantoms and humans at a large SDS of 3\u00a0cm.ApproachWe conducted concurrent SCOS and DCS measurements on temperature-ramped, two-layer, and flow phantoms, respectively. We also conducted concurrent CBF measurements on 10 healthy volunteers undergoing various physiological challenges (breath-holding, hyperventilation, pressure modulation, and squatting) designed to elicit measurable changes in blood flow. SCOS and DCS operated from a shared pulsed laser source, which enabled pulsation-resolved human CBF measurements at 3\u00a0cm SDS (DCS necessitated the use of cardiac-gated averaging).ResultsWe observed strong agreement (r=0.93, slope = 0.98) between SCOS- and DCS-derived rCBFi at 3\u00a0cm SDS and an order-of-magnitude improvement in SCOS noise performance relative to DCS during the in vivo measurements. Phantom experiments showed a small depth-sensitivity disadvantage for SCOS at the same SDS; however, this was far outweighed by its superior noise performance, yielding an order-of-magnitude improvement in SCOS contrast-to-noise ratio.ConclusionsThe results demonstrate the equivalence of properly calibrated SCOS and DCS rCBFi measurements at long SDS in adults, establishing SCOS as a viable alternative to DCS for monitoring CBF. Further validation across larger cohorts and clinical populations is warranted.<\/jats:p>","DOI":"10.1117\/1.nph.13.2.025008","type":"journal-article","created":{"date-parts":[[2026,4,16]],"date-time":"2026-04-16T14:18:25Z","timestamp":1776349105000},"page":"1-21","source":"Crossref","is-referenced-by-count":2,"title":["Comparative validation of speckle contrast optical spectroscopy against diffuse correlation spectroscopy for monitoring human cerebral blood flow"],"prefix":"10.1117","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3220-7471","authenticated-orcid":false,"given":"Tom Y.","family":"Cheng","sequence":"first","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5810-0459","authenticated-orcid":false,"given":"Mitchell B.","family":"Robinson","sequence":"additional","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Renna","sequence":"additional","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7794-8022","authenticated-orcid":false,"given":"Kuan-Cheng","family":"Wu","sequence":"additional","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zachary","family":"Starkweather","sequence":"additional","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olivia S.","family":"Kierul","sequence":"additional","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Byungchan (Kenny)","family":"Kim","sequence":"additional","affiliation":[{"name":"Boston University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander C.","family":"Howard","sequence":"additional","affiliation":[{"name":"Boston University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4995-293X","authenticated-orcid":false,"given":"David A.","family":"Boas","sequence":"additional","affiliation":[{"name":"Boston University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4617-3233","authenticated-orcid":false,"given":"Stefan A.","family":"Carp","sequence":"additional","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3568-0603","authenticated-orcid":false,"given":"Xiaojun","family":"Cheng","sequence":"additional","affiliation":[{"name":"Boston University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6758-423X","authenticated-orcid":false,"given":"Maria Angela","family":"Franceschini","sequence":"additional","affiliation":[{"name":"Massachusetts General Hospital"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"189","container-title":["Neurophotonics"],"original-title":[],"link":[{"URL":"https:\/\/www.spiedigitallibrary.org\/journals\/neurophotonics\/volume-13\/issue-02\/025008\/Comparative-validation-of-speckle-contrast-optical-spectroscopy-against-diffuse-correlation\/10.1117\/1.NPh.13.2.025008.full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T20:11:54Z","timestamp":1790194314000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.spiedigitallibrary.org\/journals\/neurophotonics\/volume-13\/issue-02\/025008\/Comparative-validation-of-speckle-contrast-optical-spectroscopy-against-diffuse-correlation\/10.1117\/1.NPh.13.2.025008.full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,16]]},"references-count":0,"journal-issue":{"issue":"02","published-online":{"date-parts":[[2026,4,1]]}},"URL":"https:\/\/doi.org\/10.1117\/1.nph.13.2.025008","relation":{},"ISSN":["2329-423X","2329-4248"],"issn-type":[{"value":"2329-423X","type":"print"},{"value":"2329-4248","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,16]]}}}