Samtidig Evaluering af Cerebral Hæmodynamik og lysspredning Egenskaber for<em> In vivo</em> Rottehjerne ved brug af multispektral diffus refleksionsbilleddannelse
Summary
Den samtidige vurdering af cerebrale hæmodynamik og lysspredningsegenskaber in vivo rotte hjernevæv vist ved anvendelse af en konventionel multispektral diffus reflektans imaging system.
Abstract
The simultaneous evaluation of cerebral hemodynamics and the light scattering properties of in vivo rat brain tissue is demonstrated using a conventional multispectral diffuse reflectance imaging system. This system is constructed from a broadband white light source, a motorized filter wheel with a set of narrowband interference filters, a light guide, a collecting lens, a video zoom lens, and a monochromatic charged-coupled device (CCD) camera. An ellipsoidal cranial window is made in the skull bone of a rat under isoflurane anesthesia to capture in vivo multispectral diffuse reflectance images of the cortical surface. Regulation of the fraction of inspired oxygen using a gas mixture device enables the induction of different respiratory states such as normoxia, hyperoxia, and anoxia. A Monte Carlo simulation-based multiple regression analysis for the measured multispectral diffuse reflectance images at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm) is then performed to visualize the two-dimensional maps of hemodynamics and the light scattering properties of the in vivo rat brain.
Introduction
Multispektral diffus reflektans billeddannelse er den mest almindelige teknik til opnåelse af et rumligt kort over iboende optiske signaler (IOSs) i cortexvæv. IOSs observeret i in vivo-hjerne er hovedsageligt tilskrives tre fænomener: Variationer i lysabsorption og lysspredende egenskaber på grund af kortikale hæmodynamik, variation i absorption afhængigt af reduktion eller oxidation af cytochromer i mitochondrier, og variationer i lysspredningsegenskaber induceret af morfologiske ændringer 1.
Lys i det synlige (VIS) til nær-infrarøde (NIR) spektralområde absorberes effektivt og spredt af biologisk væv. Den diffuse reflektansspektret af in vivo hjerne er kendetegnet ved absorption og spredning spektre. De nedsatte spredningskoefficienterne u-s 'af hjernevæv i bølgelængdeområdet resultat VIS-til-NIR i en monoton spredning spektrum exhibiting mindre størrelser på længere bølgelængder. Den reducerede spredningskoefficient spektrum μ s '(λ) kan approksimeres til at være i form af styrkeloven funktion 2, 3 som μ s' (λ) = a × λ -b. Den spredende strøm b er relateret til størrelsen af biologiske spredere i levende væv 2, 3. Morfologiske ændringer i vævet og reduktion af levedygtigheden af levende cortexvæv kan påvirke størrelsen af de biologiske spredere 4, 5, 6, 7, 8, 9.
Et optisk system til multispektral diffus reflektans billeddannelse kan let konstrueres ud fra en glødelampe liGht kilde, enkle optiske komponenter og en monokromatisk ladet koblet enhed (CCD). Derfor er forskellige algoritmer og optiske systemer til multispektral diffus reflektansbilleddannelse blevet anvendt til at evaluere kortikal hæmodynamik og / eller vævsmorfologi 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 .
Fremgangsmåden beskrevet i denne artikel anvendes til at visualisere både hemodynamik og lette spredningsegenskaber af rottehjernevæv in vivo ved anvendelse af et konventionelt multispektralt diffus reflektansbilleddannelsessystem. Fordelene ved denne metode over alternative teknikker er evnen til at evaluere spatiotemporale ændringer i både cerebral hæmodynamik og kortikal vævmorfologi, samt dets anvendelighed til forskellige hjerne dysfunktion dyremodeller. Derfor vil metoden være passende for undersøgelser af traumatisk hjerneskade, epileptisk anfald, slagtilfælde, og iskæmi.
Protocol
Representative Results
Discussion
Det mest kritiske trin i denne protokol er fjernelsen af den tyndere kraniet området til at gøre den kraniale vindue; dette skal udføres omhyggeligt for at undgå uventet blødning. Dette trin er vigtigt for at opnå høj kvalitet Multispektral diffus reflektans billeder med stor nøjagtighed. Det anbefales at bruge af et stereomikroskop for den kirurgiske procedure, hvis det er muligt. Små stykker af gelatine svamp er egnede til hæmostase.
Det optiske system beskrevet i denne art…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Part of this work was supported by a Grant-in-Aid for Scientific Research (C) from the Japanese Society for the Promotion of Science (25350520, 22500401, 15K06105) and the US-ARMY ITC-PAC Research and Development Project (FA5209-15-P-0175).
Materials
| 150-W halogen-lamp light source | Hayashi Watch Works Co., Ltd, Tokyo, Japan | LA-150SAE | |
| Light guide | Hayashi Watch Works Co., Ltd, Tokyo, Japan | LGC1-5L1000 | |
| Collecting lens | Hayashi Watch Works Co., Ltd, Tokyo, Japan | SH-F16 | |
| Interference filters l@500nm | Edmund Optics Japan Ltd, Tokyo, Japan | #65088 | |
| Interference filters l@520nm | Edmund Optics Japan Ltd, Tokyo, Japan | #65093 | |
| Interference filters l@540nm | Edmund Optics Japan Ltd, Tokyo, Japan | #65096 | |
| Interference filters l@560nm | Edmund Optics Japan Ltd, Tokyo, Japan | #67766 | |
| Interference filters l@570nm | Edmund Optics Japan Ltd, Tokyo, Japan | #67767 | |
| Interference filters l@580nm | Edmund Optics Japan Ltd, Tokyo, Japan | #65646 | |
| Interference filters l@600nm | Edmund Optics Japan Ltd, Tokyo, Japan | #65102 | |
| Interference filters l@730nm | Edmund Optics Japan Ltd, Tokyo, Japan | #65115 | |
| Interference filters l@760nm | Edmund Optics Japan Ltd, Tokyo, Japan | #67777 | |
| Motorized filter wheel | Andover Corporation, NH, USA | FW-MOT-12.5 | |
| 16-bit cooled CCD camera | Bitran, Japan | BS-40 | |
| Video zoom lens | Edmund Optics Japan Ltd, Tokyo, Japan | VZMTM300i | |
| Spectralon white standard with 99% diffuse reflectance | Labsphere Incorporated, North Sutton, NH, USA | SRS-99-020 |
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