Velocity profiles in the rat cerebral microvessels and its change following neural activation studied by optical coherence tomography

Seki, Junji; Satomura, Yutaka; Ooi, Yasuhiro; Yanagida, Toshio; Seiyama, Akitoshi

doi:10.1016/s0021-9290(06)85558-2

Cited by 12 publications

(13 citation statements)

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“…In the brain, measurements were technically limited to the surface pial vessels of rats [28] and mice [29]. A velocity pulse was observed, while no changes in the width of vessels could be detected, correlating well with our results in the human.…”

Section: Discussionsupporting

confidence: 88%

Dependence of Brain Intravoxel Incoherent Motion Perfusion Parameters on the Cardiac Cycle

et al. 2013

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Measurement of microvascular perfusion with Intravoxel Incoherent Motion (IVIM) MRI is gaining interest. Yet, the physiological influences on the IVIM perfusion parameters (“pseudo-diffusion” coefficient D*, perfusion fraction f, and flow related parameter fD*) remain insufficiently characterized. In this article, we hypothesize that D* and fD*, which depend on blood speed, should vary during the cardiac cycle. We extended the IVIM model to include time dependence of D* = D*(t), and demonstrate in the healthy human brain that both parameters D* and fD* are significantly larger during systole than diastole, while the diffusion coefficient D and f do not vary significantly. The results non-invasively demonstrate the pulsatility of the brain’s microvasculature.

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Section: Discussionsupporting

confidence: 88%

Dependence of Brain Intravoxel Incoherent Motion Perfusion Parameters on the Cardiac Cycle

et al. 2013

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“…3. Biological (data about from basal membrane [52]; tight junction [53]; synapses [42,49]; intercapillary [54]) and physical parameters (the data about the blood flow [55,56]) at the BBB and cells surrounding the target (modified from Abbott [57]). cerebral microvessels.…”

Section: Blood-brain Barrier (Bbb)mentioning

confidence: 99%

Challenges in drug delivery to the brain: Nature is against us

Krol

2012

Journal of Controlled Release

134

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“…While the contribution from a pulsatile venous blood volume change is questionable, it is known that capillary blood flow has a pulsatile component 11,12 that may also affect the measured signals. The oxygen saturation of hemoglobin in blood changes as the blood flows through the smaller arterioles and capillary bed due to oxygen diffusion to the surrounding tissue.…”

Section: Arterial Saturation Measurements By Pulsementioning

confidence: 99%

Optical oximetry of volume-oscillating vascular compartments: contributions from oscillatory blood flow

2016

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We present a quantitative analysis of dynamic diffuse optical measurements to obtain oxygen saturation of hemoglobin in volume oscillating compartments. We used a phasor representation of oscillatory hemodynamics at the heart rate and respiration frequency to separate the oscillations of tissue concentrations of oxyhemoglobin (O) and deoxyhemoglobin (D) into components due to blood volume (subscript V V ) and blood flow (subscript F F ): O=O V +O F O=OV+OF , D=D V +D F D=DV+DF . This is achieved by setting the phase angle Arg(O F )−Arg(O) Arg(OF)−Arg(O) , which can be estimated by a hemodynamic model that we recently developed. We found this angle to be −72 deg −72 deg for the cardiac pulsation at 1 Hz, and −7 deg −7 deg for paced breathing at 0.1 Hz. Setting this angle, we can obtain the oxygen saturation of hemoglobin of the volume-oscillating vascular compartment, S V =|O V |/(|O V |+|D V |) SV=|OV|/(|OV|+|DV|) . We demonstrate this approach with cerebral near-infrared spectroscopy measurements on healthy volunteers at rest (n=4 n=4 ) and during 0.1 Hz paced breathing (n=3 n=3 ) with a 24-channel system. Rest data at the cardiac frequency were used to calculate the arterial saturation, S (a) S(a) ; over all subjects and channels, we found ⟨S V ⟩=⟨S (a) ⟩=0.96±0.02 ⟨SV⟩=⟨S(a)⟩=0.96±0.02 . In the case of paced breathing, we found ⟨S V ⟩=0.66±0.14 ⟨SV⟩=0.66±0.14 , which reflects venous-dominated hemodynamics at the respiratory frequency.

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Velocity profiles in the rat cerebral microvessels and its change following neural activation studied by optical coherence tomography

Cited by 12 publications

References 0 publications

Dependence of Brain Intravoxel Incoherent Motion Perfusion Parameters on the Cardiac Cycle

Dependence of Brain Intravoxel Incoherent Motion Perfusion Parameters on the Cardiac Cycle

Challenges in drug delivery to the brain: Nature is against us

Optical oximetry of volume-oscillating vascular compartments: contributions from oscillatory blood flow

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