TY  - JOUR
A1  - Haeussinger, Florian B.
A1  - Heinzel, Sebastian
A1  - Hahn, Tim
A1  - Schecklmann, Martin
A1  - Ehlis, Ann-Christine
A1  - Fallgatter, Andreas J.
T1  - Simulation of Near-Infrared Light Absorption Considering Individual Head and Prefrontal Cortex Anatomy: Implications for Optical Neuroimaging
JF  - PLoS ONE
N2  - Functional near-infrared spectroscopy (fNIRS) is an established optical neuroimaging method for measuring functional hemodynamic responses to infer neural activation. However, the impact of individual anatomy on the sensitivity of fNIRS measuring hemodynamics within cortical gray matter is still unknown. By means of Monte Carlo simulations and structural MRI of 23 healthy subjects (mean age: (25.0 +/- 2.8) years), we characterized the individual distribution of tissue-specific NIR-light absorption underneath 24 prefrontal fNIRS channels. We, thereby, investigated the impact of scalp-cortex distance (SCD), frontal sinus volume as well as sulcal morphology on gray matter volumes (V(gray)) traversed by NIR-light, i.e. anatomy-dependent fNIRS sensitivity. The NIR-light absorption between optodes was distributed describing a rotational ellipsoid with a mean penetration depth of (23.6 +/- 0.7) mm considering the deepest 5% of light. Of the detected photon packages scalp and bone absorbed (96.4 +/- 9: 7)% and V(gray) absorbed (3.1 +/- 1.8)% of the energy. The mean V(gray) volume (1.1 +/- 0.4)cm(3) was negatively correlated (r = - .76) with the SCD and frontal sinus volume (r = - .57) and was reduced by 41.5% in subjects with relatively large compared to small frontal sinus. Head circumference was significantly positively correlated with the mean SCD (r = .46) and the traversed frontal sinus volume (r = .43). Sulcal morphology had no significant impact on V(gray). Our findings suggest to consider individual SCD and frontal sinus volume as anatomical factors impacting fNIRS sensitivity. Head circumference may represent a practical measure to partly control for these sources of error variance.
KW  - Beer-lambert law
KW  - Adult head
KW  - Human brain
KW  - Spectroscopy fnirs
KW  - Photon migration
KW  - Propagation
KW  - Scattering
KW  - Model
KW  - Tissues
KW  - Media
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-142311
VL  - 6
IS  - 10
ER  - 
TY  - JOUR
A1  - Borisjuk, Ljudmilla
A1  - Rolletschek, Hardy
A1  - Fuchs, Johannes
A1  - Melkus, Gerd
A1  - Neuberger, Thomas
T1  - Low and High Field Magnetic Resonance for \(in\) \(Vivo\) Analysis of Seeds
JF  - Materials
N2  - Low field NMR has been successfully used for the evaluation of seed composition and quality, but largely only in crop species. We show here that 1.5T NMR provides a reliable means for analysing the seed lipid fraction present in a wide range of species, where both the seed size and lipid concentration differed by >10 fold. Little use of high field NMR has been made in seed research to date, even though it potentially offers many opportunities for studying seed development, metabolism and storage. Here we demonstrate how 17.5T and 20T NMR can be applied to image seed structure, and analyse lipid and metabolite distribution. We suggest that further technical developments in NMR/MRI will facilitate significant advances in our understanding of seed biology.
KW  - Time-domain NMR
KW  - H-1-NMR spectroscopy
KW  - Soybean seeds
KW  - Human brain
KW  - Oil
KW  - Storage
KW  - Plants
KW  - Deterioration
KW  - Transport
KW  - Gradients
KW  - NMR
KW  - MRI
KW  - seed quality
KW  - Crop seed
KW  - lipid imaging
KW  - sucrose allocation
KW  - seed aging
KW  - (13)C
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140910
VL  - 4
IS  - 8
ER  -