title: Optimized multimodal functional magnetic resonance imaging/near-infrared spectroscopy probe for ultrahigh-resolution mapping.
abstract: Functional near-infrared spectroscopy (fNIRS) is an increasingly important noninvasive method in neuroscience due to its high temporal resolution and ability to independently measure oxy- and deoxy-hemoglobin. However, the relatively low spatial resolution of fNIRS makes it difficult to relate this signal to underlying anatomy. Simultaneous functional magnetic resonance imaging (fMRI) can complement fNIRS with superior spatial resolution and the ability to image the entire brain, providing additional information to improve fNIRS localization. However, current simultaneous fMRI/fNIRS acquisition methods are not optimal, due to the poor physical compatibility of existing MR coils and fNIRS optodes. Here, we present a technique to manufacture a true multimodal fMRI/fNIRS probe in which both modalities can be used with maximal sensitivity. To achieve this, we designed custom MR coils with integral fNIRS optodes using three-dimensional printing. This multimodal probe can be used to optimize spatial ([Formula: see text]) and temporal resolution (2.5 Hz) of fMRI, and it provides maximal MRI sensitivity, while allowing for high flexibility in the location and density of fNIRS optodes within the area of interest. Phantom and human data are shown to confirm the improvement in sensitivity in both modalities. This probe shows promise for addressing fundamental questions of the relation of fNIRS to physiology.
authors.affiliation: McLean Hospital , McLean Imaging Center, 115 Mill Street, Belmont, Massachusetts 02478, United States ; Tufts University , Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States.
authors.forename: Lia Maria
authors.initials: LM
authors.lastname: Hocke
authors.affiliation: McLean Hospital , McLean Imaging Center, 115 Mill Street, Belmont, Massachusetts 02478, United States ; Harvard Medical School , Department of Psychiatry, 25 Shattuck Street, Boston, Massachusetts 02115, United States.
authors.forename: Kenroy
authors.initials: K
authors.lastname: Cayetano
authors.affiliation: McLean Hospital , McLean Imaging Center, 115 Mill Street, Belmont, Massachusetts 02478, United States ; Harvard Medical School , Department of Psychiatry, 25 Shattuck Street, Boston, Massachusetts 02115, United States.
authors.forename: Yunjie
authors.initials: Y
authors.lastname: Tong
authors.affiliation: McLean Hospital , McLean Imaging Center, 115 Mill Street, Belmont, Massachusetts 02478, United States ; Harvard Medical School , Department of Psychiatry, 25 Shattuck Street, Boston, Massachusetts 02115, United States.
authors.forename: Blaise
authors.initials: B
authors.lastname: Frederick
keywords: functional magnetic resonance imaging; functional near-infrared spectroscopy; optics; simultaneous measurements; ultra-high spatial resolution; ultra-high temporal resolution