title: Towards whole-body fluorescence imaging in humans.
abstract: Dynamic near-infrared fluorescence (DNIF) whole-body imaging of small animals has become a popular tool in experimental biomedical research. In humans, however, the field of view has been limited to body parts, such as rheumatoid hands, diabetic feet or sentinel lymph nodes. Here we present a new whole-body DNIF-system suitable for adult subjects. We explored whether this system (i) allows dynamic whole-body fluorescence imaging and (ii) can detect modulations in skin perfusion. The non-specific fluorescent probe indocyanine green (ICG) was injected intravenously into two subjects, and fluorescence images were obtained at 5 Hz. The in- and out-flow kinetics of ICG have been shown to correlate with tissue perfusion. To validate the system, skin perfusion was modulated by warming and cooling distinct areas on the chest and the abdomen. Movies of fluorescence images show a bolus passage first in the face, then in the chest, abdomen and finally in the periphery (~10, 15, 20 and 30 seconds, respectively). When skin perfusion is augmented by warming, bolus arrives about 5 seconds earlier than when the skin is cooled and perfusion decreased. Calculating bolus arrival times and spatial fitting of basis time courses extracted from different regions of interest allowed a mapping of local differences in subcutaneous skin perfusion. This experiment is the first to demonstrate the feasibility of whole-body dynamic fluorescence imaging in humans. Since the whole-body approach demonstrates sensitivity to circumscribed alterations in skinperfusion, it may be used to target autonomous changes in polyneuropathy and to screen for peripheral vascular diseases.
authors.affiliation: Department of Neurology, Charité University Medicine Berlin, Berlin, Germany ; Machine Learning Department, Berlin Institute of Technology, Berlin, Germany ; Center for Stroke Research, Charité University Medicine Berlin, Berlin, Germany.
authors.forename: Sophie K
authors.initials: SK
authors.lastname: Piper
authors.affiliation: Department of Neurology, Charité University Medicine Berlin, Berlin, Germany ; Machine Learning Department, Berlin Institute of Technology, Berlin, Germany ; Center for Stroke Research, Charité University Medicine Berlin, Berlin, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Habermehl
authors.affiliation: Department of Neurology, Charité University Medicine Berlin, Berlin, Germany ; NIRx Medizintechnik, Berlin, Germany.
authors.forename: Christoph H
authors.initials: CH
authors.lastname: Schmitz
authors.affiliation: Institute of Physiology, Charité University Medicine Berlin, Berlin, Germany.
authors.forename: Wolfgang M
authors.initials: WM
authors.lastname: Kuebler
authors.affiliation: Department of Neurology, Charité University Medicine Berlin, Berlin, Germany ; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany ; Clinic for Cognitive Neurology, University Hospital Leipzig, Leipzig, Germany.
authors.forename: Hellmuth
authors.initials: H
authors.lastname: Obrig
authors.affiliation: Department of Neurology, Charité University Medicine Berlin, Berlin, Germany ; Center for Stroke Research, Charité University Medicine Berlin, Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Steinbrink
authors.affiliation: Department of Neurology, Charité University Medicine Berlin, Berlin, Germany ; Machine Learning Department, Berlin Institute of Technology, Berlin, Germany ; Center for Stroke Research, Charité University Medicine Berlin, Berlin, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Mehnert
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D005453:Fluorescence; D006801:Humans; D007208:Indocyanine Green; D061848:Optical Imaging; D012867:Skin / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism*; D051598:Whole Body Imaging / Q000295:instrumentation / Q000379:methods*
chemical_list: D007208:Indocyanine Green