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1.
Phys Med ; 32(1): 218-25, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26654116

ABSTRACT

In laparotomy surgery guided by near-infrared fluorescence imaging, the access to the field of operation is limited by the illumination and/or the imaging field. The side of cavities or organs such as the liver or the heart cannot be examined with the systems available on the market, which are too large and too heavy. In this article, we describe and evaluate a palm sized probe, whose properties, weight, size and sensitivity are adapted for guiding laparotomy surgery. Different experiments have been performed to determine its main characteristics, both on the illumination and imaging sides. The device has been tested for fluorescent molecular probe imaging in preclinical procedures, to prove its ability to be used in cancer nodule detection during surgery. This system is now CE certified for clinical procedures and Indocyanine Green imaging has been performed during clinical investigations: lymphedema and surgical resection of liver metastases of colorectal cancers.


Subject(s)
Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/surgery , Laparotomy/instrumentation , Lymphedema/diagnosis , Lymphedema/surgery , Surgery, Computer-Assisted/instrumentation , Animals , Colorectal Neoplasms/pathology , Diagnostic Imaging/instrumentation , Diagnostic Imaging/methods , Equipment Design , Female , Fluorescence , Fluorescent Dyes/chemistry , Head and Neck Neoplasms/diagnosis , Head and Neck Neoplasms/pathology , Head and Neck Neoplasms/surgery , Hepatectomy , Humans , Indocyanine Green/chemistry , Laparotomy/methods , Limit of Detection , Liver Neoplasms/diagnosis , Liver Neoplasms/pathology , Liver Neoplasms/surgery , Lymphedema/pathology , Mice , Mice, Nude , Miniaturization , Neoplasm Transplantation , Optical Fibers , Polymers/chemistry , Reproducibility of Results , Spectroscopy, Near-Infrared/methods
2.
Biomed Opt Express ; 3(9): 2306-16, 2012 Sep 01.
Article in English | MEDLINE | ID: mdl-23024922

ABSTRACT

Patent Blue V (PBV), a dye used clinically for sentinel lymph node detection, was mixed with human serum albumin (HSA). After binding to HSA, the fluorescence quantum yield increased from 5 × 10(-4) to 1.7 × 10(-2), which was enough to allow fluorescence detection and imaging of its distribution. A detection threshold, evaluated in scattering test objects, lower than 2.5 nmol × L(-1) was obtained, using a single-probe setup with a 5-mW incident light power. The detection sensitivity using a fluorescence imaging device was in the µmol × L(-1) range, with a noncooled CCD camera. Preclinical evaluation was performed on a rat model and permitted to observe inflamed nodes on all animals.

3.
Opt Express ; 19(13): 12843-54, 2011 Jun 20.
Article in English | MEDLINE | ID: mdl-21716527

ABSTRACT

We present a new method allowing the reconstruction of 3D time-domain diffuse optical tomography images, based on the time-dependent diffusion equation and an iterative algorithm (ART) using specific points on the temporal profiles. The first advantage of our method versus the full time-resolved scheme consists in considerably reducing the inverse problem resolution time. Secondly, in the presence of scattering heterogeneities, our method provides images of better quality comparatively to classical methods using full-time data or the first moments of the profiles.


Subject(s)
Algorithms , Models, Theoretical , Photons , Tomography, Optical/methods , Absorption , Animals , Computer Simulation , Humans , Neoplasms/diagnosis , Phantoms, Imaging , Scattering, Radiation , Time Factors
4.
Appl Opt ; 49(16): 3163-72, 2010 Jun 01.
Article in English | MEDLINE | ID: mdl-20517387

ABSTRACT

There has been recently a considerable interest in simultaneously reconstructing yield and lifetime distributions of fluorescent imaging agents inside a bulky tissue, since combined monitoring of these two parameters provides a potential means of in vivo interrogating quantitative and environmental information of specific molecules, as well as accessing interactions among them. It is widely accepted that an advantageous way of accomplishing the task in the context of small-animal imaging is to use a time-domain (TD) modality. In this paper, we present a full three-dimensional, featured-data algorithm for TD diffuse fluorescence tomography, which inverts the Laplace-transformed TD coupled photon diffusion equations and employs a pair of real-domain transform-factors to effectively separate the fluorescent yield and lifetime parameters. By use of a specifically designed 16x16 channel time-correlated single photon counting system and a normalized Born formulation for the inversion, the proposed scheme in a transmission mode is experimentally validated to achieve simultaneous reconstruction of the fluorescent yield and lifetime distributions with reasonable accuracy.


Subject(s)
Algorithms , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Microscopy, Fluorescence/methods , Microscopy, Fluorescence/veterinary , Tomography, Optical/methods , Tomography, Optical/veterinary , Animals , Phantoms, Imaging , Reproducibility of Results , Sensitivity and Specificity
5.
Biomed Opt Express ; 1(3): 902-910, 2010 Sep 14.
Article in English | MEDLINE | ID: mdl-21258517

ABSTRACT

We present a new near infrared optical probe for the sentinel lymph node detection, based on the recording of scattered photons. A two wavelengths setup was developed to improve the detection threshold of an injected dye: the Patent Blue V dye. The method used consists in modulating each laser diode at a given frequency. A Fast Fourier Transform of the recorded signal separates both components. The signal amplitudes are used to compute relative Patent Blue V concentration. Results on the probe using phantoms model and small animal experimentation exhibit a sensitivity threshold of 3.2 µmol/L, which is thirty fold better than the eye visible threshold.

6.
J Neurosci ; 28(52): 14189-201, 2008 Dec 24.
Article in English | MEDLINE | ID: mdl-19109501

ABSTRACT

The failure of the remyelination processes in multiple sclerosis contributes to the formation of chronic demyelinated plaques that lead to severe neurological deficits. Long-term cuprizone treatment of C57BL/6 mice resulted in pronounced white matter pathology characterized by oligodendrocyte depletion, irreversible demyelination and persistent functional deficits after cuprizone withdrawal. The use of a combination of in vivo diffusion tensor magnetic resonance imaging (DT-MRI) and histological analyses allowed for an accurate longitudinal assessment of demyelination. Injection of triiodothyronine (T(3)) hormone over a 3 week interval after cuprizone withdrawal progressively restored the normal DT-MRI phenotype accompanied by an improvement of clinical signs and remyelination. The effects of T(3) were not restricted to the later stages of remyelination but increased the expression of sonic hedgehog and the numbers of Olig2(+) and PSA-NCAM(+) precursors and proliferative cells. Our findings establish a role for T(3) as an inducer of oligodendrocyte progenitor cells in adult mouse brain following chronic demyelination.


Subject(s)
Demyelinating Diseases/diagnosis , Demyelinating Diseases/drug therapy , Diffusion Magnetic Resonance Imaging , Recovery of Function/drug effects , Thyroid Hormones/therapeutic use , Triiodothyronine/therapeutic use , Animals , Brain Mapping , Carbonic Anhydrase II/metabolism , Chronic Disease , Cuprizone , Demyelinating Diseases/chemically induced , Disease Models, Animal , Female , Hedgehog Proteins/metabolism , Leukocyte Common Antigens/metabolism , Mice , Mice, Inbred C57BL , Microscopy, Electron, Transmission , Myelin Sheath/metabolism , Myelin Sheath/ultrastructure , Nerve Tissue Proteins/metabolism , Neural Cell Adhesion Molecule L1/metabolism , Proliferating Cell Nuclear Antigen/metabolism , Sialic Acids/metabolism , Time Factors , Triiodothyronine/blood
7.
J Neurosci Res ; 85(5): 935-44, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17278151

ABSTRACT

The effect of a proteolipid protein (PLP) mutation on the developing white matter anisotropy was examined by diffusion tensor magnetic resonance imaging (DT-MRI) in a noninvasive study of a mouse model of Pelizaeus-Merzbacher disease (PMD). The jimpy PLP mutation in mice produces an irreversible dysmyelination in jimpy males, whereas heterozygous females exhibit a transient hypomyelination, as assessed by a longitudinal study of the same mice during development. Modifications of the different individual DT-MRI parameters were highlighted by specific changes in tissue structures caused by the mutation that includes the hypomyelination, axonal abnormalities, and recovery. Astrocytic hypertrophy is a striking cellular event in dysmyelinated jimpy brain, where most axons or bundles of fibers are entirely wrapped by astrocyte cytoplasmic processes, so its influences on DT-MRI parameters in dysmyelination were examined for the first time. DT-MRI data of the jimpy brain were compared with those obtained from dysmyelination of (oligo-TTK) transgenic mice, induced by oligodendrocyte killing, which have a mild astrocyte hypertrophy (Jalabi et al., 2005), and from recovering jimpy females, which have reduced astrocyte hypertrophy. The unique morphological feature of astrocytes in jimpy males coupled with an increase in the water channel protein aquaporin 4 (AQP4) was found to facilitate the directional water diffusion in the white matter. In addition to the major changes of DT-MRI parameters in the two dysmyelinated mice caused by the myelin loss and axonal modifications, the amplified magnitude of radial and axial diffusions in jimpy males was attributed principally to the strongly pronounced astrocyte hypertrophy.


Subject(s)
Astrocytes/pathology , Brain/pathology , Diffusion Magnetic Resonance Imaging/methods , Hypertrophy/pathology , Nerve Fibers, Myelinated/pathology , Pelizaeus-Merzbacher Disease/pathology , Animals , Anisotropy , Aquaporin 4/metabolism , Brain/physiopathology , Disease Models, Animal , Female , Heterozygote , Male , Mice , Mice, Jimpy , Mice, Transgenic , Microscopy, Electron, Transmission , Myelin Sheath/pathology , Oligodendroglia/pathology , Pelizaeus-Merzbacher Disease/physiopathology , Sex Characteristics
8.
J Neurosci Res ; 83(3): 392-402, 2006 Feb 15.
Article in English | MEDLINE | ID: mdl-16397901

ABSTRACT

Diffusion tensor magnetic resonance imaging (DT-MRI) was applied for in vivo quantification of myelin loss and regeneration. A transgenic mouse line (Oligo-TTK) expressing a truncated form of the herpes simplex virus 1 thymidine kinase gene (hsv1-tk) in oligodendrocytes was studied along with two induced phenotypes of myelin pathology. Myelin loss and axonal abnormalities differentially affect values of DT-MRI parameters in the brain of transgenic mice. Changes in the anisotropy of the white matter were assessed by calculating and mapping the radial (D perpendicular) and axial (D parallel) water diffusion to axonal tracts and fractional anisotropy (FA). A significant increase in D perpendicular attributed to the lack of myelin was observed in all selected brain white matter tracts in dysmyelinated mice. Lower D parallel values were consistent with the histological observation of axonal modifications, including reduced axonal caliber and overexpression of neurofilaments and III beta-tubulin. We show clearly that myelination and axonal changes play a role in the degree of diffusion anisotropy, because FA was significantly decreased in dysmyelinated brain. Importantly, myelin reparation during brain postnatal development induced a decrease in the magnitude of D( perpendicular) and an increase in FA compared with the same brain before recovery. The progressive increase in D parallel values was attributed to the gain in normal axonal morphology. This regeneration was confirmed by the detection of enlarged oligodendrocyte population, newly formed myelin sheaths around additional axons, and a gradual increase in axonal caliber.


Subject(s)
Brain Diseases/pathology , Demyelinating Diseases/pathology , Diffusion Magnetic Resonance Imaging , Recovery of Function/physiology , Animals , Animals, Newborn , Anisotropy , Antiviral Agents/administration & dosage , Brain/cytology , Brain/drug effects , Brain/metabolism , Brain/pathology , Brain/virology , Brain Diseases/drug therapy , Brain Diseases/metabolism , Brain Diseases/virology , Brain Mapping , Demyelinating Diseases/drug therapy , Demyelinating Diseases/metabolism , Demyelinating Diseases/virology , Ganciclovir/administration & dosage , Image Processing, Computer-Assisted/methods , Immunohistochemistry/methods , Mice , Mice, Transgenic , Microscopy, Electron, Transmission/methods , Myelin Basic Protein/metabolism , Nerve Fibers, Myelinated/metabolism , Nerve Fibers, Myelinated/pathology , Nerve Fibers, Myelinated/ultrastructure , Oligodendroglia/metabolism , Oligodendroglia/pathology , Oligodendroglia/ultrastructure , Protein Serine-Threonine Kinases/genetics , Protein-Tyrosine Kinases/genetics , Recovery of Function/drug effects , Time Factors
9.
Opt Express ; 14(25): 12271-87, 2006 Dec 11.
Article in English | MEDLINE | ID: mdl-19529655

ABSTRACT

Time-resolved diffuse optical methods have been applied to detect hemodynamic changes induced by cerebral activity. We describe a near infrared spectroscopic (NIRS) reconstruction free method which allows retrieving depth-related information on absorption variations. Variations in the absorption coefficient of tissues have been computed over the duration of the whole experiment, but also over each temporal step of the time-resolved optical signal, using the microscopic Beer-Lambert law.Finite element simulations show that time-resolved computation of the absorption difference as a function of the propagation time of detected photons is sensitive to the depth profile of optical absorption variations. Differences in deoxyhemoglobin and oxyhemoglobin concentrations can also be calculated from multi-wavelength measurements. Experimental validations of the simulated results have been obtained for resin phantoms. They confirm that time-resolved computation of the absorption differences exhibited completely different behaviours, depending on whether these variations occurred deeply or superficially. The hemodynamic response to a short finger tapping stimulus was measured over the motor cortex and compared to experiments involving Valsalva manoeuvres. Functional maps were also calculated for the hemodynamic response induced by finger tapping movements.

10.
Appl Opt ; 44(10): 1942-7, 2005 Apr 01.
Article in English | MEDLINE | ID: mdl-15813530

ABSTRACT

Simulations based on diffusion theory that use a finite-element method and rely on an magnetic resonance imaging head model suggest that time-resolved diffuse optical techniques could provide information about the depth at which variations in perfusion take place and improve the detection of cortical activation. Experimental investigations were performed with sequentially driven picosecond laser diodes and an eight-channel time-correlated single-photon-counting detection system. The experimental results obtained for activation in the motor cortex, and for the Valsalva maneuver, confirm our assumptions and are in good agreement with the simulated data.


Subject(s)
Brain Mapping/methods , Cerebral Cortex/anatomy & histology , Cerebral Cortex/physiology , Evoked Potentials, Motor/physiology , Image Interpretation, Computer-Assisted/methods , Spectroscopy, Near-Infrared/methods , Tomography, Optical/methods , Algorithms , Computer Simulation , Humans , Magnetic Resonance Imaging/methods , Models, Neurological , Reproducibility of Results , Sensitivity and Specificity
11.
Appl Opt ; 42(16): 3313-20, 2003 Jun 01.
Article in English | MEDLINE | ID: mdl-12790484

ABSTRACT

We describe an experimental setup for time-resolved diffuse optical tomography that uses a seven-channel light guide to transmit scattered light to a streak camera. This setup permits the simultaneous measurement of the time profiles of photons reemitted at different boundary sites of the objects studied. The instrument, its main specifications, and detector-specific data analysis before image reconstruction are described. The instrumentation was tested with phantoms simulating biological tissue, and the absorption and reduced scattering images that were obtained are discussed.


Subject(s)
Optics and Photonics , Photography/instrumentation , Tomography , Scattering, Radiation
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