Brain Imaging
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Susceptibility Tensor Imaging (STI)
STI is a new MRI”technology in development. It consists on creating images and contrast based on the susceptibility of the tissue to the magnetic field. This susceptibility seems to be based to the anisotropic alignment of the molecules. The tissue ismore susceptible when the angle to the magnetic field is smaller. A recent study in Continue reading
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Transcranial Doppler (TCD)
TCD is the only non-invasive real-time neuroimaging study that can evaluate the characteristics of cerebral blood flow continuously. CT Angiography (CTA ) and Magnetic Resonance Angiography (MRA ) can do snapshots in time. Fluoroscopic angiography is the gold standard and can be used as a confirmatory tool. Some of the applications of TCD are: stroke, vasomotor reactivity Continue reading
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Magnetic Resonance Force Microscopy (MRFM)
Very impressive advancements have been made in this field. The goal is ultimately to visualize matter at the molecular and atomic level. This of course will resolve and hopefully prove many of the questions and mysteries of atomic physics. Ultrahigh resolution 3D images are currently available and they promise to continue to improve. The key Continue reading
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Diffusion MRI Tractography as a diagnostic tool for Brain Pathology
Diffusion MRI tractography can be used to evaluate for brain pathology by measuring for pathlength, for example. The pathlength constitutes neuronal brain connectivity between two specified brain locations. An abnormal pathlength could be increased or decreased. A significant change in pathlength should point to a specific brain pathology depending on the location of the path. Continue reading
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Diffraction Enhanced Imaging (DEI)
This is a relatively new imaging technology that uses three “physical mechanisms” to generate contrast. Those mechanisms are: 1) X-Ray absorption, 2) Refraction, 3) Ultra small angle scatter rejection. This technology can produce high contrast images with much lower radiation dose compared to conventional radiography. One of the applications this technique might be useful for Continue reading
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Track Density Imaging (TDI)
When using MRI, in order to increase spatial resolution we need a longer acquisition time. We also need the same to increase signal to noise ratio (SNR). High tesla MRI, although it increases SNR, it has a problem with deep penetration called the skin effect. Deep structures might be difficult to visualize. A new post-processing Continue reading
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Magnetic Resonance Elastography
The elastic properties of human tissues have been evaluated in a clinical setting by palpation. Although this procedure has often helped clinical diagnosis, it is a subjective procedure and cannot be quantified. More recently a quantifiable technique has been developed using imaging technologies such as MRI, Ultrasound, Optical Imaging and so forth, whereby the degree Continue reading
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Mapping the Mind
As I mentioned on previous blog entries, I believe the brain and the mind overlap to some degree but also there should be a free brain area without mind and a free mind area without brain. Because our medications act on the brain but not on the mind itself, our knowledge of this interface is Continue reading
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Measures of Cortical Brain Thickness
Anatomical MRI measures of cortical brain thickness have been recently evaluated. In normal aging there is a decrease in cortical thickness, which presents an anterior-posterior gradient, being more prominent in Frontal and Parietal than in Temporal and Occipital lobes. There are regional differences between both sexes. In Alzheimer’s disease the reduction in cortical thickness is Continue reading
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Nanoantibodies
Nanoantibodies also known as nanobodies, have advantage over full size antibodies that they are more stable, aggregate less, and they can penetrate very small locations. There are currently attempts to make them cross the blood brain barrier ( BBB ). An idea that I suggest is to bind a nanobody to a nanoparticle, so the Continue reading
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Selective Plane Illumination Microscopy
This new technique has the advantage of visualizing in vivo tissues, in real time and at very high resolution. It can visualize cellular events that have fluorescence. It is technically very similar to fluorescence microscopy, but the beam of light comes from the side, thereby generating a selective plane illumination that is captured by a Continue reading
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Multispectral Optoacustic Tomography (MSOT)
MSOT uses the photoacoustic principle I explained in a previous blog entry. With this technique one is able to visualize in vivo cellular events with high sensitivity, at a resolution of 100 micrometers. It has a big advantage of being able to visualize physiology and anatomy at the same time without combining two different technologies. It is also Continue reading
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Microscopic Diffusion Tensor Imaging
Resolution is always a limitation when detailed analysis of the brain anatomy is needed. A partial solution for this problem is the use of Microscopic Diffusion Tensor Imaging. Diffusion Tensor Imaging (DTI) is an MRI technique that displays the white matter tracts by using the diffusion of water as a technique. The applicability of this Continue reading
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Near-Infrared Spectroscopy (NIRS)
This technique consists of a light emitting diode and two distant sensors attached to the fronto-parietal side of the skull. The concentration of oxygen is calculated by the differential signal between these two sensors. NIRS is used in neonates for the evaluation of the concentration of oxygen and hemoglobin. In consequence it can evaluate the Continue reading
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Imaging Neuroinflammation
The benzodiazepine receptor on the mitochondria of activated microglia constitutes a biomarker for neuroinflammation. The PET radiotracer C11-PK11195 binds to this receptor, making the use of brain images a key diagnostic tool in disease states characterized by neuroinflammation. Alzheimer’s disease (AD) and Multiple Sclerosis (MS) are two such conditions. There has been a debate if Continue reading
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Fluorescence Molecular Tomography with Computed Tomography (FMT-CT)
FMT-CT is a new method of fluorescence imaging. It allows image quantification in vivo. Fluorescence imaging has an advantage over PET that it allows non-ionizing radiation to be used, does not need a cyclotron, and it allows the simultaneous comparison of multiple biomarkers. The problem with FMT alone is that there is difficulty with anatomical Continue reading
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Imaging the Blood-Brain Barrier (BBB)
Relatively hydrophilic and/or big molecules have difficulty in crossing the BBB. This hurdle has kept many promising drug treatments on the sidelines because they cannot reach their target. The same applies for certain radiotracers in brain imaging. In order to overcome this problem Nanoparticles (NP) that target specific transport mechanisms in the BBB are in Continue reading
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Neuroimaging is useful to assess Neural Stem Cell Implantation
MRI can characterize neural stem cell implantation by assessing the migration, proliferation and location. This can be achieved by labeling the neuronal “stem cells” with Iron, which can be observed with MRI. After the cells are implanted we see that the concentration of cells diminishes in the implantation area and increases in the final location Continue reading
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Association between White Matter Ischemia (WMI) and Carotid Plaque Morphology
In a recent study by Patterson AJ, etal. the above relationship was evaluated. Carotid Plaque morphology as evaluated with High resolution in vivo MRI shows that certain plaque characteristics such as- thin or ruptured fibrous caps, large necrotic lipid core or intraplaque hemorrhage may be associated with thromboembolic Stroke. The question they had was if WMI is related to Continue reading
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Near Infrared Fluorescence Imaging
The use of near infrared light has the advantage of photon penetration. This kind of light is used in near infrared fluorescence imaging. Because there is little NIR fluorescence contrast generated by most tissues, most in vivo studies administer exogenous contrast agents. In relation to the brain, this technique can be used to map the Continue reading
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EEG and fMRI Fusion
EIt has been shown that when evaluating for the time sequence of brain events, either EEG or fMRI can be inadequate. EEG is known for its high temporal resolution. fMRI is known for its high spatial resolution when compared to EEG. EEG will provide the electrical activity information and fMRI the hemodynamic information. It would Continue reading
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Stereology
New insights await by comparing the findings of neural tracing done with Stereology to results obtained with Diffusion Tensor Imaging. Stereology originated in the 1700’s with the discovery of an association between geometry and probability by Buffon in 1733. But there were problems applying this method to inhomogeneous structures. This issue was overcome with Design-Based Continue reading
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Reliability of Quantitative Diffusion Tensor Tractography
MRI Difussion Tensor Imaging has been used to evaluate for structural brain connectivity lately, a technique that has been traditionally done using pathological methods. DTI is based on water diffusion along the brain fiber tracts. The complexity of the brain fibers is a challenge. In a recent study by Wang YV. et al ( A Continue reading
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Magnetic Resonance Electrical Impedance Tomography (MREIT)
This is a relatively new technology in development that is based on injecting current through surface electrodes into the human body. This current will induce a magnetic flux that relates to the conductivity of the tissue. MRI will then capture this magnetic flux. This technology shows a high resolution within a few millimetres. The SNR (signal to noise Continue reading
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Susceptibility Tensor Imaging (STI)
STI is a new MRI”technology in development. It consists on creating images and contrast based on the susceptibility of the tissue to the magnetic field. This susceptibility seems to be based to the anisotropic alignment of the molecules. The tissue is more susceptible when the angle to the magnetic field is smaller. A recent study in Continue reading
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Transcranial Doppler (TCD)
TCD is the only non-invasive real-time neuroimaging study that can evaluate the characteristics of cerebral blood flow continuously. CT Angiography (CTA ) and Magnetic Resonance Angiography (MRA ) can do snapshots in time. Fluoroscopic angiography is the gold standard and can be used as a confirmatory tool. Some of the applications of TCD are: stroke, vasomotor reactivity testing, Continue reading

