Basal forebrain volume reliably predicts the cortical spread of Alzheimer's degeneration.

Alzheimer's disease neurodegeneration is thought to spread across anatomically and functionally connected brain regions. However, the precise sequence of spread remains ambiguous. The prevailing model used to guide in vivo human neuroimaging and non-human animal research assumes that Alzheimer's degeneration starts in the entorhinal cortices, before spreading to the temporoparietal cortex.

Free Water in White Matter Differentiates MCI and AD From Control Subjects.

Recent evidence shows that neuroinflammation plays a role in many neurological diseases including mild cognitive impairment (MCI) and Alzheimer's disease (AD), and that free water (FW) modeling from clinically acquired diffusion MRI (DTI-like acquisitions) can be sensitive to this phenomenon. This FW index measures the fraction of the diffusion signal explained by isotropically unconstrained water, as estimated from a bi-tensor model. In this study, we developed a simple but powerful whole-brain FW measure designed for easy translation to clinical settings and potential use as a priori outcome measure in clinical trials.

Immunotherapy with ponezumab for probable cerebral amyloid angiopathy.

Objective: Cerebral amyloid angiopathy (CAA) is caused by cerebrovascular deposition of -amyloid fragments leading to cerebrovascular dysfunction and other brain injuries. This phase 2, randomized, double-blind trial in patients with probable CAA assessed the efficacy and safety of ponezumab, a novel monoclonal antibody against A .

Methods: Thirty-six participants aged 55-80 years with probable CAA received intravenous placebo ( = 12) or ponezumab ( = 24).

The role of fMRI in drug development.

Functional magnetic resonance imaging (fMRI) has been known for over a decade to have the potential to greatly enhance the process of developing novel therapeutic drugs for prevalent health conditions. However, the use of fMRI in drug development continues to be relatively limited because of a variety of technical, biological, and strategic barriers that continue to limit progress. Here, we briefly review the roles that fMRI can have in the drug development process and the requirements it must meet to be useful in this setting.

Dynamic-contrast-enhanced-MRI with extravasating contrast reagent: rat cerebral glioma blood volume determination.

The accurate mapping of the tumor blood volume (TBV) fraction (vb) is a highly desired imaging biometric goal. It is commonly thought that achieving this is difficult, if not impossible, when small molecule contrast reagents (CRs) are used for the T1-weighted (Dynamic-Contrast-Enhanced) DCE-MRI technique. This is because angiogenic malignant tumor vessels allow facile CR extravasation.

Dynamic MRI using iron oxide nanoparticles to assess early vascular effects of antiangiogenic versus corticosteroid treatment in a glioma model.

The vascular effects of antiangiogenic treatment may pose problems for evaluating brain tumor response based on contrast-enhanced magnetic resonance imaging (MRI). We used serial dynamic contrast-enhanced MRI at 12 T to assess vascular responses to antiangiogenic versus steroid therapy. Athymic rats with intracerebral U87MG human glioma (n=17) underwent susceptibility-weighted perfusion MRI with ferumoxytol, a solely intravascular ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle, followed by T1-weighted dynamic gadodiamide-enhanced MRI to measure vascular permeability.

Influence of atmospheric and sea-surface corrections on retrieval of bottom depth and reflectance using a semi-analytical model: a case study in Kaneohe Bay, Hawaii.

Hyperspectral instruments provide the spectral detail necessary for extracting multiple layers of information from inherently complex coastal environments. We evaluate the performance of a semi-analytical optimization model for deriving bathymetry, benthic reflectance, and water optical properties using hyperspectral AVIRIS imagery of Kaneohe Bay, Hawaii. We examine the relative impacts on model performance using two different atmospheric correction algorithms and two different methods for reducing the effects of sunglint.

Cs + ADC in rat brain decreases markedly at death.

Spectroscopic resolution of intracellular and extracellular compartments can be used to probe the kinetic environment of those spaces and the compartment-specific changes that occur following injury. This is important for understanding the biophysical mechanisms that underlie the remarkable diffusion-weighted MRI contrast of injured central nervous system (CNS) tissue. Cesium-133 is a physiologic analog of potassium that is actively taken up by cells and resides primarily in the intracellular space.

Sodium ion apparent diffusion coefficient in living rat brain.

The apparent diffusion coefficient (ADC) of Na(+) was determined in live rat brain. The brain extracellular-to-intracellular Na(+) content ratio is approximately 8:2, which is the inverse of that for water in these spaces. Consequently, the ADC of Na(+) is primarily affected by motion in the extracellular space, and Na(+) can be viewed as a reporter molecule for motion in that space.