Fiber-based Probes for Electrophysiology, Photometry, Optical and Electrical Stimulation, Drug Delivery, and Fast-Scan Cyclic Voltammetry In Vivo.

Recording and modulation of neuronal activity enables the study of brain function in health and disease. While translational neuroscience relies on electrical recording and modulation techniques, mechanistic studies in rodent models leverage genetic precision of optical methods, such as optogenetics and imaging of fluorescent indicators. In addition to electrical signal transduction, neurons produce and receive diverse chemical signals which motivate tools to probe and modulate neurochemistry.

Imaging bioluminescence by detecting localized haemodynamic contrast from photosensitized vasculature.

Bioluminescent probes are widely used to monitor biomedically relevant processes and cellular targets in living animals. However, the absorption and scattering of visible light by tissue drastically limit the depth and resolution of the detection of luminescence. Here we show that bioluminescent sources can be detected with magnetic resonance imaging by leveraging the light-mediated activation of vascular cells expressing a photosensitive bacterial enzyme that causes the conversion of bioluminescent emission into local changes in haemodynamic contrast.

A different interpretation of the DIANA fMRI signal.

Direct detection of neural activity by functional magnetic resonance imaging (fMRI) has been a longstanding goal in neuroscience. A recent study argued that it is possible to detect neuroelectrical potentials using a specialized fMRI scanning approach the authors termed "direct imaging of neuronal activity" (DIANA). We implemented DIANA in anesthetized rats and measured responses to somatosensory stimulation, reproducing core findings of the original study.

Prospective evaluation of radiographic manifestations of tuberculosis in relationship with CD4 count in patients with HIV/AIDS.

A major risk factor to develop active tuberculosis (TB) is the infection with the human immunodeficiency virus (HIV). Chest radiography is the first-line imaging modality used to rule out TB. Coinfected individuals present often with atypical imaging patterns, due to the immunosuppression caused by the virus, making diagnosis difficult.

Simulation of intravoxel incoherent perfusion signal using a realistic capillary network of a mouse brain.

Purpose: To simulate the intravoxel incoherent perfusion magnetic resonance magnitude signal from the motion of blood particles in three realistic vascular network graphs from a mouse brain.

Methods: In three networks generated from the cortex of a mouse scanned by two-photon laser microscopy, blood flow in each vessel was simulated using Poiseuille's law. The trajectories, flow speeds and phases acquired by a fixed number of simulated blood particles during a Stejskal-Tanner bipolar pulse gradient scheme were computed.

Diffusion tensor imaging of the abdominal organs: Influence of oriented intravoxel flow compartments.

Water flow in partially oriented intravoxel compartments mimics an anisotropic fast-diffusion regime, which contributes to the signal attenuation in diffusion-weighted images. In the abdominal organs, this flow may reflect physiological fluid movements (eg, tubular urine flow in kidneys, or bile flow through the liver) and have a clinical relevance. This study investigated the influence of anisotropic intravoxel water flow on diffusion tensor imaging (DTI) of the abdominal organs.

Modulation of Fear and Arousal Behavior by Serotonin Transporter (5-HTT) Genotypes in Newly Hatched Chickens.

The serotonin transporter (5-HTT) plays a key role in regulating serotonergic transmission via removal of serotonin (5-hydroxytryptamine, 5-HT) from synaptic clefts. Alterations in 5-HTT expression and 5-HT transmission have been shown to cause changes to adult behavior including fear. The objective of the present study was to investigate the 5-HTT role in fear in birds at the very early stages of post-hatching life.

Intravoxel Incoherent Motion Analysis of Abdominal Organs: Application of Simultaneous Multislice Acquisition.

Purpose: The aim of this study was to systematically evaluate the accuracy of quantitative intravoxel incoherent motion (IVIM) analysis of the upper abdomen applying simultaneous multislice (SMS) diffusion-weighted imaging (DWI) to reduce acquisition time.

Materials And Methods: Diffusion-weighted imaging of parenchymal abdominal organs was performed in 8 healthy volunteers at 3 T using a standard DWI sequence (acceleration factor 1 [AF1]) and an SMS-accelerated echo planar imaging sequence with acceleration factors 2 and 3 (AF2/AF3). Intravoxel incoherent motion analysis was performed with a multistep algorithm for true diffusion coefficient (Dt), pseudodiffusion coefficient (D*), and fraction of perfusion (Fp) measured for the liver, kidney cortex and medulla, pancreas, spleen, and erector spinae muscle.

Intravoxel Incoherent Motion: Model-Free Determination of Tissue Type in Abdominal Organs Using Machine Learning.

Purpose: For diffusion data sets including low and high b-values, the intravoxel incoherent motion model is commonly applied to characterize tissue. The aim of the present study was to show that machine learning allows a model-free approach to determine tissue type without a priori assumptions on the underlying physiology.

Materials And Methods: In 8 healthy volunteers, diffusion data sets were acquired using an echo-planar imaging sequence with 16 b-values in the range between 0 and 1000 s/mm.

In-depth analysis of interreader agreement and accuracy in categorical assessment of brown adipose tissue in (18)FDG-PET/CT.

Purpose: To evaluate the interreader agreement of a three-tier craniocaudal grading system for brown fat activation and investigate the accuracy of the distinction between the three grades.

Materials And Methods: After IRB approval, 340 cases were retrospectively selected from patients undergoing (18)FDG-PET/CT between 2007 and 2015 at our institution, with 85 cases in each grade and 85 controls with no active brown fat. Three readers evaluated all cases independently.

Integrin-Targeted Hybrid Fluorescence Molecular Tomography/X-ray Computed Tomography for Imaging Tumor Progression and Early Response in Non-Small Cell Lung Cancer.

Integrins play an important role in tumor progression, invasion and metastasis. Therefore we aimed to evaluate a preclinical imaging approach applying ανβ3 integrin targeted hybrid Fluorescence Molecular Tomography/X-ray Computed Tomography (FMT-XCT) for monitoring tumor progression as well as early therapy response in a syngeneic murine Non-Small Cell Lung Cancer (NSCLC) model. Lewis Lung Carcinomas were grown orthotopically in C57BL/6 J mice and imaged in-vivo using a ανβ3 targeted near-infrared fluorescence (NIRF) probe.