Mapping short association fibre connectivity up to V3 in the human brain in vivo.

Short association fibres (SAF) are the most abundant fibre pathways in the human white matter. Until recently, SAF could not be mapped comprehensively in vivo because diffusion weighted magnetic resonance imaging with sufficiently high spatial resolution needed to map these thin and short pathways was not possible. Recent developments in acquisition hardware and sequences allowed us to create a dedicated in vivo method for mapping the SAF based on sub-millimetre spatial resolution diffusion weighted tractography, which we validated in the human primary (V1) and secondary (V2) visual cortex against the expected SAF retinotopic order.

Improving MR axon radius estimation in human white matter using spiral acquisition and field monitoring.

Purpose: To compare MR axon radius estimation in human white matter using a multiband spiral sequence combined with field monitoring to the current state-of-the-art echo-planar imaging (EPI)-based approach.

Methods: A custom multiband spiral sequence was used for diffusion-weighted imaging at ultra-high -values. Field monitoring and higher order image reconstruction were employed to greatly reduce artifacts in spiral images.

Brain structure and function: a multidisciplinary pipeline to study hominoid brain evolution.

To decipher the evolution of the hominoid brain and its functions, it is essential to conduct comparative studies in primates, including our closest living relatives. However, strong ethical concerns preclude neuroimaging of great apes. We propose a responsible and multidisciplinary alternative approach that links behavior to brain anatomy in non-human primates from diverse ecological backgrounds.

High-resolution quantitative and functional MRI indicate lower myelination of thin and thick stripes in human secondary visual cortex.

The characterization of cortical myelination is essential for the study of structure-function relationships in the human brain. However, knowledge about cortical myelination is largely based on post-mortem histology, which generally renders direct comparison to function impossible. The repeating pattern of pale-thin-pale-thick stripes of cytochrome oxidase (CO) activity in the primate secondary visual cortex (V2) is a prominent columnar system, in which histology also indicates different myelination of thin/thick versus pale stripes.

Quantitative MRI maps of human neocortex explored using cell type-specific gene expression analysis.

Quantitative magnetic resonance imaging (qMRI) allows extraction of reproducible and robust parameter maps. However, the connection to underlying biological substrates remains murky, especially in the complex, densely packed cortex. We investigated associations in human neocortex between qMRI parameters and neocortical cell types by comparing the spatial distribution of the qMRI parameters longitudinal relaxation rate (${R_{1}}$), effective transverse relaxation rate (${R_{2}}^{\ast }$), and magnetization transfer saturation (MTsat) to gene expression from the Allen Human Brain Atlas, then combining this with lists of genes enriched in specific cell types found in the human brain.

-correction of magnetization transfer saturation maps optimized for 7T postmortem MRI of the brain.

Purpose: Magnetization transfer saturation ( ) is a useful marker to probe tissue macromolecular content and myelination in the brain. The increased -inhomogeneity at  T and significantly larger saturation pulse flip angles which are often used for postmortem studies exceed the limits where previous correction methods are applicable. Here, we develop a calibration-based correction model and procedure, and validate and evaluate it in postmortem 7T data of whole chimpanzee brains.

Error quantification in multi-parameter mapping facilitates robust estimation and enhanced group level sensitivity.

Multi-Parameter Mapping (MPM) is a comprehensive quantitative neuroimaging protocol that enables estimation of four physical parameters (longitudinal and effective transverse relaxation rates R and R, proton density PD, and magnetization transfer saturation MT) that are sensitive to microstructural tissue properties such as iron and myelin content. Their capability to reveal microstructural brain differences, however, is tightly bound to controlling random noise and artefacts (e.g.

Combining navigator and optical prospective motion correction for high-quality 500 μm resolution quantitative multi-parameter mapping at 7T.

Purpose: High-resolution quantitative multi-parameter mapping shows promise for non-invasively characterizing human brain microstructure but is limited by physiological artifacts. We implemented corrections for rigid head movement and respiration-related B0-fluctuations and evaluated them in healthy volunteers and dementia patients.

Methods: Camera-based optical prospective motion correction (PMC) and FID navigator correction were implemented in a gradient and RF-spoiled multi-echo 3D gradient echo sequence for mapping proton density (PD), longitudinal relaxation rate (R1) and effective transverse relaxation rate (R2*).

The variability of MR axon radii estimates in the human white matter.

The noninvasive quantification of axonal morphology is an exciting avenue for gaining understanding of the function and structure of the central nervous system. Accurate non-invasive mapping of micron-sized axon radii using commonly applied neuroimaging techniques, that is, diffusion-weighted MRI, has been bolstered by recent hardware developments, specifically MR gradient design. Here the whole brain characterization of the effective MR axon radius is presented and the inter- and intra-scanner test-retest repeatability and reproducibility are evaluated to promote the further development of the effective MR axon radius as a neuroimaging biomarker.

Mapping Short Association Fibers in the Early Cortical Visual Processing Stream Using In Vivo Diffusion Tractography.

Short association fibers (U-fibers) connect proximal cortical areas and constitute the majority of white matter connections in the human brain. U-fibers play an important role in brain development, function, and pathology but are underrepresented in current descriptions of the human brain connectome, primarily due to methodological challenges in diffusion magnetic resonance imaging (dMRI) of these fibers. High spatial resolution and dedicated fiber and tractography models are required to reliably map the U-fibers.

Biophysically motivated efficient estimation of the spatially isotropic component from a single gradient-recalled echo measurement.

Purpose: To propose and validate an efficient method, based on a biophysically motivated signal model, for removing the orientation-dependent part of using a single gradient-recalled echo (GRE) measurement.

Methods: The proposed method utilized a temporal second-order approximation of the hollow-cylinder-fiber model, in which the parameter describing the linear signal decay corresponded to the orientation-independent part of . The estimated parameters were compared to the classical, mono-exponential decay model for in a sample of an ex vivo human optic chiasm (OC).

Leading the integration of physician associates into the UK health workforce.

The introduction of physician associates into the UK health workforce is one of the most significant examples of potentially disruptive innovation in many years, and lessons can be learned from research into the introduction of advanced nurse practitioners. Positive, forward-looking health-care leadership is required at all levels to ensure the successful integration of physician associates into the UK workforce. This review found that organizational culture had an enormous impact on the introduction of advanced nurse practitioners and likewise will affect the integration of physician associates.

Microstructural imaging of human neocortex in vivo.

The neocortex of the human brain is the seat of higher brain function. Modern imaging techniques, chief among them magnetic resonance imaging (MRI), allow non-invasive imaging of this important structure. Knowledge of the microstructure of the neocortex has classically come from post-mortem histological studies of human tissue, and extrapolations from invasive animal studies.

NODDI-DTI: Estimating Neurite Orientation and Dispersion Parameters from a Diffusion Tensor in Healthy White Matter.

The NODDI-DTI signal model is a modification of the NODDI signal model that formally allows interpretation of standard single-shell DTI data in terms of biophysical parameters in healthy human white matter (WM). The NODDI-DTI signal model contains no CSF compartment, restricting application to voxels without CSF partial-volume contamination. This modification allowed derivation of analytical relations between parameters representing axon density and dispersion, and DTI invariants (MD and FA) from the NODDI-DTI signal model.

Coexisting depressive symptoms do not limit the benefits of chronic neuromodulation: A study of over 200 patients.

Aims: To examine the relationship between coexisting depressive symptoms and outcomes after staged neuromodulation procedures for refractory urological symptoms.

Methods: Adults who enrolled in a prospective database and completed a Personal Health Questionnaire Depression Scale (PHQ-8) at baseline were reviewed. The PHQ-8 and Generalized Anxiety Disorder (GAD-7) assessed depressive/anxiety symptoms pre and 6 months post device implant.

Completely Isolated Retroperitoneal Enteric Duplication Cyst with Adenocarcinoma Transformation Managed with Robotic Radical Nephrectomy.

Enteric duplication cysts are congenital malformations that typically affect children in infancy, but can also affect adults. Rarely, these cysts can be complicated by malignancy. We present the first case of retroperitoneal duplication cyst that was complicated by malignancy transformation and managed by robot-assisted excision.

Conformational analysis of small organic molecules using NOE and RDC data: A discussion of strychnine and α-methylene-γ-butyrolactone.

To understand the properties and/or reactivity of an organic molecule, an understanding of its three-dimensional structure is necessary. Simultaneous determination of configuration and conformation often poses a daunting challenge. Thus, the more information accessible for a given molecule, the better.

A Standardised Vocabulary for Identifying Benthic Biota and Substrata from Underwater Imagery: The CATAMI Classification Scheme.

Imagery collected by still and video cameras is an increasingly important tool for minimal impact, repeatable observations in the marine environment. Data generated from imagery includes identification, annotation and quantification of biological subjects and environmental features within an image. To be long-lived and useful beyond their project-specific initial purpose, and to maximize their utility across studies and disciplines, marine imagery data should use a standardised vocabulary of defined terms.

Every ward is a 'Nut Island'? Preventing good health-care teams 'going bad'.

This article explores how Levy's 'Nut Island effect' can be used to help identify health-care teams at risk of becoming isolated, disenchanted and separated physically and psychologically from senior management. Such isolation can lead to disastrous effects.

Predictors of incisional hernia after robotic assisted radical prostatectomy.

Introduction. To explore the long term incidence and predictors of incisional hernia in patients that had RARP. Methods.

Quantum mechanical NMR simulation algorithm for protein-size spin systems.

Nuclear magnetic resonance spectroscopy is one of the few remaining areas of physical chemistry for which polynomially scaling quantum mechanical simulation methods have not so far been available. In this communication we adapt the restricted state space approximation to protein NMR spectroscopy and illustrate its performance by simulating common 2D and 3D liquid state NMR experiments (including accurate description of relaxation processes using Bloch-Redfield-Wangsness theory) on isotopically enriched human ubiquitin - a protein containing over a thousand nuclear spins forming an irregular polycyclic three-dimensional coupling lattice. The algorithm uses careful tailoring of the density operator space to only include nuclear spin states that are populated to a significant extent.

Simulation of coherence selection by pulsed field gradients in liquid-state NMR using an auxiliary matrix formalism.

An algorithm for simulating coherence selection due to a pulse sequence element consisting of two pulsed field gradients separated by a short collection of pulses and delays is introduced. This algorithm involves computation of the matrix exponential of an auxiliary matrix twice the size of the system Liouvillian, a dimensional increase smaller than is required with other known computational methods. Approximations valid for most simulations of liquid-state NMR spectra are involved in the derivation.