A5001596439- Advanced MRI Techniques and Applications
- MRI in cancer diagnosis
- Advanced Neuroimaging Techniques and Applications
- Lanthanide and Transition Metal Complexes
- Functional Brain Connectivity Studies
- Cerebrovascular and Carotid Artery Diseases
- Cardiac Imaging and Diagnostics
- Electron Spin Resonance Studies
- Glioma Diagnosis and Treatment
- Ferroptosis and cancer prognosis
- Radiopharmaceutical Chemistry and Applications
- Medical Imaging Techniques and Applications
- Radiomics and Machine Learning in Medical Imaging
- Traumatic Brain Injury and Neurovascular Disturbances
- Cardiovascular Health and Disease Prevention
- Acute Ischemic Stroke Management
- Atomic and Subatomic Physics Research
- Medical Image Segmentation Techniques
- Optical Imaging and Spectroscopy Techniques
- Cardiovascular and Diving-Related Complications
- Gaussian Processes and Bayesian Inference
- Fluid Dynamics and Mixing
- NMR spectroscopy and applications
- RNA modifications and cancer
- Dementia and Cognitive Impairment Research
University of Nottingham
2020-2025
University of Oxford
2016-2025
Wellcome Centre for Integrative Neuroimaging
2016-2025
Nottingham Biomedical Research Centre
2021-2024
Queen's Medical Centre
2021-2024
Mansfield University
2021
Oxford BioMedica (United Kingdom)
2016
Science Oxford
2016
John Radcliffe Hospital
2007-2013
Institute of Biomedical Science
2013
Variational Bayes (VB) has been proposed as a method to facilitate calculations of the posterior distributions for linear models, by providing fast Bayesian inference estimating parameters factorized approximation distribution. Here VB nonlinear forward models with Gaussian additive noise is presented. In case noninformative priors parameter estimates obtained from this approach are identical those found via least squares. However, advantage lies in its formulation, which permits prior...
Abstract Accurate assessment of cerebral perfusion is vital for understanding the hemodynamic processes involved in various neurological disorders and guiding clinical decision‐making. This guidelines article provides a comprehensive overview quantitative imaging brain using multi‐timepoint arterial spin labeling (ASL), along with recommendations its acquisition quantification. A major benefit acquiring ASL data multiple label durations and/or post‐labeling delays (PLDs) being able to...
Abstract The accuracy of cerebral blood flow (CBF) estimates from arterial spin labeling (ASL) is affected by the presence both gray matter (GM) and white within any voxel. Recently a partial volume (PV) correction method for ASL has been demonstrated (Asllani et al. Magn Reson Med 2008; 60:1362–1371), where PV were used with local linear regression to separate GM signal. Here new multi‐inversion time proposed that exploits spatially regularized kinetic curve model analysis. different...
The original concept of the ischaemic penumbra suggested imaging regional cerebral blood flow and metabolism would be required to identify tissue that may benefit from intervention. Amide proton transfer magnetic resonance imaging, a chemical exchange saturation technique, has been used derive intracellular pH in preclinical stroke models proposed as metabolic marker penumbra. In this proof principle clinical study, we explored potential pH-weighted technique at tissue-level. Detailed...
Arterial spin labeling (ASL) has undergone significant development since its inception, with a focus on improving standardization and reproducibility of acquisition quantification. In community-wide effort towards robust reproducible clinical ASL image processing, we developed the software package ExploreASL, allowing standardized analyses across centers scanners. The procedures used in ExploreASL capitalize published processing advancements address challenges multi-center datasets...
Amide proton transfer (APT) imaging is a pH mapping method based on the chemical exchange saturation phenomenon that has potential for penumbra identification following stroke. The majority of literature thus far focused generating pH-weighted contrast using magnetization ratio asymmetry analysis instead quantitative mapping. In this study, widely used and model-based were both assessed APT data collected from healthy subjects (n = 2) hyperacute stroke patients 6, median time after onset 2...
The present study is the first to investigate whether cerebral blood flow in hippocampus relates aerobic fitness children. In particular, we used arterial spin labeling (ASL) perfusion MRI provide a quantitative measure of 73 7- 9-year-old preadolescent Indeed, was found relate greater hippocampus, independent age, sex, and hippocampal volume. Such results suggest improved microcirculation vasculature children with higher levels fitness. Further, may influence how brain regulates its...
The purpose of this study was to establish a normal range for the arterial arrival time (AAT) in whole-brain pulsed spin labeling (PASL) cerebral perfusion MRI. Healthy volunteers (N = 36, range: 20 35 years) provided informed consent participate study. AAT assessed multiple brain regions, using three-dimensional gradient and echo (GRASE) at 3.0 T, found be 641 ± 95, 804 91, 802 126, 935 108 ms temporal, parietal, frontal, occipital lobes, respectively. Mean gray matter 694 89 females 15),...
Abstract Arterial spin labeling (ASL) provides a noninvasive method to measure brain perfusion and is becoming an increasingly viable alternative more invasive MR methods due improvements in acquisition, such as the use of three‐dimensional GRASE readout. A potential source error ASL measurements signal arising from intravascular blood that destined for distal tissue. This typically suppressed using diffusion gradients many sequences. However, several problems exist with this approach,...
Arterial spin labeling (ASL) techniques are gaining popularity for visualizing and quantifying cerebral blood flow (CBF) in a range of patient groups. However, most ASL methods lack vessel-selective information, which is important the assessment collateral arterial supply to lesions. In this study, we explored use vessel-encoded pseudocontinuous (VEPCASL) with multiple postlabeling delays obtain individual quantitative CBF bolus arrival time maps each four main brain-feeding arteries...
Abnormal pH is a common feature of malignant tumors and has been associated clinically with suboptimal outcomes. Amide proton transfer magnetic resonance imaging (APT MRI) holds promise as means to noninvasively measure tumor pH, yet multiple factors collectively make quantification from APT MRI data challenging. The purpose this study was improve our understanding the biophysical sources altered signals in tumors. Combining
This study examined the associations of body mass index (BMI), waist-to-hip ratio (WHR), waist circumference (WC), and physical activity (PA) with gray matter cerebral blood flow (CBFGM) in older adults. Cross-sectional data was used from Irish Longitudinal Study on Ageing (n = 495, age 69.0 ±7.4 years, 52.1% female). Whole-brain CBFGM quantified using arterial spin labeling MRI. Results multivariable regression analysis revealed that an increase BMI 0.43 kg/m2, WHR 0.01, or WC 1.3 cm were...
The purpose of this study was to evaluate how cerebral blood flow and bolus arrival time (BAT) measures derived from arterial spin labeling (ASL) MRI data change for different hypercarbic gas stimuli. Pseudocontinuous ASL (pCASL) applied (3.0T; spatial resolution = 4 × 7 mm 3 ; repetition time/echo ( TR/TE) 3,600/11 ms) sequentially in healthy volunteers n 12; age 30±4 years) separate experiments which (i) normocarbic normoxia (i.e., room air), 5% CO 2 /21% O /74% N ), hyperoxia carbogen:...
Purpose Arterial spin labeling (ASL) MRI is a non‐invasive perfusion imaging technique that inherently SNR limited, so scan protocols ideally need to be rigorously optimized provide the most accurate measurements. A general framework presented for optimizing ASL experiments achieve optimal accuracy estimates and, if required, other hemodynamic parameters, within fixed time. The effectiveness of this then demonstrated by post‐labeling delays (PLDs) multi‐PLD pseudo‐continuous experiment and...
Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was investigate the effect of upon cerebral perfusion and cerebrovascular reactivity whether haemodynamic impairment is influenced at brain tissue level by existence primary and/or secondary collateral. Eighty-eight patients with ICA 29 healthy controls underwent MR examination. The presence collaterals determined time-of-flight,...
Electrophysiological and hemodynamic data can be integrated to accurately precisely identify the generators of abnormal electrical activity in drug-resistant focal epilepsy. Arterial Spin Labeling (ASL), a magnetic resonance imaging (MRI) technique for quantitative noninvasive measurement cerebral blood flow (CBF), provide direct measure variations perfusion associated with epileptic focus. In this study, we aimed confirm ASL diagnostic value identification epileptogenic zone, as compared...
Amide proton transfer (APT) imaging may help identify the ischaemic penumbra in stroke patients, classical definition of which is a region tissue around core that hypoperfused and metabolically stressed. Given potential APT to complement existing techniques provide clinically-relevant information, there need develop analysis deliver robust repeatable metric. The challenge accurate quantification an metric has been heterogeneous in-vivo environment human tissue, exhibits several confounding...