Tom Roberts

• PhD
• Research Associate at King's College London

Purpose To investigate the potential of continuous radiofrequency (RF) shifting (SWEEP) as a technique for creating densely sampled data while maintaining a stable signal state for dynamic imaging. Methods We present a method where a continuous stable state of magnetization is swept smoothly across the anatomy of interest, creating an efficient ap...

The permeability of cell membranes varies significantly across both healthy and diseased tissue, and changes in cell membrane permeability can occur during treatment response in tumours. Measurements of cell membrane permeability could therefore be useful for tumour detection and as biomarkers of treatment response in the clinic. As the diffusion o...

The emergence of multiparametric diffusion models combining diffusion and relaxometry measurements provides powerful new ways to explore tissue microstructure, with the potential to provide new insights into tissue structure and function. However, their ability to provide rich analyses and the potential for clinical translation critically depends o...

Understanding the uptake of a drug by diseased tissue, and the drug’s subsequent spatiotemporal distribution, are central factors in the development of effective targeted therapies. However, the interaction between the pathophysiology of diseased tissue and individual therapeutic agents can be complex, and can vary across tissue types and across su...

We demonstrate the feasibility of measuring diffusion exchange using Diffusion Exchange Spectroscopy (DEXSY), in yeast. We show data acquired from yeast suspensions with a 9.4 T Varian scanner using two different sets of DEXSY scan parameters in order to probe different diffusion lengths.

The emergence of multiparametric diffusion models combining diffusion and relaxometry measurements provide powerful new ways to explore tissue microstructure with the potential to provide new insights into tissue structure and function. However, their ability to provide rich analyses and the potential for clinical translation critically depends on...

INTRODUCTION VERDICT (Vascular, Extracellular, and Restricted Diffusion for Cytometry in Tumours) MRI is a diffusion imaging technique which gives information about tumour microstructure beyond ADC measures and structural imaging. VERDICT uses a three-compartment mathematical model to estimate tissue parameters such as cell density, radius and vasc...

Several distinct fluid flow phenomena occur in solid tumors, including intravascular blood flow and interstitial convection. Interstitial fluid pressure is often raised in solid tumors, which can limit drug delivery. To probe low-velocity flow in tumors resulting from raised interstitial fluid pressure, we developed a novel MRI technique named conv...

Several distinct fluid flow phenemena occur in solid tumours, including intravascular blood flow and interstitial convection. To probe low-velocity flow in tumors resulting from raised interstitial fluid pressure, we have developed a novel magnetic resonance imaging (MRI) technique named convection-MRI. It uses a phase-contrast acquisition with a d...

The cover image, by Thomas A. Roberts et al., is based on the Research Article Direct comparison of high-temporal-resolution CINE MRI with Doppler ultrasound for assessment of diastolic dysfunction in mice, DOI: 10.1002/nbm.3763.

Supplementary Video S1: Example standard CINE movie from a basal slice location in a normal mouse. (Supplementary_Video_S1_Normal_20frames.avi)

Supplementary Video S2: Example standard CINE movie from a basal slice location in an infarcted mouse. (Supplementary_Video_S2_Infarct_20frames.avi)

Figure S1 Supporting info item

Figure S2 Supporting info item

There has been slow progress in the development of new therapeutic strategies for treating brain tumours, partly because assessment of treatment response is difficult and largely reliant on simple bi-dimensional measurements of MRI contrast-enhancing regions. Hence, there is a clinical need to develop improved imaging techniques for monitoring trea...

Diastolic dysfunction is a sensitive early indicator of heart failure and can provide additional data to conventional measures of systolic function. Transmitral Doppler ultrasound, which measures the one-dimensional flow of blood through the mitral valve, is currently the preferred method for the measurement of diastolic function, but the measureme...

Introduction Information on myocardial viability is important for the management of ischaemic cardiomyopathy patient. Difficulties in assessing viability arise because necrotic tissue and viable myocardium overlap at the infarct border zone. Manganese-enhanced MRI (MEMRI) is sensitive to viability and the inotropic state of the heart¹. Mn²⁺ enters...

T2-weighted cardiovascular magnetic resonance (T2-CMR) of myocardial edema can quantify the area-at-risk (AAR) following acute myocardial infarction (AMI), and has been used to assess myocardial salvage by new cardioprotective therapies. However, some of these therapies may reduce edema, leading to an underestimation of the AAR by T2-CMR. Here, we...

In this study, we use VERDICT (Vascular, Extracellular and Restricted Diffusion for Cytometry in Tumours) MRI to assess longitudinal changes in the microstructure of a mouse model of glioma (GL261), following treatment with Temozolomide, an alkylating chemotherapeutic agent. VERDICT estimates of cell radius and intracellular volume fraction decreas...

VERDICT (Vascular, Extracellular, and Restricted Diffusion for Cytometry in Tumours) MRI is a diffusion imaging technique which has shown promise in revealing information about tumour microstructure beyond ADC measures and structural imaging. We report the first application of VERDICT to human brain tumours. In this feasibility study, we characteri...

100 Word Synopsis: We report the development of a novel in silico modelling framework for probing the in vivo diffusion MRI signal in tumours, based on high-resolution (5-10µm) optical imaging data from complete tumours. Blood flow in tissue substrates was estimated using fluid dynamical modelling. We then simulated the MRI signal using a Monte Car...

Here, we use numerical simulations to demonstrate the feasibility of measuring diffusion exchange across the cell membrane using DEXSY (Diffusion Exchange spectroscopy) and compare it with FEXSY (Filter Exchange Spectroscopy). Simulations were carried out using the CAMINO platform, for a range of permeabilities, in a substrate chosen to model nerve...

β-thalassemia (βT) is a genetic blood disorder causing profound and life threatening anemia. Current clinical management of βT is a lifelong dependence on regular blood transfusions, a consequence of which is systemic iron overload leading to acute heart failure. Recent developments in gene and chelation therapy give hope of better prognosis for pa...

Background: Research using orthotopic and transgenic models of cancer requires imaging methods to non-invasively quantify tumour burden. As the choice of appropriate imaging modality is wide-ranging, this study aimed to compare low-field (1T) magnetic resonance imaging (MRI), a novel and relatively low-cost system, against established preclinical...

It has previously been shown that compartmental models of tissue diffusion such as VERDICT can enable access to useful measures of in-vivo tumour microstructure such as cell radius. However, comparing the in-vivo values with those measured from histology showed that a discrepancy exists between the two; histological values were consistently smaller...

Stimuli-responsive nanoprobes that combine both fluorescence and magnetic resonance imaging (MRI) are anticipated to be highly beneficial for tumor visualization with high imaging sensitivity. By employing an interfacial templating scheme, a pH-activatable fluorescence/MRI dual-modality imaging nanoprobe is successfully developed based on the coenc...

Common measures of systolic cardiac function often fail to detect heart failure. Many patients present with preserved ejection fraction despite underlying pathology. Therefore, a more sensitive measure of heart failure is required. In this study, a high-temporal resolution (HTR-) CINE sequence (approximately one frame every millisecond) is presente...

Rationale In order to assess the cardioprotective efficacy of a novel therapy for reducing myocardial infarct (MI) size, a reliable in vivo measure of the area-at-risk (AAR) is required. Although T2-weighted cardiac MRI (T2-MRI), which detects myocardial oedema, has been used to measure the AAR, some cardioprotective therapies have been found to re...

Mouse embryo imaging is conventionally carried out on ex vivo embryos excised from the amniotic sac, omitting vital structures and abnormalities external to the body. Here, we present an in amnio MR imaging methodology in which the mouse embryo is retained in the amniotic sac and demonstrate how important embryonic structures can be visualised in 3...

Purpose: Novel therapeutic strategies are required to protect the heart against acute ischaemia-reperfusion injury (IRI). Assessing their cardioprotective efficacy requires measurement of infarct size (IS) and the "area-at-risk (AAR). T2-weighted cardiac magnetic resonance imaging (cMR) can delineate the AAR in vivo by detecting areas of oedema fol...

Significance How cardiac and skeletal muscle function is maintained and regulated is important in terms of understanding normal muscle physiology and muscle-based disease (myopathy). The two striated muscle types are structurally and functionally divergent, suggesting alternate molecular regulation. However, our discovery that the transcription fac...

Rodent models of abdominal wall defects (AWD) may provide insight into the pathophysiology of these conditions including gut dysfunction in gastroschisis, or pulmonary hypoplasia in exomphalos. Previously, a Scribble mutant mouse model (circletail) was reported to exhibit gastroschisis. We further characterise this AWD in Scribble knockout mice. Ho...

Healthcare-associated infections (HCAI/HAI) represent a substantial threat to patient health during hospitalization and incur billions of dollars additional cost for subsequent treatment. One promising method for the detection of bacterial contamination in a clinical setting before an HAI outbreak occurs is to exploit native fluorescence of cellula...

Rationale Novel therapeutic strategies are required to protect the heart against ischaemia-reperfusion injury. Assessment of the efficacy of cardioprotective strategies requires measurement of both myocardial infarct size (IS) and the area of ‘at-risk’ myocardium (AAR). Recent studies suggest that T2-weighted cardiac magnetic resonance imaging (cMR...

Subjects were shown photographs of UK MPs' faces and asked to judge their political affiliations. Participants were unable to correctly distinguish between Conservative and Labour politicians. However, their responses were used to create computer-generated idealised faces representative of each party, which independent evaluators could correctly id...