Combined MR direct thrombus imaging and non-contrast magnetic resonance venography reveal the evolution of deep vein thrombosis: a feasibility study.

OBJECTIVES: Lower limb deep venous thrombosis (DVT) is a common condition with high morbidity and mortality. The aim of the study was to investigate the temporal evolution of the acute thrombus by magnetic resonance imaging (MRI) and its relationship to venous recanalization in patients with recurrent DVTs. METHODS: Thirteen patients with newly diagnosed lower limb DVTs underwent MRI with non-contrast MR venography (NC-MRV) and MR direct thrombus imaging (MR-DTI), an inversion-recovery water-selective fast gradient-echo acquisition. Imaging was performed within 7 days of the acute thrombotic event, then at 3 and 6 months. RESULTS: By 3 months from the thrombotic event a third of the thrombi had resolved and by 6 months about half of the cases had resolved on the basis of vein recanalisation using NC-MRV. On the initial MR-DTI acute thrombus was clearly depicted by hyperintense signal, while the remaining thrombi were predominantly low signal at 3 and 6 months. Some residual thrombi contained small and fragmented persisting hyperintense areas at 3 months, clearing almost completely by 6 months. CONCLUSIONS: Our study suggests that synergistic venous assessment with combined NC-MRV and MR-DTI is able to distinguish acute venous thrombosis from the established (old) or evolving DVT detected by ultrasound. KEY POINTS: • MRI can distinguish between acute and evolving or chronic lower limb DVT • Two advanced MRI techniques can follow the evolution of lower limb DVT • MRI could be used to avoid an incorrect diagnosis of recurrent DVT • MRI could help avoid the risks and complications of lifelong anticoagulation therapy.National Institute for Health Research, Addenbrooke’s Charitable TrustThis is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00330-016-4555-

Comparison of breath-hold, respiratory navigated and free-breathing MR elastography of the liver

$\textit{Purpose:}$ Hepatic magnetic resonance elastography (MRE) is currently a breath-hold imaging technique. Patients with chronic liver disease can have comorbidities that limit their ability to breath-hold (BH) for the required acquisition time. Our aim was to evaluate whether stiffness measurements obtained from a navigator-triggered MRE acquisition are comparable to standard expiratory breath-hold, inspiratory breath-hold or free-breathing in healthy participants. $\textit{Materials and methods:}$ Twelve healthy participants were imaged using the four methods on a clinical 1.5 T MR system equipped with a product MRE system. Mean liver stiffness, and measurable area of stiffness (with a confidence threshold >95%) were compared between sequences using the concordance correlation coefficient. Repeatability of each sequence between two acquisitions was also assessed. $\textit{Results:}$ The standard BH expiratory technique had high concordance with the navigated technique (r = 0.716), and low concordance with the BH inspiration (r = 0.165) and free-breathing (r = 0.105) techniques. The navigator-triggered technique showed no statistical difference in measurable area of liver or in repeatability compared with the standard expiratory acquisition (p = 0.997 and p = 0.407 respectively). The free-breathing technique produced less measurable liver area and was less repeatable than the alternative techniques. The increase in acquisition time for navigator techniques was 3 min 6 s compared to standard expiratory breath-hold. $\textit{Conclusion:}$ Navigator-based hepatic MRE measurements are comparable to the reference standard expiratory breath-hold acquisition in healthy participants.This work was supported by the Addenbrooke's Charitable Trust and the NIHR Comprehensive Biomedical Research Centre award to Cambridge University Hospitals NHS Foundation Trust in partnership with the University of Cambridge

Amniotic fluid volume: Rapid MR-based assessment at 28-32 weeks gestation.

OBJECTIVES: This work evaluates rapid magnetic resonance projection hydrography (PH) based amniotic fluid volume (AFV) estimates against established routine ultrasound single deepest vertical pocket (SDVP) and amniotic fluid index (AFI) measurements, in utero at 28-32 weeks gestation. Manual multi-section planimetry (MSP) based measurement of AFV is used as a proxy reference standard. METHODS: Thirty-five women with a healthy singleton pregnancy (20-41 years) attending routine antenatal ultrasound were recruited. SDVP and AFI were measured using ultrasound, with same day MRI assessing AFV with PH and MSP. The relationships between the respective techniques were assessed using linear regression analysis and Bland-Altman method comparison statistics. RESULTS: When comparing estimated AFV, a highly significant relationship was observed between PH and the reference standard MSP (R(2) = 0.802, p < 0.001). For the US measurements, SDVP measurement related most closely to amniotic fluid volume, (R(2) = 0.470, p < 0.001), with AFI demonstrating a weaker relationship (R(2) = 0.208, p = 0.007). CONCLUSION: This study shows that rapid MRI based PH measurement is a better predictor of AFV, relating more closely to our proxy standard than established US techniques. Although larger validation studies across a range of gestational ages are required this approach could form part of MR fetal assessment, particularly where poly- or oligohydramnios is suspected. KEY POINTS: • MR projection hydrography can be used to estimate amniotic fluid volume. • MR projection hydrography relies on the T2w signal from amniotic fluid. • Amniotic fluid volume (AFV) is more accurately assessed than with ultrasound.This study was supported by the National Institute of Health Research, Cambridge Biomedical Research Centre. The authors also acknowledge the support of Addenbrooke’s Charitable Trust and thank the participants for their contribution to the study.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00330-015-4179-

Children’s perceptions of factors that influence PE enjoyment: A qualitative investigation

Background. Physical education (PE) is a key setting for children to engage in health-enhancing physical activity (PA). Factors influencing PE enjoyment in secondary schools are well researched. Less is known, however, about the factors children in elementary schools perceive to be important in promoting enjoyment, and how the current PE delivery framework in UK primary schools (combining specialist external coaches and generalist teachers) impacts on children’s motivational experiences. According to self-determination theory (SDT), enjoyment of activities is an intrinsic motivator for sustained engagement. Understanding children’s perceptions of PE is therefore critical if PE instructors are to increase enjoyment and the promotion of PA within and beyond PE. Purpose. To investigate children’s perceptions of factors that influence PE enjoyment, and interpret findings in the context of SDT and the promotion of autonomous motivation. Participants. Primary school pupils recruited from a cluster of four schools within a socio-economically deprived area of a large city in the North-West of England. Data collection and analysis. Eight focus groups were conducted with 47 children (23 boys) aged 7-11. Mixed gender focus groups included 4-6 children clustered by school years 3-4 (ages 7-9 years) and 5-6 (ages 9-11 years). Children were asked about their PE experiences and factors that influenced their perceived PE enjoyment. Transcripts were transcribed verbatim and analysed thematically using NVivo10 analysis software. Findings. Factors reported to influence children’s perceived PE enjoyment included 1) individual preferences, 2) peer behaviour, 3) instructor behaviour. Findings were interpreted in relation to SDT, and recommendations are given to help instructors and schools create a PE environment that enhances children’s enjoyment of PE. Conclusions. PE instructors and peers are important in creating an environment that supports children’s psychological needs for autonomy, competence and relatedness, which influence PE enjoyment. To consistently provide children with enjoyable PE lessons, primary schools are advised to support the ongoing development of generalist teachers and facilitate better working relationships between generalist teachers and specialist coaches. SDT can be used by instructors to guide practice that enhances children’s enjoyment of PE

Educator perspectives on factors influencing children’s school-based physical activity

Formative research is an important first step in the design and development of children’s school-based physical activity (PA) interventions. Exploration of educator (headteacher and PE-coordinator) perceptions toward the promotion of school-based PA, including physical education (PE) delivery has however been limited. This study took a socio-ecological approach to explore the barriers and facilitators of children’s school-based PA from the perspective of school educators. Interviews were conducted with headteachers (n=4), PE-coordinators (n=4) and a deputy headteacher (n=1) and data thematically analysed using Nvivo software (version 10). Findings suggested that, at an organisational level headteachers were the predominant driving force in the promotion of PA opportunities, yet institutional barriers including low priority for PA and PE were perceived to negate delivery. At an interpersonal level, strategies to increase the delivery of school-based PA were developed, however poor teacher-coach relationships and significant others reduced PA promotion opportunities. Child PA was further negated through intrapersonal factors, including lack of PE-specific teacher training and varying teacher interest in PA and sport. To increase primary school children’s school-based PA, barriers and facilitators at the organisational, interpersonal and intrapersonal level must be considered and targeted, and researchers and schools should work in partnership to develop future interventions

Feasibility of metabolic imaging of hyperpolarized 13C-pyruvate in human breast cancer

Introduction Imaging of the breast with hyperpolarized 13C yields new challenges compared to imaging the prostate [1]. E.g. large anteroposterior B0 gradients [2] require correction and the anatomy and patient positioning need a new, highly optimized RF coil array for achieving sufficient SNR/spatial resolution. As a first step, we have investigated single-breast imaging in the coronal plane. Methods A BRCA gene carrier with a 38-mm diameter grade 3 triple-negative invasive ductal carcinoma was studied on a 3T MRI (GE Healthcare) using a prototype 8-channel 13C breast coil (Rapid Biomedical), containing 2 transmit/receive coils and 6 receive-only covering both breasts in a prone position. 1H imaging was performed with the body coil. Following injection of 40ml of 250mM 13C-pyruvate, polarized to c. 25%, a 1-minute time series of spirals with IDEAL encoding (3) was collected (flip angle 10°, TR=260ms, 8-step cycle, time resolution 2.08s, 3 x 3-cm thick slices, 3mm gap, 40-pt spiral, 24cm coronal FOV, real pixel size 12 x 12 x 30mm). IDEAL reconstruction of images was optimized separately for each slice to enable independent frequency offsets to be applied. Kinetic modelling was performed in MATLAB, with automated tumour segmentation. Results Tumour pixels were identified by the segmentation algorithm only in the tumour-containing slice 2, and the average estimated flux from pyruvate to lactate kPL within this ROI was 0.022 s-1 (Fig. 1). The frequency shift of pyruvate relative to slice 2 was +6 Hz in slice 3 and -34 Hz in slice 1, confirming a sharp gradient in B0 approaching the nipple, which was corrected by optimizing slices separately (Fig 2). Images of lactate and pyruvate summed over the time course (Fig 3) showed strong signal of both metabolites over the tumour in slice 2, lower pyruvate in the slice toward the chest wall, and no consistent signal in slice 1. Conclusion This first-in-Europe study in breast cancer established the feasibility of obtaining metabolite images with high temporal and moderate spatial resolution in humans in vivo following administration of hyperpolarized 13C-pyruvate. Coronal image orientation allowed application of significant corrections for a known limitation, the anteroposterior B0 gradient, as well as a small FOV to improve spatial resolution. Kinetic rate constants within the tumour were found to be consistent with previous reports in human prostate cancer (1). References 1) Nelson SJ et al. Sci Transl Med 5, 198ra108 (2013). 2) Maril N, et al. Magn. Reson. Med. 2005; 54:1139-1145. 3) Wiesinger F, et al. Magn Reson Med 2012; 68:8-16

Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation

FUNDING AND DISCLOSURE The research was funded by Wellcome Trust (WT098012) to LKH; and National Institute of Health (DK056731) and the Marilyn H. Vincent Foundation to MGM. The University of Michigan Transgenic Core facility is partially supported by the NIH-funded University of Michigan Center for Gastrointestinal Research (DK034933). The remaining authors declare no conflict of interest. ACKNOWLEDGMENTS We thank Dr Celine Cansell, Ms Raffaella Chianese and the staff of the Medical Research Facility for technical assistance. We thank Dr Vladimir Orduña for the scientific advice and technical assistance.Peer reviewedPublisher PD

Clinical exercise provision in the UK: comparison of staff job titles, roles and qualifications across five specialised exercise services

Objectives: In the UK, the NHS long-term plan advocates exercise as a key component of clinical services, but there is no clearly defined workforce to deliver the plan. We aimed to provide an overview of current UK clinical exercise services, focusing on exercise staff job titles, roles, and qualifications across cardiovascular, respiratory, stroke, falls, and cancer services. Methods: Clinical exercise services were identified electronically between May 2020 and September 2020 using publicly available information from clinical commissioning groups (CCG), national health boards and published audit data. Data relating to staff job titles, roles, qualifications and exercise delivery were collected via electronic records and telephone/e-mail contact with service providers. Results: Data were obtained for 731 of 890 eligible clinical services (216 cardiac, 162 respiratory, 129 stroke, 117 falls, 107 cancer). Cardiac rehabilitation services provided both clinical (phase III) and community (phase IV) exercise interventions delivered by physiotherapists, exercise physiologists (exercise specific BSc/MSc) and exercise instructors (vocationally qualified with or without BSc/MSc). Respiratory, stroke and falls services provided a clinical exercise intervention only, mostly delivered by physiotherapists and occupational therapists. Cancer services provided a community exercise service only, delivered by vocationally qualified exercise instructors. Job titles of “exercise physiologists” (n=115) bore little alignment to their qualifications, with a large heterogeneity across services. Conclusion: In the UK, clinical exercise services job titles, roles and qualifications were inconsistent. Regulation of exercise job titles and roles is required to remove the current disparities in this area