Minimizing Stimulus Current in a Wearable Pudendal Nerve Stimulator Using Computational Models.

After spinal cord injury, functions of the lower urinary tract may be disrupted. A wearable device with surface electrodes which can effectively control the bladder functions would be highly beneficial to the patients. A trans-rectal pudendal nerve stimulator may provide such a solution. However, the major limiting factor in such a stimulator is the high level of current it requires to recruit the nerve fibers. Also, the variability of the trajectory of the nerve in different individuals should be considered. Using computational models and an approximate trajectory of the nerve derived from an MRI study, it is demonstrated in this paper that it may be possible to considerably reduce the required current levels for trans-rectal stimulation of the pudendal nerve compared to the values previously reported in the literature. This was corroborated by considering an ensemble of possible and probable variations of the trajectory. The outcome of this study suggests that trans-rectal stimulation of the pudendal nerve is a plausible long term solution for treating lower urinary tract dysfunctions after spinal cord injury

Emerging quantitative MR imaging biomarkers in inflammatory arthritides

PURPOSE: To review quantitative magnetic resonance imaging (qMRI) methods for imaging inflammation in connective tissues and the skeleton in inflammatory arthritis. This review is designed for a broad audience including radiologists, imaging technologists, rheumatologists and other healthcare professionals. METHODS: We discuss the use of qMRI for imaging skeletal inflammation from both technical and clinical perspectives. We consider how qMRI can be targeted to specific aspects of the pathological process in synovium, cartilage, bone, tendons and entheses. Evidence for the various techniques from studies of both adults and children with inflammatory arthritis is reviewed and critically appraised. RESULTS: qMRI has the potential to objectively identify, characterize and quantify inflammation of the connective tissues and skeleton in both adult and pediatric patients. Measurements of tissue properties derived using qMRI methods can serve as imaging biomarkers, which are potentially more reproducible and informative than conventional MRI methods. Several qMRI methods are nearing transition into clinical practice and may inform diagnosis and treatment decisions, with the potential to improve patient outcomes. CONCLUSIONS: qMRI enables specific assessment of inflammation in synovium, cartilage, bone, tendons and entheses, and can facilitate a more consistent, personalized approach to diagnosis, characterisation and monitoring of disease

The role of whole-body MRI in musculoskeletal inflammation detection and treatment response evaluation in inflammatory arthritis across age: A systematic review

OBJECTIVE: To evaluate the relation between whole-body MRI (WBMRI) outcomes and disease activity measures, including clinical examination, composite scores, and other imaging outcomes, and the ability of WBMRI to detect treatment response in patients with inflammatory arthritis (IA) across age. METHODS: Human studies published as full text or abstract in the PubMed and MEDLINE and Cochrane databases from inception to 11th April 2021 were systematically and independently searched by two reviewers. Studies including patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), spondyloarthritis (SpA), juvenile idiopathic arthritis (JIA) or unclassified inflammatory arthritis (UA) who underwent WBMRI and which reported on disease outcomes were included. RESULTS: Nineteen full-text studies were eligible for inclusion: 2 interventional, 7 retrospective and 10 prospective observational studies, comprising 540 participants (SpA 38.7%, RA 24.8%, JIA 17.8%, PsA 11.5%, healthy controls 5.9%, UA 1.3%). Abstracts of 6 conference papers were reported separately. Five studies in PsA and SpA and 4 in RA measured the frequency of WBMRI-detected and clinically-detected synovitis, and all found the former to be more frequent. Less enthesitis was detected by WBMRI than clinical examination in 5/8 studies. After biologic treatment, the WBMRI inflammation scores declined in 3 studies in SpA and 2 in RA, whilst in 3 studies the results were equivocal. CONCLUSION: The ability of WBMRI to assess disease activity and treatment response in IA was adequate overall. Further studies are needed to corroborate WBMRI findings with IA outcomes and investigate the clinical value of subclinical inflammation

Biomarkers of response to biologic therapy in juvenile idiopathic arthritis

Background: Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory arthritis of childhood, characterised by various clinical phenotypes associated with variable prognosis. Significant progress has been achieved with the use of biologic treatments, which specifically block pro-inflammatory molecules involved in the disease pathogenesis. The most commonly used biologics in JIA are monoclonal antibodies and recombinant proteins targeting interleukins 1 and 6, and tumour necrosis factor α (TNF-α). Several biomarkers have been investigated in JIA. Aims: To assess the level of evidence available regarding the role of biomarkers in JIA related to guiding clinical and therapeutic decisions, providing disease prognostic information, facilitating disease activity monitoring and assessing biologic treatment response in JIA, as well as propose new strategies for biologic therapy-related biomarker use in JIA. Methods: We searched PubMed for relevant literature using predefined key words corresponding to several categories of biomarkers to assess their role in predicting and assessing biologic treatment response and clinical remission in JIA. Results: We reviewed serological, cellular, genetic, transcriptomic and imaging biomarkers, to identify candidates that are both well-established and widely used, as well as newly investigated in JIA on biologic therapy. We evaluated their role in management of JIA as well as identified the unmet needs for new biomarker discovery and better clinical applications. Conclusions: Although there are no ideal biomarkers in JIA, we identified serological biomarkers with potential clinical utility. We propose strategies of combining biomarkers of response to biologics in JIA, as well as routine implementation of clinically acceptable imaging biomarkers for improved disease assessment performance