Detecting joint inflammation by an LED-based photoacoustic imaging system: a feasibility study (Erratum).

An error in the first author's name is corrected.

Detecting joint inflammation by an LED-based photoacoustic imaging system: a feasibility study.

Light-emitting diode (LED) light sources have recently been introduced to photoacoustic imaging (PAI). The LEDs enable a smaller footprint for PAI systems when compared to laser sources, thereby improving system portability and allowing for improved access. An LED-based PAI system has been employed to identify inflammatory arthritis in human hand joints. B-mode ultrasound (US), Doppler, and PAIs were obtained from 12 joints with clinically active arthritis, five joints with subclinically active arthritis, and 12 normal joints. The quantitative assessment of hyperemia in joints by PAI demonstrated statistically significant differences among the three conditions. The imaging results from the subclinically active arthritis joints also suggested that the LED-based PAI has a higher sensitivity to angiogenic microvascularity compared to US Doppler imaging. This initial clinical study on arthritis patients validates that PAI can be a potential imaging modality for the diagnosis of inflammatory arthritis.

Photoacoustic tomography for human musculoskeletal imaging and inflammatory arthritis detection.

With the capability of assessing high resolution optical contrast in soft tissues, photoacoustic imaging (PAI) can offer valuable structural and functional information of human joints, and hold potential for diagnosis and treatment monitoring of inflammatory arthritis. Recent studies have demonstrated that PAI can map 2D and 3D morphology of the cartilage, synovium, vascularity, and bone tissue in human peripheral joints. Initial trials with patients affected by inflammatory arthritis have also suggested that PAI can detect the hemodynamic properties in articular tissues as well as their changes due to active inflammation. This review focuses on the recent progress in technical development of PAI for human musculoskeletal imaging and inflammation detection. PAI can provide non-invasive and non-ionizing serial measurements for monitoring of therapeutic interventions with the potential for higher sensitivity than existing imaging modalities such as ultrasound. However, further investigation is needed to validate the value of PAI in rheumatology clinical settings.

Case series: Monoarticular rheumatoid arthritis.

OBJECTIVE: Monoarticular presentation of rheumatoid arthritis is infrequent and has been previously reported to involve large joints such as the hip and knee joints. Here we report a case series of four patients presenting to the University of Michigan in 2015 with monoarticular rheumatoid arthritis, one with small and three with large joint involvement. MATERIAL AND METHODS: In total, four patients with monoarticular rheumatoid arthritis were treated in the Division of Rheumatology, University of Michigan. All the patients were retrospectively reviewed with permission from our Institutional Review Board; informed consent was provided by the patients for enrollment in a clinical trial for patients with rheumatoid arthritis. All the patients were assessed using the 2010 ACR/EULAR classification criteria for rheumatoid arthritis. RESULTS: All the patients presented with monoarthritis; three patients had large joint involvement and one had small joint involvement. Serologies were positive, with each patient having positive Anti-cyclic citrullinated peptide (anti-CCP) antibodies, two patients having a positive rheumatoid factor, three patients having elevated CRP levels, and one patient having positive ESR. All patients met the criteria of the duration of symptoms being at least 6 weeks. The findings of imaging, although not a part of the criteria, were consistent with active rheumatoid arthritis in all the patients. CONCLUSION: While the 2010 ACR/EULAR classification criteria are the most sensitive criteria for diagnosing RA to date, the exclusion of these cases of monoarthritis demonstrates that further specificity can still be achieved for diagnosing these types of patients as early as possible using the current guidelines. Further, we suggest the inclusion of an imaging measure added to the inclusion criteria to further increase the yield in establishing diagnosis of rheumatoid arthritis in the current reported patient population.

The sphingosine-1-phosphate receptor: A novel therapeutic target for multiple sclerosis and other autoimmune diseases.

Multiple sclerosis (MS) is a prototype autoimmune disease of the central nervous system (CNS). Currently, there is no drug that provides a cure for MS. To date, all immunotherapeutic drugs target relapsing remitting MS (RR-MS); it remains a daunting medical challenge in MS to develop therapy for secondary progressive MS (SP-MS). Since the approval of the non-selective sphingosine-1-phosphate (S1P) receptor modulator FTY720 (fingolimod [Gilenya®]) for RR-MS in 2010, there have been many emerging studies with various selective S1P receptor modulators in other autoimmune conditions. In this article, we will review how S1P receptor may be a promising therapeutic target for SP-MS and other autoimmune diseases such as psoriasis, polymyositis and lupus.