From Macro to Nano: Linking Quantitative CEUS Perfusion Parameters to CD4~+ T Cells Subtypes in Spondyloarthtitis

摘要

The onset and progression of immune-mediated inflammatory arthritis, such as rheumatoid arthritis and spondyloarthritis, are linked to the IL23-IL17 immune axis, so that many therapeutic strategies aim at modulating this pathway. However, there is so far no possibility of an in vivo direct monitoring, without a biopsy, of the specific T cells involved in this modulation. Synovial perfusion, and thus synovial angiogenesis, has been recognized as a sensitive and early marker of inflammation that can be evaluated via quantitative analysis of contrast-enhanced ultrasound imaging data. We propose a quantitative analysis of contrast enhanced ultrasound data, exploiting both a pixel-wise analysis for characterizing the perfusion patterns and their heterogeneity within a patient's synovia, and a model that add to the gamma-variate function a term accounting for a possible slow-flow component, whose presence and amplitude is estimated via a variational Bayesian method. We show that this quantification allows to find a relationship between perfusion parameters to CD4~+ T helper cells subtypes that are believed to be involved in the IL23-IL17 immune axis modulation: significant correlations are as high as 0.90, suggesting the possibility of estimating T cells concentration from non-invasive imaging data.