Ultrasound in the evaluation of enthesitis: status and perspectives

Abstract

IntroductionAn increasing number of studies have applied ultrasound to the evaluation of entheses in spondyloarthritis patients. However, no clear agreement exists on the definition of enthesitis, on the number and choice of entheses to examine and on ultrasound technique, which may all affect the results of the examination. The objectives of this study were to first determine the level of homogeneity in the ultrasound definitions for the principal lesions of enthesitis in the published literature and second, to evaluate the metric properties of ultrasound for detecting enthesitis according to the OMERACT filter.MethodsSearch was performed in PUBMED and EMBASE. Both grey-scale and Doppler definitions of enthesitis, including describing features of enthesitis, were collected and metrological qualities of studies were assessed.ResultsAfter selection, 48 articles were analyzed. The definition of ultrasound enthesitis and elementary features varied among authors. Grey-scale enthesitis was characterized by increasing thickness (94% of studies), hypoechogenicity (83%), enthesophytes (69%), erosions (67%), calcifications (52%), associated bursitis (46%) and cortical irregularities (29%). Only 46% of studies reported the use of Doppler. High discrepancies were observed on frequency, type of probe and Doppler mode used. Face and content validity were the most frequently evaluated criteria (43%) followed by reliability (29%) and responsiveness (19%).ConclusionsUltrasound has evidence to support face, content validity and reliability for the evaluation of enthesitis, though there is a lack of well-reported methodology in most of the studies. Consensus on elementary lesions and standardization of exam is needed to determine the ultrasound definition of enthesitis in grey-scale and in Doppler for future applications.

Defining Enthesitis in Spondyloarthritis by Ultrasound: Results of a Delphi Process and of a Reliability Reading Exercise

“…A recent systematic literature review highlighted a great variability in the definition of enthesitis in SpA applied in US studies since the first publication in 1985 (12) and, in particular, definitions of its constituent elementary components. The literature review underlined the necessity for a more refined definition of enthesitis and its components.…”

“…The construction of the questionnaire was made using data collected from a recent systematic literature review (12), data from preceding studies performed by some members of the group (3,4,13), and information obtained from a preliminary meeting of the members of the Task Force listing the areas of interest. This collated information resulted in 14 statements grouped under the 4 following subheadings: 1) definition of a normal US enthesis and other related anatomic structures, 2) elementary lesions to be included in both B-mode and Doppler assessment of enthesitis, 3) US definition of individual elementary lesions, and 4) lesions reflecting inflammation and damage.…”

“…As a result, this led to a number of studies proposing different US scoring systems (3,4,10,11). This lack of consensus was highlighted in a recent systematic literature review (12) that showed nonuniformity both in the definitions being applied and on the technical parameters and scanning methods used. In order to improve the use of US in the evaluation of SpA-related enthesitis, an OMERACT Task Force subgroup was formed.…”

Imaging in ankylosing spondylitis

“…The reader is referred to other reviews (e.g. Gandjbakhch et al [2011] and Poggenborg et al [2011]) for further information on this.…”

Updating the OMERACT Filter: Implications for Imaging and Soluble Biomarkers

“…], for example, MMP3 is significantly associated with this endpoint and it is now under further evaluation 54,55,56,57,58 . Among imaging techniques, ultrasound was considered an interesting candidate for assessing SpA enthesitis as a marker of inflammatory activity both at site specific (entheses) and patient levels 59,60,61,62,63 .…”