Can power Doppler ultrasound of the entheses help in classifying recent axial spondyloarthritis? Data from the DESIR cohort

Abstract

Early diagnosis of axial spondyloarthritis (axSpA) remains a challenge due to the lack of specificity of clinical symptoms and variable prevalence of axial imaging findings permitting a definite diagnosis. Power Doppler ultrasonography (PDUS) of the entheses has demonstrated to be a potential useful tool for the classification and diagnostic management of early SpA independently of the phenotype.ObjectivesTo assess the classification value (sensitivity and specificity) of PDUS-defined enthesitis for identifying patients fulfilling Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axSpA (ASAS+) in patients with recent inflammatory back pain (IBP) (the DESIR (DEvenir des Spondylarthropathies Indifférenciées Récentes) cohort).MethodsBaseline PDUS was performed at eight entheseal sites, and PDUS enthesitis was defined by the presence of vascularisation at entheseal insertion.Results402 patients from the DESIR cohort underwent a PDUS evaluation. PDUS enthesitis was detected in 58 (14.4%) patients of whom 40 (14.2%) belonged to the ASAS+ patients and 18 (17%) to the ASAS- patients. The sensitivity of PDUS enthesitis was 13.9% and the specificity was 83.5%, with a positive predictive value of 69% and 26.8% of negative predictive value for meeting ASAS criteria for axSpA. Of the 18 ASAS- patients with positive PDUS, 59% fulfilled Amor’s criteria, 88% European Spondyloarthropathy Study Group criteria and 59% both.ConclusionsIn a cohort of patients with recent IBP, the prevalence of PDUS enthesitis was low (14.4%); however, its specificity for classifying patients as axSpA according to ASAS criteria was high (83.5%). PDUS enthesitis might be of additional value for classifying as patients with axSpA IBP who do not fulfil ASAS criteria.

A Systematic Review of the Inclusion of Non-Inflammatory Ultrasonographic Enthesopathy Findings in Enthesitis Scoring Indices

“…Color PD is an important feature in evaluating enthesopathies with US. Color PD detects neovascularization of the insertion of the enthesis into the cortical bone, a feature of enthesitis [ 32 , 44 , 45 ]. In 2018, the OMERACT US initiative published consensus-based definitions regarding power Doppler in spondylarthritis.…”

A Narrative Review of the Classification and Use of Diagnostic Ultrasound for Conditions of the Achilles Tendon

“…Several studies have found the presence of blood vessels in the enthesis to be specific for spondyloarthropathies [ 3 , 4 , 11 , 98 , 99 ]. D’Agostino et al evaluated entheses of 164 patients with a spondyloarthropathy, 34 with mechanical back pain (MBP) and 30 with rheumatoid arthritis (RA); vascularization at the enthesis was found in 81% of spondyloarthropathy patients but in none of the patients with MBP or RA [ 100 ]. While this is not histologic confirmation of inflammation, neovascularization within this region may be the closest finding on US to confirming inflammatory changes.…”

“…An increasing number of studies have further demonstrated the presence of blood vessels at the tendon insertion in the cortical bone in spondyloarthropathy patients [ 100 , 102 , 103 , 104 ]. However, there is no clear consensus on which substructures in these studies demonstrated Doppler signal (e.g., tendon, bursa).…”

“…D’Agostino et al developed a criteria for evaluating what the authors termed enthesitis. The scoring system included points for tendon thickness, hypoechogenicity, calcification, erosion, and vascularization [ 100 ]. More specific to enthesitis, the authors semiquantified vascularization with Doppler signal on a scale of 0–3.…”

“…More specific to enthesitis, the authors semiquantified vascularization with Doppler signal on a scale of 0–3. The vascularization was scored as 0 if Doppler signal was absent, 1 if Doppler signal was minimal (one color spot detected), 2 if Doppler signal was moderate (two spots), or 3 if Doppler signal was severe (≥three spots) [ 100 ].…”