No abstract

US of knees is more sensitive than radiography for CPPD diagnosis.

Background Calcium pyrophosphate disease (CPPD) is a common disease characterized by deposition of calcium pyrophosphate (CPP) crystals in joints and tendons. The diagnosis is made by identification of CPP crystal in synovial fluid analysis or by imaging such as X-rays or ultrasound (US). However, the performance of the two imaging procedures in the diagnosis of CPPD was poorly studied. Objectives The aim of the study was to investigate the reproducibility of US and its ability to detect CPP deposition in comparison to conventional X-rays. Methods To be included in this single-centre case-control study, patients needed to have painful knee effusion. The final diagnosis of CPPD was proven by identification of CPP crystals in synovial fluid analysis. All patients underwent a clinical evaluation, X-rays of knees in both anteroposterior and lateral views and US evaluation. All US exams were bilaterally performed by 2 rheumatologists blinded to clinical, laboratory, US and radiographic results. Knees cartilage was explored on the transversal and longitudinal suprapatellar plane in maximal flexion. Lateral and medial menisci of the knees were assessed in moderate flexion (30°) and complete extension. Presence of hyperechoic spots in cartilage and menisci were assessed for both knees. Interobserver agreement between the 2 sonographers was estimated using the k coefficient. Results A total of 32 patients (56% of males, mean age: 66.5±15.6 years) with knee effusion were included. Synovial fluid analysis revealed CPP crystals in 16 (50%) patients. Control patients were diagnosed gout (n=6), osteoarthritis (n=6), rheumatoid arthritis (n=2) and spondyloarthritis (n=2). Among the 16 patients with CPP crystals, US revealed hyperechoic spots in menisci and/or cartilage in all patients (Se: 100%, Sp=87.5%) whereas X-rays showed CPPD in 9 patients (Se: 56%, Sp: 100%) (P=0.002). Accuracy of US and X-rays was 93.8% and 78.1%, respectively. Calcifications of menisci were detected by US in 15 (93.7%) of the 16 CPPD patients and in 2 (13.5%) of 16 control patients. Hyperechoic spots of cartilage were noted among CPPD and control group, in 12 (75%) and 1 (6.2%) patients, respectively. Agreement between the 2 sonographers was almost perfect for US CPPD (menisci and/or cartilage calcifications) diagnosis (k=0.87), menisci (k=0.81) and cartilage calcification (k=0.81). Conclusions Our study confirms that US of knees is more sensitive than X-rays for the diagnosis of CPPD despite lower specificity. Additionally, the reproducibility of US was good. Thus, US appears to be useful for the diagnosis of CPPD. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.3849

No abstract

Background Recently, ultrasonography (US) demonstratted its ability to detect urate deposition in gouty patients. Some US features have been suggested to be specific such as tophus and the double contour sign. In contrast to the usefulness of US for diagnosis, data are lacking on its place in follow-up of gout deposition after initiation of urate-lowering therapy (ULT). Objectives We aimed to determine the ability of US to show disappearance of urate deposits in gouty patients requiring ULT. Methods To be included in this prospective single-centre study, patients needed to exhibit 1) proven gout by crystals in synovial fluid and 2) US-evidenced urate deposits (double contour [DC] sign and/or tophi) before starting ULT. At baseline and after 6 months of ULT, one trained ultrasonographer assessed the knee and first metatarsophalangeal (MTP1s) joints. Serum uric-acid (SUA) level was assessed at baseline and at 3 and 6 months after ULT initiation. Correlation between US findings and achievement of SUA level objective (<360 μmol/l) was estimated by the kappa coefficient (k). Results We studied 16 patients (all males, mean age 61.0±18.3 years). The mean disease duration was 7.1±6.2 years. Tophi were found at clinical exam in 56% of patients. Baseline SUA levels were 688±153 μmol/l. At baseline, US revealed tophi or a DC sign among 62.5% to 75% of patients in knees and 87.5% in MTP1s. Among 3 of the 4 patients not achieving the SUA level objective, US features had not disappeared. Among the remaining 12 patients, US features disappeared or decreased in all but one with a stable DC sign in one MTP1. The correlation between the whole US examination and SUA level was excellent (k=0.875). Conclusions Our results suggest that screening for specific features of gout such as tophi or DC sign by US at the initiation of ULT and during follow-up is a sensitive way to detect the disappearance of urate deposits in gout. Moreover, correlation was good between modification of US-observed features of gout and SUA levels decreased to below the recommended SUA objective. Although these findings are promising, future randomized studies with a large number of patients are required to definitely validate US assessment for gout treated with ULT. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.2941