Objective: To investigate by high frequency ultrasonography the appearance of calcium pyrophosphate dihydrate (CPPD) calcifications, in the most commonly affected sites in CPPD disease, and the relationship between ultrasonographic CPPD deposits and the presence of CPPD crystals in synovial fluid. Methods: Three ultrasonographic patterns of CPPD calcification were identified and 11 patients enrolled. A control group comprised 13 patients with no evidence of CPPD deposits. Synovial fluid was aspirated from all patients and controls and examined for identification of crystals. All patients underwent a standard radiography examination at the same sites investigated by ultrasound. Results: In all patients with ultrasonographically defined CPPD deposits, CPPD crystals were found in the synovial fluid. In two cases, standard radiographic examination did not show evidence of the calcific deposits that were identified by ultrasonography. CPPD crystals were not found in the synovial fluid of controls. In four control group patients, ultrasonography identified calcifications defined as deposits of another nature. Conclusions: The ultrasonographic pattern used in this study for the diagnosis of CPPD disease demonstrated a very high correlation with the presence of CPPD crystals in synovial fluid. Ultrasonography demonstrated a sensitivity and specificity at least equal to that of radiography in identifying CPPD crystal calcifications.

Objective: To establish by ultrasonography (US) the frequency of calcaneal entheses involvement in erosive osteoarthritis (EOA), nodal osteoarthritis (NOA), RA and PsA, and to compare these results in order to aid clinicians in the differential diagnosis among these diseases. A comparison between US results and radiography was also made. Methods: The heels of 56 consecutive outpatients with EOA, 209 with NOA, 158 with RA and 125 with PsA were studied by US and radiography. A control group of 50 subjects was examined by US. Results: US showed no significant difference in inferior calcaneal enthesophytosis among the four diseases. The frequency of posteroinferior enthesophytosis was lower in RA (34%) in comparison with the other diseases (57% in EOA, 47% in NOA, 49% in PsA). Achilles enthesitis was found in 8% of PsA and in 2% of RA. Retrocalcaneal bursitis was found in 18% of RA and in 6% of PsA. Posterior erosions were present in 12% of RA and 5% of PsA. Inferior erosions were present in 6% of RA and in 1% of PsA. Plantar fasciitis was found in 26% of RA, in 37% of PsA, and in 15% of NOA and 12% of EOA. Subcalcaneal panniculitis was observed in 10% of RA and in 1% of PsA. In the control group, only posteroinferior and inferior enthesophytosis (22% and 18% respectively) were found. Kappa statistics show excellent agreement between US and radiography in detecting posteroinferior (κ=0.89) and inferior enthesophytosis (κ=0.83), and entheseal erosions (κ=0.86). Conclusions: The calcaneal lesions that could be found in EOA are similar to those observed in NOA. The frequency of calcaneal enthesophytosis is similar in EOA, NOA, and PsA, but inflammatory lesions of calcaneal entheses and of the adjacent bursae are more frequent in RA and in PsA. In terms of heel involvement, EOA seems to be similar to NOA. US shows an excellent concordance with radiography in detecting entheseal cortical bone abnormalities.

Joint ultrasonography is an innocuous diagnostic technique that is well tolerated by patients, and is the elected method for observing calcified deposits in soft tissues.²

Objective: The main objective of this study was to analyse the prevalence and characteristics of subclinical GCA in patients with PMR. Methods: This was a cross-sectional multicentre international study of consecutive patients with newly diagnosed PMR without symptoms or signs suggestive of GCA. All patients underwent US of the temporal superficial, common carotid, subclavian and axillary arteries. Patients with halo signs in at least one examined artery were considered to have subclinical GCA. The clinical, demographic and laboratory characteristics of the PMR group without subclinical vasculitis were compared with subclinical GCA, and the pattern of vessel involvement was compared with that of a classical single-centre GCA cohort. Results: We included 346 PMR patients, 267 (77.2%) without subclinical GCA and 79 (22.8%) with subclinical GCA. The PMR patients with subclinical GCA were significantly older, had a longer duration of morning stiffness and more frequently reported hip pain than PMR without subclinical GCA. PMR with subclinical GCA showed a predominant extracranial large vessel pattern of vasculitic involvement compared with classical GCA, where the cranial phenotype predominated. The patients with PMR in the classical GCA group showed a pattern of vessel involvement similar to classical GCA without PMR but different from PMR with subclinical involvement. Conclusion: More than a fifth of the pure PMR patients had US findings consistent with subclinical GCA. This specific subset of patients showed a predilection for extracranial artery involvement. The optimal screening strategy to assess the presence of vasculitis in PMR remains to be determined.