Ultrasound and magnetic resonance imaging assessment of joint disease in symptomatic patients with cystic fibrosis arthropathy.

OBJECTIVES: Cystic fibrosis arthropathy (CFA) is a term commonly used for joint pain with and without swelling seen in some patients with CF. Early studies into CFA focused on the presence of rheumatoid factor and immunological changes on synovial biopsy, with parallels drawn between respiratory and joint activity. Identification of anti-cyclic citrullinated peptide antibodies (anti-CCP) as a marker of rheumatoid arthritis (RA), along with increased access to sensitive imaging techniques including ultrasound (US) and magnetic resonance imaging (MRI), offer great potential to investigate and more accurately understand the type(s) of inflammatory arthritis that may underlie CFA. The aim of this study was to phenotype an active CFA cohort using serology and imaging, as a basis for further work in this understudied area. METHODS: This was a prospective observational cohort study of symptomatic CFA patients presenting with joint pain. Participants underwent serological testing, clinical and US joint and entheseal assessment, as well as MRI of the most symptomatic joint/joint area. RESULTS: Ten symptomatic patients were studied with 9/10 having positive clinical findings. Inflammatory changes on US were seen in 8/10 cases. Five patients had positive findings on MRI (3 of whom had received IV gadolinium contrast). This included patients with significant erosive changes. One patient was anti-CCP positive suggestive of RA, and two were anti-nuclear antibody positive. CONCLUSION: Imaging, and to a lesser extent serology, identified inflammatory joint pathology in a proportion of cases, providing important data to explore in a large CFA cohort examining the clinical and imaging phenotype of this group.

A diagnostic algorithm for persistence of very early inflammatory arthritis: the utility of power Doppler ultrasound when added to conventional assessment tools.

OBJECTIVES: The aim of this study was to assess the value of power Doppler ultrasound (PDUS) in combination with routine management in a cohort of patients with very early inflammatory arthritis (IA). METHODS: 50 patients with < or =12 weeks of inflammatory symptoms with or without signs had clinical, laboratory and imaging assessments. Diagnosis was recorded at 12 months. Assuming a 15% pre-test probability of IA, post-test probabilities for various assessments were calculated and used to develop a diagnostic algorithm. RESULTS: All patients positive for rheumatoid factor (RF) and/or cyclic citrullinated peptide (CCP) developed persistent IA, so the added value of PDUS was assessed in the seronegative (RF and CCP negative) group. The probability of IA in a seronegative patient was 6%. The addition of clinical and radiographic features raised the probability of IA to 30% and, with certain ultrasound features, this rose to 94%. CONCLUSIONS: In seronegative patients with early IA, combining PDUS with routine assessment can have a major impact on the certainty of diagnosis.

The optimal assessment of the rheumatoid arthritis hindfoot: a comparative study of clinical examination, ultrasound and high field MRI.

OBJECTIVES: The aim of this pilot study was to compare clinical examination (CE) and ultrasound (US) with high field MRI (as the reference standard) for the detection of rearfoot and midtarsal joint synovitis and secondly tenosynovitis of the ankle tendons in patients with established rheumatoid arthritis (RA). METHODS: Patients with RA (as determined by the modified American College of Rheumatology (ACR) criteria) with symptoms of midfoot and rearfoot disease were recruited. Demographic data were collected. All underwent CE, US and high field MRI (with intravenous gadolinium contrast) of their right foot. Percentage exact agreement (PEA), sensitivity and specificity were calculated for CE and US when compared to MRI. Inter-reader reliability for CE and US was also assessed. RESULTS: Compared to the gold standard of MRI, for CE (joint synovitis) the ranges for sensitivity, specificity and PEA were 55-83%, 23-46% and 46-60%, and for US were 64-89%, 60-80% and 64-78%, respectively. Compared to the gold standard of MRI, for CE (tenosynovitis) the ranges for sensitivity, specificity and PEA were 0-100%, 20-91% and 55-91%, and for US were 0-67%, 86-100% and 59-86%, respectively. CONCLUSION: CE was sensitive but US more specific in identifying hindfoot pathology in RA when compared to the reference standard of MRI. There was poor interobserver variability between ultrasonographers suggesting a need for standardisation of acquisition and interpretation of US images of the hindfoot.