Low-field MRI versus ultrasound: which is more sensitive in detecting inflammation and bone damage in MCP and MTP joints in mild or moderate rheumatoid arthritis?

OBJECTIVES: The aim of the present paper is to determine if the ultrasound of hands and feet is comparable to the MRI of the dominant hand to detect erosive disease and inflammation in mild or moderate rheumatoid arthritis (RA). METHODS: Twenty-six patients (14 females; mean age, 48 years) with active mild or moderate RA (mean DAS28, 3.9; mean disease duration, 19 months) were examined clinically, by ultrasound and by gadolinium-enhanced low-field MRI at baseline, after 6 and 12 months (78 examinations). Radiographs from hands and forefeet were taken at baseline and after 12 months. MRI was performed at the clinically most active (dominant) hand or forefoot evaluating the MCP 1-5 or MTP 1-5 joints. Ultrasound examination additionally included all other 2nd, 5th MCP and 5th MTP joints. RESULTS: MRI and ultrasound detected erosive disease in 67 and 56 of 78 examinations, respectively (p<0.01); radiography only in 8 of 52 examinations (p<0.001). MRI and ultrasound were equally sensitive to detect synovitis (in 64 and 66 examinations). Synovial power Doppler signals were present in 38 ultrasound examinations. Bone marrow oedema was present in 37 MRI examinations. Ultrasound was more sensitive than MRI to detect tenosynovitis (in 30 vs. 15 examinations; p=0.001). CONCLUSIONS: MRI of the dominant hand and bilateral ultrasound of MCP and MTP joints are superior to x-ray to detect erosive disease in mild and moderate RA. MRI is slightly, but significantly more sensitive than ultrasound for erosive disease, while ultrasound is more sensitive to detect tenosynovitis. Ultrasound and MRI are comparably sensitive to detect synovitis.

Acetylcholine receptor pathway mutations explain various fetal akinesia deformation sequence disorders.

Impaired fetal movement causes malformations, summarized as fetal akinesia deformation sequence (FADS), and is triggered by environmental and genetic factors. Acetylcholine receptor (AChR) components are suspects because mutations in the fetally expressed gamma subunit (CHRNG) of AChR were found in two FADS disorders, lethal multiple pterygium syndrome (LMPS) and Escobar syndrome. Other AChR subunits alpha1, beta1, and delta (CHRNA1, CHRNB1, CHRND) as well as receptor-associated protein of the synapse (RAPSN) previously revealed missense or compound nonsense-missense mutations in viable congenital myasthenic syndrome; lethality of homozygous null mutations was predicted but never shown. We provide the first report to our knowledge of homozygous nonsense mutations in CHRNA1 and CHRND and show that they were lethal, whereas novel recessive missense mutations in RAPSN caused a severe but not necessarily lethal phenotype. To elucidate disease-associated malformations such as frequent abortions, fetal edema, cystic hygroma, or cardiac defects, we studied Chrna1, Chrnb1, Chrnd, Chrng, and Rapsn in mouse embryos and found expression in skeletal muscles but also in early somite development. This indicates that early developmental defects might be due to somite expression in addition to solely muscle-specific effects. We conclude that complete or severe functional disruption of fetal AChR causes lethal multiple pterygium syndrome whereas milder alterations result in fetal hypokinesia with inborn contractures or a myasthenic syndrome later in life.