title: Is the frequent sonographic anechoic area distally in metacarpophalangeal joints a sign of arthritis?
abstract: In clinical practice, ultrasonography (US) often reveals, in the dorsal scan, a small anechoic area distally in both inflamed and clinically non-inflamed metacarpophalangeal joints. This "distal anechogenicity in the metacarpophalangeal joint" (DAEM) might thus be scored false positively as arthritis. We aimed to investigate whether the DAEM is a sign of arthritis. We evaluated the prevalence of DAEMs in 24 non-arthritic subjects. We then compared the dimensions of the DAEM in 10 non-arthritic subjects with a DAEM and 7 consecutive rheumatoid arthritis (RA) outpatients, using 2-D and 3-D ultrasound. Furthermore, we dissected two fresh-frozen postmortem hand specimens after US. A DAEM was observed in the metacarpophalangeal 2 (MCP2) joints of 54% of the 24 non-selected non-arthritic individuals; in none of those did the joint exhibit a power Doppler signal. A DAEM was observed in 86% of the 7 RA patients. Dimensions of DAEMs did not statistically significantly differ between these groups. At 3-D imaging and dissection, the DAEM was found to be an extension of the metacarpophalangeal joint capsule. In conclusion, DAEMs occur frequently and are not a sign of arthritis, but are distal joint recesses. This should be taken into account when using current sensitive ultrasonographic scoring systems grading arthritis.
authors.affiliation: Department of Rheumatology, Erasmus University Medical Center, Rotterdam, The Netherlands. Electronic address: d.tencate@erasmusmc.nl.
authors.forename: David Folkert
authors.initials: DF
authors.lastname: Ten Cate
authors.affiliation: Department of Rheumatology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Jolanda Jacoba
authors.initials: JJ
authors.lastname: Luime
authors.affiliation: Department of Rheumatology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Johanna Maria Wilhelmina
authors.initials: JM
authors.lastname: Hazes
authors.affiliation: Department of Neurosciences, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Gerrit-Jan
authors.initials: GJ
authors.lastname: Kleinrensink
authors.affiliation: Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, The Netherlands.
authors.forename: Johannes Wilhelmus Gerardus
authors.initials: JW
authors.lastname: Jacobs
mesh_terms: D000328:Adult; D000368:Aged; D001168:Arthritis / Q000000981:diagnostic imaging* / Q000473:pathology; D002102:Cadaver; D016022:Case-Control Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008662:Metacarpophalangeal Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D014463:Ultrasonography
keywords: Arthritis; False positive; Recess; Rheumatoid arthritis; Scoring protocol; Synovitis; Ultrasonography