RESEARCH - Detection of RA bone erosions by two different MRI units and conventional radiography

[Guest guest]

Published Online First: 5 November 2007. doi:10.1136/ard.2007.076026

ls of the Rheumatic Diseases 2008;67:998-1003

--------------------------------------------------------------------------------

EXTENDED REPORTS

Detection of rheumatoid arthritis bone erosions by two different

dedicated extremity MRI units and conventional radiography

A Duer-Jensen 1, A Vestergaard 2, U M Døhn 1, B Ejbjerg 3, M L Hetland

1, E Albrecht-Beste 2, M Østergaard 4

1 Department of Rheumatology, Copenhagen University Hospital at

Hvidovre, Denmark

2 Department of Radiology, Copenhagen University Hospital at Hvidovre, Denmark

3 Department of Rheumatology, Copenhagen University Hospital at

Frederiksberg, Denmark

4 Departments of Rheumatology, Copenhagen University Hospitals at

Hvidovre and Herlev, Denmark

Objectives: To compare the ability of two different dedicated

extremity MRI (E-MRI) units and conventional radiography (CR) for

identifying bone erosions in rheumatoid arthritis (RA)

metacarpophalangeal (MCP) and wrist joints.

Methods: CR and two MRI examinations (using 0.2 T Esaote Artoscan and

0.2 T portable MagneVu MV1000 units) of 418 bones in the dominant

wrist and second to fifth MCP joints of 15 patients with RA and 4

healthy controls were performed and evaluated blindly for bones being

visible and for erosions.

Results: In MCP joints, MagneVu visualised 18.5% of bones entirely and

71.1% were 67–99% visualised. In wrists, MagneVu visualised 1.5% of

bones entirely, 39.8% were 67–99% visualised and 19% were not

visualised at all. Artoscan and CR visualised all bones entirely.

Artoscan, MagneVu and CR found 22, 19 and 15 bones with erosions in

MCP joints and 66, 40 and 13 bones with erosions in wrist joints,

respectively. With the previously validated Artoscan unit as standard

reference, MagneVu and CR had sensitivities of 0.82 and 0.55,

respectively, in MCP joint bones and 0.41 and 0.14 in wrist bones.

Specificities of CR and MagneVu were comparable (0.82–0.99). The

MagneVu unit was particularly more sensitive than CR for metacarpal

heads and carpal bones. MagneVu MRI and CR detected 100% and 89%,

respectively, of large erosions (Outcome Measures in Rheumatoid

Arthritis Clinical Trials–Rheumatoid Arthritis MRI Scoring System

(OMERACT-RAMRIS) score >1 on Artoscan) in MCP joints and 69% and 15.8%

of large erosions in wrists.

Conclusions: Both E-MRI units detected more erosions than CR, in

particular due to a higher sensitivity in metacarpal heads and carpal

bones. The MagneVu unit detected fewer erosions than the Artoscan unit

due to a lower average image quality and a smaller proportion of bones

being visualised.

--------------------------------------------------------------------------------

http://ard.bmj.com/cgi/content/abstract/67/7/998?etoc

--

Not an MD