RESEARCH - Does low-field dedicated extremity MRI reliably detect bone erosions in RA?

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Ann Rheum Dis. 2009 Aug;68(8):1296-302.

Does low-field dedicated extremity MRI (E-MRI) reliably detect bone

erosions in rheumatoid arthritis? A comparison of two different E-MRI

units and conventional radiography with high-resolution CT scanning.

Duer-Jensen A, Ejbjerg B, Albrecht-Beste E, Vestergaard A, Døhn UM,

Hetland ML, Østergaard M.

Department of Rheumatology, Copenhagen University Hospital,

Kettegaards Allé 30, 2635 Hvidovre, Denmark.

OBJECTIVES: To compare the ability of two different E-MRI units and

conventional radiography (CR) to identify bone erosions in rheumatoid

arthritis (RA) metacarpophalangeal (MCP) and wrist joints with CT

scanning as the standard reference method.

METHODS: 20 patients with RA and 5 controls underwent CR, CT and two

E-MRI examinations (Esaote Biomedica Artoscan and MagneVu MV1000) of

one hand during a 2-week period. In all modalities, each bone of the

wrist and MCP joints was blindly evaluated for erosions. MagneVu

images were also assessed for the proportion of each bone being

visualised.

RESULTS: 550 bones were examined. CT, Artoscan, MagneVu and CR

detected 188, 116, 55 and 45 bones with erosions, respectively. The

majority were located in the carpal bones. The sensitivity of the

Artoscan for detecting erosions was higher than that of the MagneVu

and CR (MCP joints: 0.68, 0.54 and 0.57, respectively; wrists: 0.50,

0.23 and 0.29). Corresponding specificities for detecting erosions

were 0.94, 0.93 and 0.99, respectively, in the MCP joints and 0.92,

0.98 and 0.98 in the wrist. The MagneVu allowed visualisation of 1.5

cm of the ventral-dorsal diameter of the bone. In the wrist, 31.6% of

bones were visualised entirely and 37.9% of bones were 67-99%

visualised. In MCP joints, 84.2% of bones were visualised entirely and

15.8% of bones were 67-99% visualised.

CONCLUSION: With CT as the reference method for detecting erosions in

RA hands, the Artoscan showed higher sensitivity than the MagneVu and

CR. All imaging modalities had high specificities. The better

performance of the Artoscan should be considered when selecting an

imaging method in RA.

PMID: 18718987

http://www.ncbi.nlm.nih.gov/pubmed/18718987

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