MRI is best for hand imaging in RA

[Guest guest]

Oct 11, 2002

MRI is best for hand imaging in RA

A new study and accompanying leader in this month's ls of Rheumatic

Diseases discuss the pros and cons of the various techniques available for

imaging of the hand and wrist in rheumatoid arthritis[1,2].

Conventional x-rays are no good for detecting early erosions in RA but still

have a role to play in the basic investigation of the disease, the

researchers say. Ultrasound, while inexpensive, has a drawback in that only

trained doctors can perform it, while magnetic resonance imaging (MRI) seems

to offer the best image quality but is very expensive, they note.

Dr Marina Backhaus (Charité University Hospital, Humboldt University of

Berlin, Germany) and colleagues compared imaging techniques for monitoring

the course of erosions over a 2-year follow-up period in 49 patients with

arthritic finger joints. As well as comparing conventional radiography,

ultrasound, and MRI, they looked at whole 3-phase bone scintigraphy.

They explain some of the differences in cost and time required to perform

these techniques. Conventional radiography costs €33, ultrasonography around

€27, and MRI and scintigraphy both cost approximately €200. Conventional

X-rays take about 5 minutes to perform, ultrasound takes 15 minutes, MRI

about 13 minutes, and scintigraphy 10 minutes. The time needed for

interpretation and reporting of the results by a doctor is about 10 to 15

minutes for each of the procedures.

Ultrasound not as good as MRI

Their results indicate that " conventional radiography is not sensitive

enough for assessing early arthritis, " they say. Ultrasound " is an excellent

modality for depicting signs of soft tissue inflammation. . . . [it]

demonstrates erosions before they are seen by conventional radiography,

though not to the same extent as MRI. " In the accompanying leader, Dr Bachir

Taouli (University of California San Francisco) and colleagues say that

ultrasound " is too operator dependent to be used generally, " although they

acknowledge that it can be " useful " in experienced hands.

" Ultrasound 'is an excellent modality for depicting signs of soft tissue

inflammation . . . but is too operator dependent to be used generally.' "

Bachaus et al say that 3-phase bone scintigraphy is " a good screening

modality [and] is very helpful in patients requiring whole body assessment, "

but because of its low specificity, it " is not suitable for the detection of

early erosions. "

Major drawbacks of MRI are cost and limited availability

MRI " is a sensitive method for detecting both soft tissue lesions and early

erosions in arthritis. Its role is in the diagnostic assessment of early

arthritis in patients with negative radiographic findings with whom more

aggressive treatment should be discussed. It may furthermore have an

important role in short-term and intermediate-term treatment studies with

biological agents or other drugs. "

" The role of MRI 'is in the diagnostic assessment of early arthritis in

patients with negative radiographic findings with whom more aggressive

treatment should be discussed.' "

Taouli and colleagues observe that MRI " offers distinct advantages over

radiography: in addition to its multiplanar capability, it has the ability

to directly image the soft tissues . . . as well as bone, cartilage, and

tendons. We believe that MRI has a potential role in the initial patient

management, at least for identifying those patients at risk of structural

damage. " However, " the major drawbacks of MRI are its high cost and limited

availability, " they say.

Nainggolan