New Laser-Based Imaging for Early Diagnosis of Rheumatoid Arthritis

Study Documents Imaging Technique’s Accuracy in Detecting the Course of Finger Joint Inflammation

Findings Indicate Need to Combine Laser Imaging with Other Diagnostic Tools

A team of specialists in laser medicine has developed an imaging technique with the potential to dramatically improve the early diagnosis and treatment of Rheumatoid Arthritis (RA). According to the team’s study, which is published in the May 2002 issue of Arthritis & Rheumatism, this innovative laser-based technology can detect the course of finger joint inflammation in RA patients—with an accuracy rate of up to 83%.

A chronic, progressive disease, RA often leads to early disability and joint deformity. Recent studies have suggested that this devastating disease might well be prevented, or at least delayed, by early diagnosis and treatment. Given the widespread availability of effective therapeutic approaches, early diagnosis could change the quality of life for countless RA patients. Until now, conventional radiography has been the standard method of identifying destructive arthritis. This method, however, routinely overlooks early changes of erosion, the destructive process in cartilage and bone that can lead to deformity. While other imaging procedures, such as ultrasound or magnetic resonance imaging (MRI), offer possible alternatives for uncovering early evidence of arthritis and its progression, they have definite downsides. MRI can be costly and lacks standardization; ultrasound is time consuming and observers need training.

“The new laser imaging technique is easy to handle, inexpensive, and noninvasive,” attests research team leader Alexander K. Scheel. “It therefore has many advantages over conventional imaging and provides new information about joint status.”

The study was performed with an innovative laser device created by the Department of Medical Physics and Laser Medicine at the Free University of Berlin in cooperation with Siemens. Over a six-month period, 22 RA patients, ranging in age from 22 to 75 and representing both genders, committed to an ongoing examination of soft tissue changes and acute inflammation of their proximal finger joints. Positioned above the finger joint and working in conjunction with a sensitive camera, the laser device captured the optical characteristics of normal and inflamed joints then processed them through a picture software program. The inflammatory status of 60 of the 72 joints examined was classified correctly by laser imaging, confirmed through rigorous comparisons of hand radiographs and clinical evaluations. Researchers rated the laser technique 80% for sensitivity, 89% for specificity, and 83% for accuracy in detecting inflammatory changes in affected joints.

The results indicate that laser-based imaging can contribute significantly to diagnostic capabilities. Providing an affordable, accessible, and reproducible assessment of inflammatory joint changes, this unique imaging technique can help rheumatologists pinpoint RA of small finger joints and swiftly determine the most effective treatment.

Yet, Scheel and his team readily admit that laser imaging alone cannot replace other diagnostic methods. Although it can play a pivotal role in sensitive follow-up analysis of joint inflammation and provide important information about the response to medication, laser imaging, at this stage, only offers limited help for an individual diagnosis of early arthritis due to anatomic differences of the joint structures. Accurate diagnosis still depends on clinical examination, including measurements of joint circumference.

“Laser imaging may supplement our imaging armament and help us to better assess our arthritis patients,” Scheel observes. “However, additional studies with more patients and a comparison with other, established imaging techniques have to be performed before the overall usefulness of this new technology can be conclusively evaluated.”