The use of 16-channel hand coil MRI to examine flexor tendon pulley changes may improve the detection of psoriatic arthritis (PsA) and distinguish it from rheumatoid arthritis (RA), according to research results published in BMC.
Researchers evaluated the value of changes in flexor tendon pulleys on 3 Tesla MRI using a novel 16-channel high-resolution hand coil to differentiate between RA and PsA. A total of 17 patients with active PsA (mean age, 53.7±11.6 years; 9 men), 20 patients with active RA (therapy-naive; mean disease duration <6 months; mean age 46±15.7 years; 9 men) who met the American College of Rheumatology/European League Against Rheumatism 2010 criteria for the disease, and 16 healthy control individuals (mean age 39±16.1 years; 9 men) were enrolled.
Patients with PsA underwent baseline and follow-up MRI scans with an approximate 6.2±0.85-month interval between scans; patients with RA underwent baseline and 2 follow-up scans with approximately 2.8±0.1 months between the baseline and first scans and 5.6±0.1 months between baseline and the second scans. Healthy controls underwent only 1 MRI scan. MRI images were independently analyzed by 2 radiologists, who evaluated flexor tendon pulleys A1 and A2 in digits 2 to 5. Each pulley was evaluated in terms of thickness (in millimeters), as well as intrinsic and/or surrounding signal intensity at the radial, ulnar, and volar aspects.
The most common findings in all patients, irrespective of diagnosis, were synovitis, flexor tenosynovitis, and periarticular inflammation. Bone edema and erosion were not as common, and bone proliferation was rarely detected. In patients with PsA vs RA, both periarticular inflammation and bone erosion were significantly more frequently detected.
Compared with patients with RA and healthy control participants, patients with PsA had significantly thicker A1 and A2 flexor tendon pulleys in most fingers (overall mean difference: RA, 0.19 mm; P <.001; control participants, 0.16 mm; P <.001). Compared with control participants, patients with PsA had significantly more inflammatory changes at the A1 and A2 flexor tendon pulleys in all fingers (mean difference, 14.65; P <.001). Thickness was similar in patients with RA vs control participants, but their pulleys had more intense inflammatory changes (mean difference, 9.95; P <.001).
A strong correlation was identified in patients with PsA between pulley inflammation and overall PsA MRI score, as well as between pulley inflammation and inflammatory PsA MRI subscores in most fingers. A low to high heterogeneous correlation was also identified between pulley inflammation, bone erosion, and edema in patients with PsA, in whom the correlation between pulley inflammation and bone proliferation was weak. In patients with RA, significant but weaker correlations were established between pulley inflammation and overall PsA MRI score and subscores.
Study limitations included a small cohort, the difference in mean disease duration between the RA and PsA groups, and the decision not to systematically count swollen and tender joints at the time of recruitment, limiting the ability to examine the relationship between inflammatory pulley changes and clinical manifestations of disease.
“The assessment of high-resolution MRI changes of flexor tendon pulleys using a 16-channel hand coil could be used for disease detection in PsA, and is potentially beneficial for the distinction from RA and [healthy control participants],” the researchers concluded.
Disclosure: This clinical trial was supported by Pfizer Germany and AbbVie Deutschland GmbH & Co. Please see the original reference for a full list of authors’ disclosures.
Abrar DB, Schleich C, Nebelung S, et al. High-resolution MRI of flexor tendon pulleys using a 16-channel hand coil: Disease detection and differentiation of psoriatic and rheumatoid arthritis. Arthritis Res Ther. 2020;22(1):40.