The diagnostic utility of magnetic resonance imaging in spondylarthritis: An international multicenter evaluation of one hundred eighty‐seven subjects

Abstract

Objective. To systematically assess the diagnostic utility of magnetic resonance imaging (MRI) to differentiate patients with spondylarthritis (SpA) from patients with nonspecific back pain and healthy volunteers, using a standardized evaluation of MR images of the sacroiliac joints.Methods. Five readers blinded to the patients and diagnoses independently assessed MRI scans (T1-weighted and STIR sequences) of the sacroiliac joints obtained from 187 subjects: 75 patients with ankylosing spondylitis (AS; symptom duration <10 years), 27 patients with preradiographic inflammatory back pain (IBP; mean symptom duration 29 months), 26 patients with nonspecific back pain, and 59 healthy control subjects; all participants were age 45 years or younger. Bone marrow edema, fat infiltration, erosion, and ankylosis were recorded according to standardized definitions using an online data entry system. We calculated sensitivity, specificity, and positive and negative likelihood ratios (LRs) for the diagnosis of SpA based on global assessment of the MRI scans.Results. Diagnostic utility was high for all 5 readers, both for patients with AS (sensitivity 0.90, specificity 0.97, positive LR 44.6) and for patients with preradiographic IBP (sensitivity 0.51, specificity 0.97, positive LR 26.0). Diagnostic utility based solely on detection of bone marrow edema enhanced sensitivity (67%) for patients with IBP but reduced specificity (88%); detection of erosions in addition to bone marrow edema further enhanced sensitivity (81%) without changing specificity. A single lesion of the sacroiliac joint on MRI was observed in up to 27% of control subjects.Conclusion. This systematic and standardized evaluation of sacroiliac joints in patients with SpA showed that MRI has much greater diagnostic utility than has been documented previously. We present for the first time a data-driven definition of MRI-visualized positivity for SpA.Diagnosing early spondylarthritis (SpA) in young patients presenting with symptoms of inflammatory back pain (IBP) and normal findings on plain radiographs of the sacroiliac (SI) joints remains a challenge in routine practice. Radiography detects postinflammatory structural changes in the subchondral bone of the SI joints, but changes may become evident only after a symptom duration of several years (1,2). Magnetic resonance imaging (MRI) is capable of detecting inflammatory changes in bone marrow and soft tissue and is now widely accepted as the most sensitive imaging modality for detecting sacroiliitis, the hallmark of SpA. Therefore, MRI may be able to detect abnormalities in the SI

Development and Validation of a Magnetic Resonance Imaging Reference Criterion for Defining a Positive Sacroiliac Joint Magnetic Resonance Imaging Finding in Spondyloarthritis

“…The technical parameters for the STIR and T1SE sequences of semicoronal MR SI joint scans performed at both institutions have been described previously (3). The MRIs were read and scored independently by 4 readers (1 radiologist [VZ] and 3 rheumatologists [SJP, UW, WPM]) blinded to the diagnosis and patient identifiers.…”

“…The evaluation of the MRIs followed a standardized module (10) comprising 2 sections: first, a global assessment indicating the presence or absence of SpA according to all MRI findings on both sequences, and second, a scoring section indicating the number of SI joint quadrants affected by different MRI lesions according to standardized lesion definitions (3).…”

“…The definition of a positive SI joint MRI finding in the ASAS criteria was generated by consensus among experts and is entirely based on the presence of bone marrow edema (BME) on the STIR sequence or osteitis on the T1-weighted gadoliniumenhanced sequence (2). Studies using a data-driven approach to defining a positive SI joint MRI finding are scarce (3). Moreover, there is growing evidence that structural lesions may contribute substantially to the diagnostic utility of SI joint MRI in nonradiographic axial SpA (nr-axSpA) (4,5).…”

Focal fat lesions at vertebral corners on magnetic resonance imaging predict the development of new syndesmophytes in ankylosing spondylitis

“…MRI has also shown that fat infiltration is a frequent finding both in the sacroiliac joints and in the spine at locations where inflammation is typically observed (15)(16)(17). It is evident as a focal increased signal in the bone marrow on T1-weighted images and as reduced signal on STIR images.…”

The Concept of Axial Spondyloarthritis: Joint Statement of the Spondyloarthritis Research and Treatment Network and the Assessment of SpondyloArthritis international Society in Response to the US Food and Drug Administration's Comments and Concerns

“…The MRI result might be false-positive or false-negative (18). Depending only on MRI findings is not advisable, and pretest probability should be taken into account when making the diagnosis (24).…”