Active Inflammatory Lesions Detected by Magnetic Resonance Imaging in the Spine of Patients with Spondyloarthritis - Definitions, Assessment System, and Reference Image Set

Abstract

Objective. Currently available magnetic resonance imaging (MRI) assessment systems for spine inflammation in patients with spondyloarthritis (SpA) identify only the overall inflammation in the discovertebral units. We aimed to develop and illustrate a detailed anatomy-based set of definitions and an assessment system for active inflammatory lesions in the spine of patients with SpA. Methods. MRI definitions of different inflammatory lesions at various anatomical locations in the spine, and an accompanying assessment system, were agreed by consensus within the Canada-Denmark MRI working group. Subsequently, a reference image set of representative examples of the individual pathologies, as well as borderline cases and important artefacts, were collected. Results. The defined lesions were (a) vertebral body inflammatory lesions, subdivided into corner, non-corner, massive, and lateral inflammatory lesions; and (b) vertebral inflammatory lesions not involving the vertebral body, subdivided into facet joint and other posterior element inflammatory lesions. All definitions were based on presence of increased signal intensity on sagittal T2-weighted fat-suppressed or STIR-images, as compared with the normal bone marrow signal. Vertebral body inflammatory lesions are assessed at each vertebral endplate at all 23 spinal levels from C2/3 to L5/S1, whereas facet joint or posterior element inflammatory lesions are to be assessed by segmental level (cervical, thoracic, and lumbar).Conclusion. An anatomy-based set of definitions and an assessment system for active inflammatory lesions in the spine of patients with SpA was developed and illustrated. The system is designed to study the temporal and spatial patterns of inflammation and their relation to the development of structural damage.

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

“…Specifically, MRI is subject to physiologic motion artifact, so that flowing blood in the inferior vena cava and the abdominal aorta may cause spurious signal that mimics anterior vertebral corner inflammatory lesions in the lumbar spine (23). Designating normal versus abnormal signal can be improved if normal signal intensity is defined and systematically applied together with the use of reference images depicting typical inflammatory lesions as well as lesions considered to be at the threshold of detection (18).…”

“…In reading the MR images, we adhered to standardized definitions for acute and chronic spinal lesions observed on MRI in patients with AS that were developed by the Spondyloarthritis 2216 CHIOWCHANWISAWAKIT ET AL Research Consortium of Canada (SPARCC) as well as an international working group of rheumatologists and radiologists from Canada and Denmark (16,18,22). For the purposes of this study, we have focused on the identification of focal fat infiltration and inflammation at the anterior corners of the vertebral bodies.…”

“…Reference images describing these lesions have been reported previously (16,18) and were available during the course of reading the MR images to facilitate evaluation of lesions considered to be at the threshold of detection.…”

“…It is evident as a focal increased signal in the bone marrow on T1-weighted images and as reduced signal on STIR images. However, increased T2 signal may be observed at the periphery of focal fat lesions, indicating that fat infiltration may follow the resolution of inflammation (18). Consequently, if vertebral corner inflammatory lesions are associated with new syndesmophytes, one might also predict that focal fat infiltration in a vertebral corner is more likely to be associated with the development of a de novo syndesmophyte than is a vertebral corner that appears normal.…”

Imaging Findings Suggestive of Axial Spondyloarthritis in Diffuse Idiopathic Skeletal Hyperostosis

“…Spine MRI inflammatory lesions were scored according to the Canada (Spondyloarthritis Research Consortium of Canada [SPARCC])-Denmark score (21,22). Briefly, each vertebral unit was divided into quadrants in which the presence/absence of inflammatory changes was noted (bone marrow edema [BME], with an intensity and depth note).…”