Magnetic Resonance Imaging of Sacroiliitis in Patients with Spondyloarthritis: Correlation with Anatomy and Histology

Abstract

Magnetic resonance imaging (MRI) of the sacroiliac joints (SIJs) has become established as a valuable modality for the early diagnosis of sacroiliitis in patients with inconclusive radiographic findings. Positive MRI findings have the same significance as a positive test for HLA-B27. Sacroiliitis is one of the key features of axial spondyloarthritis (SpA) in the classification proposed by the Assessments in Ankylosing Spondylitis (ASAS) group.?Early signs of sacroiliitis include enthesitis of articular fibrocartilage, capsulitis, and osteitis. In more advanced disease, structural (chronic) lesions will be visible, including periarticular fatty deposition, erosions, subchondral sclerosis, and transarticular bone buds and bridges. In this article we describe magnetic resonance (MR) findings and provide histologic biopsy specimens of the respective disease stages. The predominant histologic feature of early and active sacroiliitis is the destruction of cartilage and bone by proliferations consisting of fibroblasts and fibrocytes, T-cells, and macrophages. Advanced sacroiliitis is characterized by new bone formation with enclosed cartilaginous islands and residual cellular infiltrations, which may ultimately lead to complete ankylosis. Knowledge of the morphologic appearance of the sacroiliac joints and their abnormal microscopic and gross anatomy is helpful in correctly interpreting MR findings. Citation Format: ??Hermann KGA, Bollow M. Magnetic Resonance Imaging of Sacroiliitis in Patients with Spondyloarthritis: Correlation with Anatomy and Histology. Fortschr R?ntgenstr 2014; 186: 230???237

Does Level of Response to SI Joint Block Predict Response to SI Joint Fusion?

“…Multiple studies, summarized in a recent systematic review, 9 have indicated that the occurrence of at least 3 positive physical examination signs in patients suspected of having SIJ dysfunction was highly predictive of their response to SIJB. In contrast to lumbar spine conditions in which imaging is considered to be critical for diagnosis, the painful SIJ is not associated with characteristic findings on plain radiographic or cross-sectional imaging with the exception being inflammatory findings in patients with seropositive 10 or seronegative 11 autoimmune spondyloarthropathies. At this time, plain radiographic and cross-sectional imaging are largely used to rule out other competing diagnoses, leaving SIJB as the de facto current standard for the confirmation of SIJ dysfunction preliminarily made based upon the history and physical exam.…”

CT-guided corticosteroid injection of the sacroiliac joints: quality assurance and standardized prospective evaluation of long-term effectiveness over six months

“…The sacroiliac compartment can be divided into the anterior cartilaginous part of the joint with synovial tissue and a joint capsule and the posterior retroarticular space containing interosseous ligaments and fatty connective tissue [6] ( Fig. 1).…”

“…Due to the complex and variable anatomy of the sacroiliac joint (SIJ), a local treatment remains a therapeutic and technical challenge [5,6]. SIJ injection is used for local pain relief in sacroiliitis in combination with first-line systemic therapies including nonsteroidal anti-inflammatory drugs (NSAIDs) and biologic agents [7].…”

Fat Metaplasia in Inflammatory Sacroiliitis and in Nonrheumatic Conditions: A Step Toward Better Characterization

“…To date, MRI is considered the most sensitive and specific imaging modality for diagnosing and evaluating SIJ inflammation in patients with early disease 4 . The introduction of biological drugs such as the tumor necrosis factor-α receptor blocker group and their beneficial effect on SpA resulted in an accelerated use of MRI for early detection of sacroiliitis 4,5 .…”

“…The introduction of biological drugs such as the tumor necrosis factor-α receptor blocker group and their beneficial effect on SpA resulted in an accelerated use of MRI for early detection of sacroiliitis 4,5 . As a result, an increasing number of SIJ MRI are performed each year on patients with suspected sacroiliitis 6 .…”