MR Imaging Assessment of Arthritis of the Knee

Bone marrow lesions and subchondral bone pathology of the knee

“…In inflammatory disease, erosions usually occur at tight recesses [32, 57]. More subtle differential diagnosis among types of arthritis has been reported in the literature [23]. BML also plays a prognostic role in rheumatoid arthritis, since it has been shown to be the strongest of many conventional and imaging biomarkers for prediction of erosive progression as well as an aggressive rheumatoid arthritis phenotype associated with functional decline [49].…”

Magnetic resonance imaging of the knee: An overview and update of conventional and state of the art imaging

“…T 2 hyperintense signal in the joint may be secondary to joint effusion or synovitis, which frequently coexist. Slight relative T 2 hypointensity compared to the joint fluid or a frond‐like appearance is suggestive of synovitis; adjustment of window and levels setting at the PACS workstation can help to make this distinction …”

“…Slight relative T 2 hypointensity compared to the joint fluid or a frond-like appearance is suggestive of synovitis; adjustment of window and levels setting at the PACS workstation can help to make this distinction. 71 Contrast-enhanced, fat-saturated images are best for evaluating the extent and degree of synovitis. The baseline degree of contrast enhancement in the synovium is somewhat variable 72 ; however, the presence of abundant enhancement in a frond-like pattern is consistent with synovitis.…”

Evaluation of the knee joint with ultrasound and magnetic resonance imaging

“…Fluid distention of the knee joint recesses by an effusion is a key marker of underlying joint pathology, including trauma, degeneration, inflammation, or infection. Both US and MRI permit detection of small amounts of fluid not readily apparent on physical examination and radiographs (5,6) . Identification of synovial hypertrophy further aids in the diagnosis of inflammatory and proliferative conditions, including pigmented villonodular synovitis and synovial chondromatosis (7) .…”

“…While effusions can be quickly evaluated and aspirated with US, there is often difficulty in distinguishing infected versus sterile effusions by imaging, as both may demonstrate synovial thickening and hyperemia, particularly in the setting of joint degeneration, inflammatory and metabolic arthropathies, or recent surgery (2) . Even though joint aspiration remains the primary approach to establishing the diagnosis, MRI offers added utility when the diagnosis cannot be readily established by aspiration or when complications are suspected, such as concomitant osteomyelitis and intra-osseous abscess (6) . While both MRI and US may demonstrate erosions, MRI provides a more detailed assessment for the presence and extent of articular cartilage destruction in the setting of aggressive infection (6,16) .…”