Fat-Saturated MR Imaging in the Detection of Inflammatory Facet Arthropathy (Facet Synovitis) in the Lumbar Spine

Abstract

Facet synovitis is a common condition and appears to correlate with the patient's pain. Detection of active inflammatory facet osteoarthropathy (facet synovitis) within and surrounding the facet joints is possible with MR imaging using a fat-saturation technique.

Facet Joint Signal Change on MRI at Levels of Acute/Subacute Lumbar Compression Fractures

“…Previous work has referred to this as inflammation, 6 which makes intuitive sense because facet joint inflammation is believed to be associated with pain resulting from a decreased threshold of nociceptor firing.…”

“…Facet joint signal change was graded by using an established scale of grades 0 -4 based on increasing osseous or soft-tissue signal abnormality at the facet joint (Table 1). 6 To be consistent with the scale as used by Czervionke and Fenton, 6 we graded a simple facet joint effusion without any other change zero because an effusion alone was not considered by these authors to necessarily indicate active inflammation or synovitis (personal communication L.F. Czervionke). All facet joints associated with the lumbar vertebral bodies were assessed individually, from the T12/L1 facet joints through the L5/S1 facet joints.…”

“…Although these signal changes have been previously referred to as inflammation, 6 the term "signal change" was used because the precise physiologic cause of this signal change is not known with certainty. Facet joint signal change was graded by using an established scale of grades 0 -4 based on increasing osseous or soft-tissue signal abnormality at the facet joint (Table 1).…”

“…3 While most literature indicates that chronic morphologic changes of facet joints are not predictive of facet joint pain, 4 there is evidence that facet joint inflammation manifest as bone scan activity, facet joint hyperintensity on fat-suppressed T2-weighted MR imaging, or facet joint enhancement on gadolinium-enhanced MR imaging is predictive. 5,6 MR imaging evidence of facet joint signal change, defined as T2 hyperintensity or enhancement on fat-suppressed images, adjacent to compression fractures has not been characterized to date, to our knowledge. We hypothesized that evidence of facet joint signal change on MR imaging is more common in facet joints associated with an acute/subacute lumbar compression fracture than in facet joints adjacent to vertebral bodies that are either normal or have a chronic compression fracture.…”

Comparison of facet joint activity on 99mTc-MDP SPECT/CT with facet joint signal change on MRI with fat suppression

“…However, this assertion is unproved; these studies used intra-articular injections, which have a high placebo rate, rather than comparative medial branch blocks, the standard diagnostic method for facet joint pain accepted by pain medicine physicians (7). Limited data also purport that T2 hyperintensity or gadolinium enhancement on MRI may be associated with painful facet joint arthropathy, although this is based on limited indirect evidence, rather than use of comparative medial branch blocks, and is also unproved (8).…”