Signal intensity changes of the posterior elements of the lumbar spine in symptomatic adults

MR imaging differentiating features between lytic and degenerative lumbosacral spondylolisthesis

Spondylolisthesis is characterized by the displacement of one vertebral body in relation to the adjacent vertebra. It is commonly observed in the lower lumbar region and can be caused by a variety of factors, including spondylolysis (a fracture in the pars interarticularis) or degenerative disease. Magnetic resonance imaging (MRI) is becoming increasingly popular as the primary modality for evaluation of low back pain and is often used in the absence of radiographs or Computed Tomography. However, it can be challenging for radiologists to differentiate between the two types of spondylolisthesis based on MRI alone. The goal of this article is to identify key imaging features on MRI that can aid radiologists in differentiating between spondylolysis and degenerative spondylolisthesis on MRI. Five key concepts are discussed: the "step-off" sign, the "wide canal" sign, T2 cortical bone signal on MRI, epidural fat interposition, and fluid in the facet joints. The utility, limitations and potential pitfalls of these concepts are also discussed to provide a comprehensive understanding of their use in differentiating between the two types of spondylolisthesis on MRI.

MRI lesions in SpA: a comparison with noninflammatory back pain using propensity score adjustment method

Background:

Magnetic resonance imaging (MRI) is important in the management of axial spondyloarthritis (SpA). However, many MRI lesions are not exclusive to axial SpA. Further characterization of these lesions may lead to better clinical decisions.

Objective:

The objective of this study was to compare the frequency of individual spinal MRI lesions between axial SpA and noninflammatory back pain. The factors associated with individual lesions in participants with axial SpA were also determined.

Design:

This was a cross-sectional observational study.

Methods:

MRI lesions in 447 participants with axial SpA and 122 participants with noninflammatory back pain were compared using the propensity score adjustment method. Individual lesions included discovertebral lesions (DVL), Modic type 1 lesions, DVL without Modic type 1 lesions, facet joint lesions, costovertebral joint lesions, corner inflammatory lesions (CIL), and fatty corner lesions (FCL). The factors associated with the lesions were determined using regression analyses.

Results:

Among participants with axial SpA, 81.9% were HLA-B27-positive, 55.0% had radiographic axial SpA, and 60.5% had radiographic features of spinal damage (mSASSS >2). Almost half (48.6% in axial SpA versus 31.1% in noninflammatory back pain) had inflammatory lesions on spinal MRI. In propensity score matching with noninflammatory back pain, axial SpA had an increased occurrence of DVL without Modic type 1 lesion (OR = 3.43, p = 0.01), costovertebral lesion (OR = 11.89, p = 0.02), number of CIL (B = 1.19, p < 0.001), and number of FCL (B = 3.33, p < 0.001). Similar associations were found in the regression models in the radiographic axial SpA subgroup: DVL without Modic type 1 lesion (OR = 2.46, p = 0.001), costovertebral lesion (OR = 3.86, p < 0.001), number of CIL (B = 1.13, p < 0.001), and FCL (B = 2.29, p < 0.01).

Conclusion:

MRI lesions including DVL without Modic type 1, costovertebral joint lesions, CIL, and FCL were more specific in axial SpA.