Standard Operating Procedures Established for Spinal Imaging Protocols

The Back Pain Consortium Spine Imaging Working Group has published standard operating procedures for spinal imaging protocols in Pain Medicine.

Eligible patients with chronic low back pain should undergo magnetic resonance imaging (MRI) of the lumbosacral spine in a supine position using a spine coil or table-embedded coil array. The authors recommended using a minimal pulse sequence protocol of sagittal T2-weighted fast spin echo with fat suppression, sagittal T1-weighted fast spin echo without fat suppression, and axial T2-weighted fast spin echo without fat suppression.

If feasible, the authors recommend sagittal T2-weighted fast spin echo without fat suppression, sagittal T1-weighted fast spin echo without fat suppression covering the sacroiliac joints, coronal T1-weighted fast spin echo without fat suppression covering the sacroiliac joints, axial T1-weighted fast spin echo without fat suppression, and MR neurography of the lumbosacral plexus using 3-dimensional T2-weighted fast spin echo with fat suppression.

When evaluating the imaging data, clinicians should look for modic-type endplate changes, endplate defects, intervertebral disc changes, facet joint and lumbosacral plexus changes, and stenosis.

For modic changes, type 1 changes are typically inflammatory, type 2 changes are related to fatty degenerative remodeling, and type 3 changes are sclerotic. The literature reports excellent intra-rater agreement for evaluating modic-type endplate changes; however, sensitivity is low.

Endplate defects are scored according to their appearance. Clinicians should consider the shape, size, and depth when scoring these defects.

Disc degeneration should be graded using the Pfirrmann classification, which uses 5 grades. Grade 1 is a homogeneous disc with normal height and bright hyperintense white signal. Grade 5 is an inhomogeneous disc with a collapsed disc space and hypointense black signal. This classification system has excellent inter- and intra-rater reliability.

Facet and sacroiliac joint changes are typically characterized by hypertrophy of the articular processes, formation of osteophytes, and reduction in the joint space. Clinicians should be aware that grading these joint changes has a weak inter-rater reliability.

Evaluation of central canal stenosis is achieved by assessing the contour of the thecal sac and the amount of cerebrospinal fluid space around the spinal cord.

Study authors concluded, “Management of patients suffering from low back pain is challenging and requires development of diagnostic techniques to identify specific patient subgroups and phenotypes in order to customize treatment and predict clinical outcome. While lumbar MRI is frequently performed in patients with low back pain, it has not yet developed into a reliable and standardized tool for these purposes.”