Short tau inversion recovery MRI of Modic changes: a reliability study

Abstract

Background: Limited reliability data exist for evaluation of spinal edema changes on magnetic resonance imaging (MRI) with short tau inversion recovery (STIR) sequences. Purpose: To assess the inter-observer reliability for evaluation of STIR signal increase related to Modic changes (MCs) on MRI of the lumbar spine. Material and Methods: We prospectively included 120 patients imaged to confirm their eligibility for the AIM (Antibiotics In Modic changes) trial. Three experienced radiologists independently evaluated MCs on T1-/T2-weighted fast spin-echo images and subsequently MC-related STIR signal increases. Inter-observer reliability was analyzed at four endplates (L4-S1) by calculating kappa values and means of differences with 95% limits of agreement. Results: Overall agreement (mean Fleiss' kappa for all endplates and observers) was very good for presence of STIR signal increase (0.86), and moderate for its categorized height (0.51), anteroposterior extent (0.48), and volume (0.56). For height of region with STIR signal increase measured in % points of vertebral body height, the largest mean of differences was 6.9 and widest range for limits of agreement was AE22.3 for all endplates combined. The corresponding numbers were 11.2 AE 34.5 for anteroposterior extent of the STIR signal increase measured in % points of anteroposterior endplate diameter and 0.9 AE 7.6 for its maximum measured intensity on a % point scale (0% ¼ normal vertebral marrow intensity, 100% ¼ cerebrospinal fluid intensity). Conclusion: Inter-observer reliability was very good for the presence and intensity of MC-related STIR signal increases, and moderate for their size.

Oedema on STIR modified the effect of amoxicillin as treatment for chronic low back pain with Modic changes—subgroup analysis of a randomized trial

“…The inversion time for STIR was 160 ms. Slice thickness/spacing was 4 mm/0.4 mm and field of view was 300 mm × 300 mm for all three sequences. Other MRI parameters were also identical between centres [ 33 ].…”

“…Three radiologists (A.E., N.V., and P.M.K.) who were blinded to clinical outcomes and treatment allocation independently rated MRI findings [ 33 ]. All had > 10 years of experience in musculoskeletal MRI.…”

“…The same three radiologists interpreted the MRIs from all study centres. On T1/T2, they rated primary (most extensive) and secondary MC types as type 1 (hypointense on T1, hyperintense on T2), type 2 (hyperintense on T1, iso- or hyperintense on T2), and type 3 (hypointense on T1 and T2) [ 33 ]. They evaluated the largest height and volume of MCs on T1/T2 and the largest height, volume and intensity of any MC-related STIR signal increase (Table 1 ), defined as a visible increase compared with normal vertebral bone marrow, located in or abutting a region with MC on T1/T2 or located and shaped as an MC [ 33 ].…”

“…if all three agreed there was a lesion to measure). The inter-rater reliability of the MRI evaluations was previously reported [ 33 ]. Fleiss’ kappa values [ 34 ] for overall inter-rater agreement (mean values across four endplates L4-S1) were 0.88/0.81 for presence of any MCs/type 1 MCs, 0.64/0.69 for MC height/volume, 0.86 for presence of a STIR signal increase, and 0.51/0.56 (0.40/0.40 at L5/S1 inferior to disc) for STIR signal height/volume.…”

“…if all three agreed there was a lesion to measure). The inter-rater reliability of the MRI evaluations was previously reported [33]. Fleiss' kappa values [34] for overall inter-rater agreement (mean values across four MRI, magnetic resonance imaging; MCs, Modic changes; STIR, short tau inversion recovery; T1/T2, T1-and T2-weighted fast spin echo images a STIR intensity < 25% included MCs with no conclusive STIR signal increase (or decreased STIR signal) and thus no conclusive measured STIR intensity values.…”