Simplified Universal Grading of Lumbar Spine MRI Degenerative Findings: Inter-Reader Agreement of Non-Radiologist Spine Experts

Abstract

Objective 1) To describe a simplified multidisciplinary grading system for the most clinically relevant lumbar spine degenerative changes. 2) To measure the inter-reader variability of non-radiologist spine experts in interpreting a consecutive series of lumbar spine MRI utilizing the classification. Methods A multidisciplinary and collaborative standardized grading of spinal stenosis, foraminal stenosis, lateral recess stenosis, and facet arthropathy was developed. Our institution’s PACS was searched for 50 consecutive patients who underwent non-contrast MRI lumbar spine for chronic back pain, radiculopathy, or symptoms of spinal stenosis. Three fellowship-trained spine subspecialists from neurosurgery, orthopedic surgery, and physiatry interpreted the 50 exams utilizing the classification at the L4-L5 and L5-S1 levels. Inter-reader agreement was assessed with Cohen’s kappa coefficient. Results For spinal stenosis, the readers demonstrated substantial agreement (k = 0.702). For foraminal stenosis and facet arthropathy the three readers demonstrated moderate agreement (k = 0.544, and 0.557, respectively). For lateral recess stenosis, there was fair agreement (k = 0.323). Conclusions A simplified universal grading system of lumbar spine MRI degenerative findings is newly described. Utilization of this multidisciplinary grading system in the assessment of clinically relevant degenerative changes revealed moderate to substantial agreement among non-radiologist spine physicians. This standardized grading system could serve as a foundation for interdisciplinary communication.

Grading Systems of Lumbar Facet Joint Inflammatory Changes on Magnetic Resonance Imaging

“…Finally, Miskin et al 20 reported the lowest Kappa value (0.56, 95% CI: 0.49–0.62) with a population of 50 subjects. They compared the readings of 3 neuroradiologists and 3 MSK radiologists 20. They analyzed the interreader agreement by comparing the prevalence of 4 parameters studied (foraminal stenosis, lateral recess stenosis, facet arthropathy, and spinal stenosis) per patient 20.…”

“…They classified these as FJ inflammation if periarticular or bone marrow edema was present 20. FJ periarticular or bone edema indicates a grade of 2 or 3 (depending on the presence of other features) in their grading system 20. Their system is distinguished from others because it includes morphologic changes, such as osteophytes, subchondral irregularity, or subchondral cysts, and inflammatory features embedded in the same system 20…”

“…The studies reported a range of measures to assess the interreader reliability (Kappa value, Cronbach alpha, and Krippendorf alpha value) 10,11,18–21. Czervionke and Fenton10 used the readings of a single neuroradiologist to perform their analysis and thus did not report interreader reliability measures.…”

“…While Lehman and colleagues analyzed these measures by comparing overall MRI scores assigned at the FJ level, Friedrich and colleagues studied the interreader reliability by comparing the change in intensity of FJ edema per patient 11,18. Finally, Miskin et al 20 reported the lowest Kappa value (0.56, 95% CI: 0.49–0.62) with a population of 50 subjects. They compared the readings of 3 neuroradiologists and 3 MSK radiologists 20.…”

“…In addition, the numerical grading scales differed across studies, and different visual cues and specific anatomic locations were used to identify edema. For example, Longmuir and Conley19 and Rodriguez et al 21 described the FJ signal localized exclusively within the joint space, while others characterized the signal response surrounding the joint 10,11,18,20. In addition, studies used different quantitative methods to measure interreader reliability, such as Kappa, Cronbach alpha, and Krippendorf alpha values.…”