Magnetic Resonance-Based Grading of Psoas and Paraspinal Muscle Edema: Is It Helpful in Diagnosing Lumbar Transverse Process Fractures?

Abstract

Purpose To determine the reliability of edema grading of the psoas and paraspinal muscles on axial T2-weighted magnetic resonance (MR) image (T2WI) for the detection of lumbar transverse process (TP) fractures. Materials and Methods A retrospective review of lumbar spine MR images of 56 patients (mean age = 56.1 years, age range = 17–87 years, male:female = 28:28) was conducted by 2 radiologists. Based on the axial T2WI at the disc level, the paraspinal muscles were classified into 4 compartments and muscle edema (increased signal intensity on axial T2WI) grading performed for each quadrant. Results A total of 486 TPs (with fracture: 24, without fracture: 462) of 56 patients were evaluated. Muscle edema grade showed moderate correlation with the presence of TP fracture (ρ = 0.466). When the total score of muscle edema was 2.50, the receiver operating characteristic curve showed a sensitivity of 72.7% and a specificity of 90.7%. A higher edema grade had a significantly higher probability of concomitant TP fracture [any sided (total): odds ratio = 1.704 (95% confidence interval = 1.410–2.060)]. Conclusion Edema grading of the psoas and paraspinal muscles on axial T2WI of lumbar spine can be helpful in the detection of TP fracture.

Keywords

• muscle
• edema
• lumbar vertebrae
• magnetic resonance imaging
• spinal fractures