Diagnosis of Infectious Spondylitis Using Non-Contrast Enhanced MRI With Axial Diffusion-Weighted Images: Comparison With Gadolinium-Enhanced MRI

ABSTRACT

Purpose@#To assess the diagnostic performances of diffusion-weighted imaging (DWI)-included non-contrast magnetic resonance imaging (MRI) compared to standard contrastenhanced MRI for infectious spondylitis. @*Materials and Methods@#This study involved 154 participants: a spondylitis group (n = 76) and a control group (n = 78) with Modic type 1 degeneration or recent compression fractures. Two readers independently reviewed paraspinal soft tissue signal change and abscess with 5-scale confidence scores based on two image sets: one featuring both non-contrast-enhanced MRI (NCEI) and DWI and the other consisting of NCEI and contrast-enhanced fat-suppressed T1-weighted imaging (CEFST1). The diagnostic performance of the two image sets was compared using McNemar tests for sensitivity, specificity, and area under the receiver operating characteristics (AUROC) analysis. Interobserver agreements (κ) for each images sets were also calculated. @*Results@#The sensitivity and specificity for infectious spondylitis were 90.8% and 69.2% for NCEI + DWI, 96.1% and 60.3% for NCEI + CEFST1 in reader 1, whereas it was 92.1% and 66.7% for NCEI + DWI, and 96.1% and 68.0% for NCEI + CEFST1 in reader 2. Sensitivities and specificities were not significantly different between NCEI + DWI and NCEI + CEFST1 (reader 1: p = 0.289, 0.065; reader 2: p = 0.250, > 0.999, respectively). However, the AUROC was not considerably different between the two modalities in only one reader (p = 0.306 in reader 1, p = 0.031 in reader 2). Interobserver agreement for infectious spondylitis was moderate (κ = 0.55) in NCEI + DWI and substantial (κ = 0.66) in NCEI + CEFST1. @*Conclusion@#Non-contrast enhanced MRI with additional DWI is as effective for diagnosing infectious spondylitis as a contrast-enhanced MRI.