Dual-Energy Computed Tomography Virtual Noncalcium Imaging for the Detection of Acute Bone Marrow Edema in Vertebrae: Qualitative and Quantitative Analysis

Abstract

Purpose: To evaluate the feasibility of dual-energy computed tomography (DECT) virtual noncalcium (VNCa) images for detecting vertebral bone marrow edema (BME), both in qualitative and quantitative analyses. Materials and Methods: Nineteen cases with acute spinal trauma were enrolled. DECT and MR Imaging were performed over an interval of 0–3 days within 3 weeks of injury. Both gray-scale and color-coded VNCa images were evaluated in an independent and blind manner using a three-scale grading system (2 = distinct BME, 1 = suspicious BME, and 0 = no edema) by two radiologists. CT value of bone marrow were measured for each region and subjected to receiver operating characteristic (ROC) curve analysis for diagnosis of BME on VNCa images from DECT. Subsequently, as a standard of reference, MR imaging was evaluated by a third radiologist for the presence of traumatic BME. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the detection of BME using VNCa images were evaluated. Kappa analysis and one-way ANOVA were performed to evaluate the consistency and variance of VNCa images in the BME. Results: For two observers, the sensitivity of VNCa images for detecting BME (grade 2) were 97.8% and 96.7%, with the specificity 76% and 72%, the PPV 93.8% and 92.7%, the NPV 90.5% and 85.7%, respectively. And the sensitivity for detecting BME (grade 1–2) were 94.3% and 94.3%, with the specificity 96.7% and 93.3%, the PPV 98.8% and 97.6%, the NPV 85.3% and 84.8%, respectively. The consistency test between the two observers showed that Kappa value was 0.650 (P < 0.001). The VNCa images had higher CT value in the positive regions than in the negative regions (P < 0.05). Statistically significant differences in the CT value were identified in different regions with the three-scale grading system (thoracic levels: F = 136.690, P < 0.001; lumbar levels: F = 92.689, P < 0.001). Conclusions: Acute traumatic BME in the vertebrae can be detected on VNCa images in both qualitative and quantitative analyses. DECT VNCa images are expected to serve as an additional method for the evaluation of BME.