Dual-Energy Computed Tomography-Based Display of Bone Marrow Edema in Incidental Vertebral Compression Fractures: Diagnostic Accuracy and Characterization in Oncological Patients Undergoing Routine Staging Computed Tomography

Purpose The aim of this study was to evaluate the diagnostic performance of virtual noncalcium (VNCa) dual-energy computed tomography (DECT) reconstructions enabling visualization of bone marrow edema for characterization of incidental thoracolumbar compression fractures in routine thoracoabdominal staging computed tomography (CT). Materials and Methods We retrospectively analyzed 51 oncological patients without suspected fracture or indicative complaints presenting at least 1 thoracolumbar compression fracture on routine thoracoabdominal staging DECT who had been examined between October 2015 and June 2017 using third-generation dual-source CT, had a previous CT within 3 months before, and also had undergone additional magnetic resonance imaging within 14 days, which served as the standard of reference. Three independent and blinded radiologists initially evaluated all vertebrae on conventional grayscale DECT series; after at least 8 weeks, observers reevaluated all cases using grayscale and color-coded VNCa DECT images. The age of each fracture was determined as either acute, chronic, or inconclusive. Specificity, sensitivity, and intraobserver and interobserver agreements were calculated taking into account clustering. Results A total of 98 vertebral compression fractures were detected in 51 patients (20 women, 31 men; median of 1 fracture per patient). The reference standard defined 45 as acute and 53 as chronic. For identification of only acute fractures (cutoff 1), the combination of grayscale and VNCa image series showed a higher sensitivity (91% vs 47%; P < 0.001) but equal specificity (both 100%) compared with analysis of grayscale images alone. When defining a positive finding as a fracture considered either acute or inconclusive (cutoff 2), combined analysis of grayscale and VNCa images showed similar sensitivity (96% vs 93%; P = 0.28) but significantly higher specificity (96% vs 75%; P < 0.001) compared with evaluation of grayscale images alone. Area under the curve analysis for detection of vertebral compression fractures showed superior results for reading of grayscale and VNCa image series (0.98) compared with analysis of grayscale images alone (0.89; P < 0.001). Conclusion Dual-energy CT-derived color-coded VNCa reconstructions substantially improve the characterization of incidental thoracolumbar compression fractures seen on routine thoracoabdominal staging DECT by allowing for visualization of bone marrow edema.