Fast kilovoltage peak-switching dual-energy computed tomography water-hydroxyapatite decomposition for detecting vertebral compression fracture-related bone marrow edema: a comparison with magnetic resonance imaging.

Background: Dual-energy computed tomography (DECT) material decomposition techniques have been reported to be effective for identifying acute and chronic vertebral compression fractures (VCFs) as compared with magnetic resonance imaging (MRI). However, a quantitative evaluation of the consistency of the bone marrow edema (BME) region depicted by DECT with that delineated by MRI has not been reported. This study thus aimed to qualitatively and quantitatively assess the fast kilovoltage peak (kVp)-switching DECT water-hydroxyapatite (HAP) decomposition technique in detecting traumatic BME in patients with VCFs and compare it to MRI.

Methods: A total of 195 consecutive patients who underwent both spinal DECT and MRI within 3 days from each other were retrospectively enrolled. All vertebral bodies were blindly evaluated for the presence of traumatic BME on water-HAP images. Water concentration was measured in all vertebral bodies, and the maximum area of BME was measured in the edematous ones. An experienced radiologist blindly evaluated the presence of BME on fluid-sensitive MR images, which served as the reference, and calculated the maximum area of BME. One-way analysis of variance with post hoc pairwise comparisons (Tamhane's T2 at P<0.05) was used to compare water concentrations among acute VCFs, chronic VCFs, and normal vertebrae. Receiver operating characteristic (ROC) curve analysis was conducted to predict acute VCFs. Bland-Altman analysis was performed to evaluate the consistency of the maximum area of BME measured on DECT and MRI.

Results: In the visual analysis of acute VCFs, water-HAP images had an overall sensitivity of 97.1%, a specificity of 99.7%, and an accuracy of 99.4%. Water concentration differed significantly between acute and chronic VCFs and between acute VCFs and normal vertebrae (P<0.001), but it did not differ significantly between chronic VCFs and normal vertebrae (P=0.998). ROC curve analysis yielded an area under the curve of 0.989, and the optimal threshold of 991.4 mg/cm³ yielded a 94.9% sensitivity and a 90.3% specificity in identifying edematous vertebral bodies. Bland-Altman plots indicated that all mean differences in the maximum area of BME measured on DECT and MRI were nearly zero (P>0.05), with most differences having a standard deviation within 1.96.

Conclusions: The fast kVp-switching DECT water-HAP decomposition technique had an excellent diagnostic performance in distinguishing acute VCFs from chronic ones. The depicted areas of BME on DECT and MRI were highly similar.