Detection of Bone Marrow Edema Pattern With Dual-Energy Computed Tomography of the Pig Mandible Treated With Radiotherapy and Surgery Compared With Magnetic Resonance Imaging

Objective: The aim of the study was to investigate the accuracy of dual-energy computed tomography (DECT) compared with magnetic resonance (MR) imaging for the detection of edema of the mandible.Materials and methods: Fifteen adult Gottingen mini pigs received irradiation to the mandible with an equivalent dose of 0, 25, 50, or 70 Gy. Six months after irradiation, all animals underwent DECT and MR imaging of the mandible. Magnetic resonance short tau inversion recovery (STIR) was used for the grading of the bone marrow edema (0-3). Dual-energy CT (80 and 140 kVp) was performed, and virtual noncalcium (VNCa) images were calculated.Results: Increased signal intensity at STIR was found in the higher radiation groups. An increase of signal intensity in MR imaging was accompanied by a significant increase in the Hounsfield unit value of the VNCa images of the bone marrow (STIR: 0, 1, 2, 3; mean Hounsfield unit: -103, -90, -76, -34, respectively; P <0.05; R-2 = 0.388).Conclusions: The VNCa images derived from DECT are able to demonstrate bone marrow edema in radiation-induced bone changes in the mandible.