Dual-energy cone-beam CT improves iodine contrast and Hounsfield unit value stability in the maxillofacial region: a phantom study
TL;DR
Although DE-CBCT with VMI and frequency splitting improves HU agreement with CT, slightly improves soft tissue visualization, and reduces artifacts in head and neck phantom imaging, it did not reveal any additional targets compared with routine CBCT.
Abstract
This study was designed to assess the feasibility of dual-energy cone-beam computed tomography (DE-CBCT) and the associated image processing algorithms to improve delayed phase iodine enhancement. An anthropomorphic adult head phantom with iodine inserts in maxillofacial regions was imaged using a clinical CBCT and a helical CT scanner. DE-CBCT was acquired sequentially at 80 and 120 kV, and helical CT at 100 kV (routine clinical protocol), with radiation doses matched within 5%. Virtual monochromatic images (VMIs) at 50 and 200 keV were generated with (VMI+) and without (VMI) noise-optimized frequency splitting algorithm. Evaluation included Hounsfield Unit (HU) agreement with helical CT, iodine contrast, contrast-to-noise ratio (CNR), artifact reduction, and subjective radiologist assessment of target visibility. VMI50 and VMI50+ demonstrated the strongest HU agreement with CT. VMI50+ produced significantly better contrast than CBCT in the maxillary sinus region (mean percentage change 40.7% (15.3%–66.1%); p < 0.05), while improvements were minor in the mandibular region (9.7% (3.0%–16.5%); p < 0.05). VMI50+ significantly increased CNR in the maxillary sinus compared with CBCT (3.3 vs 2.8; p < 0.05), with no significant difference in the mandibular region. Although DE-CBCT increased contrast and reduced artifacts, it did not reveal any additional targets compared with routine CBCT. DE-CBCT with VMI and frequency splitting improves HU agreement with CT, slightly improves soft tissue visualization, and reduces artifacts in head and neck phantom imaging.