Optimization of dental implant imaging using photon-counting detector computed tomography in oral and maxillofacial surgery: an ex vivo study

OBJECTIVE: To determine optimal reconstruction parameters for dental implant imaging using photon-counting detector CT (PCD-CT), including ultra-high-resolution (UHR) images, virtual monoenergetic images (VMI), and iterative metal artifact reduction (iMAR). MATERIALS AND METHODS: In this ex vivo study, six pig mandibles were prepared with two titanium-based implants and imaged on a PCD-CT. Scans were reconstructed as UHR images and VMI from 70-190 keV at 10 keV increments with and without iMAR. Two independent readers qualitatively evaluated image quality and artifact severity using five-point visual rating scales (5 = excellent, no or minimal artifacts; and 1 = very poor, non-diagnostic, severe artifacts). Two readers quantified artifact severity, defined as the standard deviations in attenuation in regions of interest adjacent to the implants. RESULTS: UHR images without iMAR yielded high image quality (median 5 for both readers) with minor artifact severity (median 4 for both), whereas iMAR reduced image quality (median 3 for both). VMI without iMAR showed decreasing artifacts at higher energy levels. VMI at 120-130 keV achieved optimal image quality (median 5 for both readers at 120 keV, and medians 4 and 5 at 130 keV) with minimal artifacts (median 5 for both), whereas iMAR reduced quality. Quantitative artifact burden decreased with higher energy levels (from 200 HU at 70 keV to 113 HU at 190 keV), and no improvement was observed using iMAR. CONCLUSIONS: PCD-CT effectively reduces metal-induced artifacts in dental implant imaging, with UHR images and VMI at 120-130 keV providing optimal image quality, while reconstructions with iMAR offered no further benefit. RELEVANCE STATEMENT: PCD-CT provides excellent dental implant visualization while minimizing the impact of metal artifacts. KEY POINTS: In this ex vivo study, ultra-high-resolution images and virtual monoenergetic images at 120-130 keV from PCD-CT effectively reduce metal artifacts from dental implants. Effective artifact reduction offers excellent visualization of the bone-implant interface. Iterative metal artifact reduction (iMAR) did not provide additional benefit for visualization of the bone-implant interface.