Dental imaging using an ultra-high resolution photon-counting CT system

Ruetters, Maurice; Şen, Sinan; Gehrig, Holger; Brückner, Thomas; Kim, Ti‐Sun; Lux, Christopher J.; Heinze, Sarah; Maier, Joscha; Kachelrieß, Marc; Sawall, Stefan

doi:10.1038/s41598-022-11281-x

Cited by 13 publications

(17 citation statements)

References 31 publications

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“…To our knowledge, only two studies exist assessing the application of PCCT for visualizing the dentoalveolar region 9 , 20 . Vanden Broeke et al evaluated the feasibility of using PCCT to detect accessory root canals and the expression of metal artefacts generated by dental implants compared to CBCT and micro-CT imaging 20 .…”

Section: Discussionmentioning

confidence: 99%

“…Unlike present study, where a phantom covered with soft-tissue equivalent was used which could be considered more acceptable for replicating a clinical scenario. In another study, the ability of PCCT was investigated for qualitatively delineating cortical and medullary bone, root canals, periodontal space, and apical osteolysis using cadaveric heads 9 . In addition, the authors also assessed the device’s performance for measuring vertical bone loss and buccal cortical plate thickness.…”

Section: Discussionmentioning

confidence: 99%

“…As this study confirmed the outstanding performance of PCCT for appropriate or acceptable visualization of fine endodontic structures and root cracks, it could act as a reliable imaging source for endodontic tasks in patients who have previously underwent PCCT imaging of the head and neck region indicated for other medical reasons. Hence, inhibiting the need for CBCT scanning and in turn further reducing the patient's exposure to ionizing radiation 9 .…”

Section: Discussionmentioning

confidence: 99%

“…This allows each absorbed x-ray photon to generate a charge cloud which is individually transported to the detector pixels by applying a bias voltage. Thereby, generating an electrical signal and dismissing an initial transformation into visible light which happens with CT detectors composed of conventional energy-integrating scintillator materials 9 , 10 . As no scintillator layer and reflecting lamellae exist in the PCCT detectors, their pixel size is smaller compared to conventional CT detectors which increases the image resolution 8 , 10 .…”

Section: Introductionmentioning

confidence: 99%

“…A recent in vitro study showed optimal performance of PCCT compared to CBCT imaging for different diagnostic tasks in the field of dentistry, which included detection of apical osteolysis, measurement of bone thickness and visualization of various dental structures and surrounding bone 9 . However, to our knowledge, the performance of PCCT for assessing challenging diagnostic tasks in endodontics has not yet been investigated.…”

Section: Introductionmentioning

confidence: 99%

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Feasibility of photon-counting computed tomography as a novel imaging modality for challenging endodontic diagnostic tasks

Fontenele

Pícoli

Pinto

et al. 2023

Sci Rep

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Photon-counting computed tomography (PCCT) is an innovative technological advancement in relation to x-ray detectors which offers ultra-high-resolution images. The current study aimed to evaluate the visualization ability of PCCT compared to cone-beam computed tomographic (CBCT) devices for challenging endodontic diagnostic tasks. A reference image of an anthropomorphic phantom was acquired using an industrial micro-CT device. Thereafter, the phantom was scanned with three imaging devices, which included PCCT scanner (NAEOTOM Alpha) and two CBCT devices (3D Accuitomo 170 and NewTom VGi evo) having standard and high-resolution acquisition protocols. The diagnostic tasks involved visualizing fine endodontic structures (apical delta, narrow canal, and isthmus) and root cracks. Three experienced examiners assessed the images and were blinded to the PCCT and CBCT devices. Each image was rated according to a three-grade scale (appropriate, acceptable, or inappropriate) for the diagnostic tasks. In relation to fine endodontic structures grouped together, PCCT showed similar diagnostic performance compared to the reference image (p > 0.05). As for the CBCT devices, an excellent performance was only observed with the 3D Accuitomo 170 device at a high-resolution acquisition mode (p > 0.05). The visualization of root cracks was also better with 3D Accuitomo 170 compared to other devices (p < 0.05). Overall, PCCT and 3D Accuitomo 170 at a high-resolution setting showed similar performance for visualizing fine endodontic structures. In addition, the high-resolution CBCT protocol was superior for visualizing root cracks compared to both PCCT and other standard- and high-resolution CBCT protocols.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Feasibility of photon-counting computed tomography as a novel imaging modality for challenging endodontic diagnostic tasks

Fontenele

Pícoli

Pinto

et al. 2023

Sci Rep

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Likelihood‐based bilateral filters for pre‐estimated basis sinograms using photon‐counting CT

Lee

2023

Medical Physics

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Background Noise amplification in material decomposition is an issue for exploiting photon‐counting computed tomography (PCCT). Regularization techniques and neighborhood filters have been widely used, but degraded spatial resolution and bias are concerns. Purpose This paper proposes likelihood‐based bilateral filters that can be applied to pre‐estimated basis sinograms to reduce the noise while minimally affecting spatial resolution and accuracy. Methods The proposed method needs system models (e.g., incident spectrum, detector response) to calculate the likelihood. First, it performs maximum likelihood (ML)‐based estimation in the projection domain to obtain basis sinograms. The estimated basis sinograms suffer from severe noise but are asymptotically unbiased without degrading spatial resolution. Then it calculates the neighborhood likelihoods for a given measurement at the center pixel using the neighborhood estimates and designs the weights based on the distance of likelihoods. It is also analyzed in terms of statistical inference, and then two variations of the filter are introduced: one that requires the significance level instead of the empirical hyperparameter. The other is a measurement‐based filter, which can be applied when accurate estimates are given without the system models. The proposed methods were validated by analyzing the local property of noise and spatial resolution and the global trend of noise and bias using numerical thorax and abdominal phantoms for a two‐material decomposition (water and bone). They were compared to the conventional neighborhood filters and the model‐based iterative reconstruction with an edge‐preserving penalty applied in the basis images. Results The proposed method showed comparable or superior performance for the local and global properties to conventional methods in many cases. The thorax phantom: The full width at half maximum (FWHM) decreased by −2%–31% (−2 indicates that it increased by 2% compared to the best performance from conventional methods), and the global bias was reduced by 2%–19% compared to other methods for similar noise levels (local: 51% of the ML, global: 49%) in the water basis image. The FWHM decreased by 8%–31%, and the global bias was reduced by 9%–44% for similar noise levels (local: 44% of the ML, global: 36%) in the CT image at 65 keV. The abdominal phantom: The FWHM decreased by 10%–32%, and the global bias was reduced by 3%–35% compared to other methods for similar noise levels (local: 66% of the ML, global: 67%) in the water basis image. The FWHM decreased by up to −11%–47%, and the global bias was reduced by 13%–35% for similar noise levels (local: 71% of the ML, global: 70%) in the CT image at 60 keV. Conclusions This paper introduced the likelihood‐based bilateral filters as a post‐processing method applied to the ML‐based estimates of basis sinograms. The proposed filters effectively reduced the noise in the basis images and the synthesized monochromatic CT images. It showed the potential of using likelihood‐based filters ...

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Diagnostische Radiologie

Lennartz

Persigehl

2022

Onkologie

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Dental imaging using an ultra-high resolution photon-counting CT system

Cited by 13 publications

References 31 publications

Feasibility of photon-counting computed tomography as a novel imaging modality for challenging endodontic diagnostic tasks

Feasibility of photon-counting computed tomography as a novel imaging modality for challenging endodontic diagnostic tasks

Likelihood‐based bilateral filters for pre‐estimated basis sinograms using photon‐counting CT

Diagnostische Radiologie

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