Improved visualization of the wrist at lower radiation dose with photon-counting-detector CT

Rajendran, Kishore; Baffour, Francis; Powell, Garret M.; Glazebrook, Katrina N.; Thorne, Jamison; Larson, Nicholas B.; Leng, Shuai; McCollough, Cynthia H.; Fletcher, Joel G.

doi:10.1007/s00256-022-04117-2

Cited by 45 publications

(36 citation statements)

References 23 publications

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“…This approach enables quantitation of trabecular morphology such as trabecular thickness, spacing, number, and bone volume fraction in central sites such as spine and large joints using PCD-CT, which were previously limited to extremities using peripheral quantitative CT. Bone CT numbers in PCD-CT are significantly higher than those obtained using EID-CT, 76,77 due to count weighting instead of energy weighting in PCDs. This increase in bone contrast, combined with decreased partial volume averaging from smaller detector pixels of PCD-CT, leads to better depiction of fine trabecular structures and osseous pathology.…”

Section: Musculoskeletal Anatomymentioning

confidence: 88%

Standardization and Quantitative Imaging With Photon-Counting Detector CT

2023

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Computed tomography (CT) images display anatomic structures across 3 dimensions and are highly quantitative; they are the reference standard for 3-dimensional geometric measurements and are used for 3-dimensional printing of anatomic models and custom implants, as well as for radiation therapy treatment planning. The pixel intensity in CT images represents the linear x-ray attenuation coefficient of the imaged materials after linearly scaling the coefficients into a quantity known as CT numbers that is conveyed in Hounsfield units. When measured with the same scanner model, acquisition, and reconstruction parameters, the mean CT number of a material is highly reproducible, and quantitative applications of CT scanning that rely on the measured CT number, such as for assessing bone mineral density or coronary artery calcification, are well established. However, the strong dependence of CT numbers on x-ray beam spectra limits quantitative applications and standardization from achieving robust widespread success. This article reviews several quantitative applications of CT and the challenges they face, and describes the benefits brought by photon-counting detector (PCD) CT technology. The discussed benefits of PCD-CT include that it is inherently multienergy, expands material decomposition capabilities, and improves spatial resolution and geometric quantification. Further, the utility of virtual monoenergetic images to standardize CT numbers is discussed, as virtual monoenergetic images can be the default image type in PCD-CT due to the full-time spectral nature of the technology.

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Section: Musculoskeletal Anatomymentioning

confidence: 88%

Standardization and Quantitative Imaging With Photon-Counting Detector CT

2023

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“…The number of studies investigating the visibility of the interface between bone and implant material is limited. Lau et al [ 29 ] found that polyethylene insert wear and metallic tibial tray wear could be detected by multi-energy PCD-CT. Other studies have shown improved visibility of bone structures in the wrist [ 13 , 30 ], the shoulder and the pelvis [ 16 ]. The PCD-CT system in our study uses additional tin filtration and an extended Hounsfield scale, reducing the magnitude of metal artefacts [ 31 ].…”

Section: Discussionmentioning

confidence: 99%

Improved visualization of the bone-implant interface and osseointegration in ex vivo acetabular cup implants using photon-counting detector CT

et al. 2023

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Background Successful osseointegration of joint replacement implants is required for long-term implant survival. Accurate assessment of osseointegration could enable clinical discrimination of failed implants from other sources of pain avoiding unnecessary surgeries. Photon-counting detector computed tomography (PCD-CT) provides improvements in image resolution compared to conventional energy-integrating detector CT (EID-CT), possibly allowing better visualization of bone-implant-interfaces and osseointegration. The aim of this study was to assess the quality of visualization of bone-implant-interfaces and osseointegration in acetabular cup implants, using PCD-CT compared with EID-CT. Methods Two acetabular implants (one cemented, one uncemented) retrieved during revision surgery were scanned using PCD-CT and EID-CT at equal radiation dose. Images were reconstructed using different reconstruction kernels and iterative strengths. Delineation of the bone-implant and bone-cement-interface as an indicator of osseointegration was scored subjectively for image quality by four radiologists on a Likert scale and assessed quantitatively. Results Delineation of bone-implant and bone-cement-interfaces was better with PCD-CT compared with EID-CT (p ≤ 0.030). The highest ratings were given for PCD-CT at sharper kernels for the cemented cup (PCD-CT, median 5, interquartile range 4.25–5.00 versus EID-CT, 3, 2.00–3.75, p < 0.001) and the uncemented cup (5, 4.00–5.00 versus 2, 2–2, respectively, p < 0.001). The bone-implant-interface was 35–42% sharper and the bone-cement-interface was 28–43% sharper with PCD-CT compared with EID-CT, depending on the reconstruction kernel. Conclusions PCD-CT might enable a more accurate assessment of osseointegration of orthopedic joint replacement implants. Key points • The bone-implant interface ex vivo showed superior visualization using photon-counting detector computed tomography (PCD-CT) compared to energy-integrating detector computed tomography. • Harder reconstruction kernels in PCD-CT provide sharper images with lower noise levels. • These improvements in imaging might make it possible to visualize osseointegration in vivo.

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“…The SPCCT prototype used in the present study is based on a clinical CT scanner and displayed all its characteristics with the potential to be used in a short period of time in clinics. Performances were already tested in living patients for brain, lung, heart, and to describe the anatomy of temporal bone and wrist [11][12][13][14][15][16][17], but never for osteo-articular diseases. Our results suggest that SPCCT has the potential to provide biomarkers for OA characterization for both cartilage, and bone.…”

Section: Discussionmentioning

confidence: 99%

“…They are characterized by new detectors, i.e., energy-resolving photon-counting detector, that simultaneously count photons and resolve their energy [10]. In living patients, SPCCT has, for instance, been already used to characterize kidney stones [11], coronary artery calcium scoring [12], coronary stent [13], lung cancers [14], brain [15] and anatomical structures of temporal bone and wrist [16,17]. SPCCT extends the dual energy CT approach by a multispectral approach [18].…”

Section: Introductionmentioning

confidence: 99%

Quantification of cartilage and subchondral bone cysts on knee specimens based on a spectral photon-counting computed tomography

Garcelon

Abascal

Olivier

et al. 2022

Preprint

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Spectral Photon-Counting Computed Tomography (SPCCT) is a new technique with the capability to provide mono-energetic (monoE) images with high signal to noise ratio. We demonstrate the feasibility of SPCCT to characterize at the same time cartilage and subchondral bone cysts (SBCs) without contrast agent in osteoarthritis (OA). To achieve this goal, 5 human knee specimens (3 normal and 2 with OA) were imaged with a clinical prototype SPCCT. The monoE images at 60 keV with isotropic voxels of 250x250x250 µm3 were compared with monoE synchrotron radiation CT (SR CT) images at 55 keV with isotropic voxels of 45x45x45 µm3 used as benchmark for cartilage segmentation. The volume and density of SBCs were evaluated in the two OA knees in SPCCT images. In 25 compartments (tibial lateral, tibial medial, femoral lateral, femoral medial and patella), the mean bias between SPCCT and SR CT analyses were 106 ± 196mm3 for cartilage volume and − 0.006mm ± 0.06 for mean cartilage thickness. The 2 OA knees displayed different SBCs profiles in terms of volume, density, and distribution according to size and location. SPCCT with fast acquisitions is able to characterize cartilage morphology and SBCs. SPCCT can be used potentially as a new tool in clinical studies in OA.

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Improved visualization of the wrist at lower radiation dose with photon-counting-detector CT

Cited by 45 publications

References 23 publications

Standardization and Quantitative Imaging With Photon-Counting Detector CT

Standardization and Quantitative Imaging With Photon-Counting Detector CT

Improved visualization of the bone-implant interface and osseointegration in ex vivo acetabular cup implants using photon-counting detector CT

Quantification of cartilage and subchondral bone cysts on knee specimens based on a spectral photon-counting computed tomography

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