TY  - JOUR
A1  - Patzer, Theresa Sophie
A1  - Kunz, Andreas Steven
A1  - Huflage, Henner
A1  - Conrads, Nora
A1  - Luetkens, Karsten Sebastian
A1  - Pannenbecker, Pauline
A1  - Paul, Mila Marie
A1  - Ergün, Süleyman
A1  - Bley, Thorsten Alexander
A1  - Grunz, Jan-Peter
T1  - Ultrahigh-resolution photon-counting CT in cadaveric fracture models: spatial frequency is not everything
JF  - Diagnostics
N2  - In this study, the impact of reconstruction sharpness on the visualization of the appendicular skeleton in ultrahigh-resolution (UHR) photon-counting detector (PCD) CT was investigated. Sixteen cadaveric extremities (eight fractured) were examined with a standardized 120 kVp scan protocol (CTDI\(_{vol}\) 10 mGy). Images were reconstructed with the sharpest non-UHR kernel (Br76) and all available UHR kernels (Br80 to Br96). Seven radiologists evaluated image quality and fracture assessability. Interrater agreement was assessed with the intraclass correlation coefficient. For quantitative comparisons, signal-to-noise-ratios (SNRs) were calculated. Subjective image quality was best for Br84 (median 1, interquartile range 1–3; p ≤ 0.003). Regarding fracture assessability, no significant difference was ascertained between Br76, Br80 and Br84 (p > 0.999), with inferior ratings for all sharper kernels (p < 0.001). Interrater agreement for image quality (0.795, 0.732–0.848; p < 0.001) and fracture assessability (0.880; 0.842–0.911; p < 0.001) was good. SNR was highest for Br76 (3.4, 3.0–3.9) with no significant difference to Br80 and Br84 (p > 0.999). Br76 and Br80 produced higher SNRs than all kernels sharper than Br84 (p ≤ 0.026). In conclusion, PCD-CT reconstructions with a moderate UHR kernel offer superior image quality for visualizing the appendicular skeleton. Fracture assessability benefits from sharp non-UHR and moderate UHR kernels, while ultra-sharp reconstructions incur augmented image noise.
KW  - photon-counting
KW  - tomography
KW  - X-ray computed
KW  - fracture
KW  - cancellous bone
KW  - convolution kernel
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-319281
SN  - 2075-4418
VL  - 13
IS  - 10
ER  - 
TY  - JOUR
A1  - Luetkens, Karsten Sebastian
A1  - Ergün, Süleyman
A1  - Huflage, Henner
A1  - Kunz, Andreas Steven
A1  - Gietzen, Carsten Herbert
A1  - Conrads, Nora
A1  - Pennig, Lenhard
A1  - Goertz, Lukas
A1  - Bley, Thorsten Alexander
A1  - Gassenmaier, Tobias
A1  - Grunz, Jan-Peter
T1  - Dose reduction potential in cone-beam CT imaging of upper extremity joints with a twin robotic x-ray system
JF  - Scientific Reports
N2  - Cone-beam computed tomography is a powerful tool for 3D imaging of the appendicular skeleton, facilitating detailed visualization of bone microarchitecture. This study evaluated various combinations of acquisition and reconstruction parameters for the cone-beam CT mode of a twin robotic x-ray system in cadaveric wrist and elbow scans, aiming to define the best possible trade-off between image quality and radiation dose. Images were acquired with different combinations of tube voltage and tube current–time product, resulting in five scan protocols with varying volume CT dose indices: full-dose (FD; 17.4 mGy), low-dose (LD; 4.5 mGy), ultra-low-dose (ULD; 1.15 mGy), modulated low-dose (mLD; 0.6 mGy) and modulated ultra-low-dose (mULD; 0.29 mGy). Each set of projection data was reconstructed with three convolution kernels (very sharp [Ur77], sharp [Br69], intermediate [Br62]). Five radiologists subjectively assessed the image quality of cortical bone, cancellous bone and soft tissue using seven-point scales. Irrespective of the reconstruction kernel, overall image quality of every FD, LD and ULD scan was deemed suitable for diagnostic use in contrast to mLD (very sharp/sharp/intermediate: 60/55/70%) and mULD (0/3/5%). Superior depiction of cortical and cancellous bone was achieved in FD\(_{Ur77}\) and LD\(_{Ur77}\) examinations (p < 0.001) with LD\(_{Ur77}\) scans also providing favorable bone visualization compared to FD\(_{Br69}\) and FD\(_{Br62}\) (p < 0.001). Fleiss’ kappa was 0.618 (0.594–0.641; p < 0.001), indicating substantial interrater reliability. In this study, we demonstrate that considerable dose reduction can be realized while maintaining diagnostic image quality in upper extremity joint scans with the cone-beam CT mode of a twin robotic x-ray system. Application of sharper convolution kernels for image reconstruction facilitates superior display of bone microarchitecture.
KW  - medical research
KW  - preclinical research
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270429
VL  - 11
IS  - 1
ER  -