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Objective: To determine the number of imaging examinations, radiation dose and the time to complete traunia-related imaging in multiple trauma patients before and after introduction of whole-body CT (WBCT) into early trauma care. Methods: 120 consecutive patients before and 120 patients after introduction of WBCT into the trauma algorithm of the University Hospital Zurich were compared regarding the number and type of CT, radiography, focused assessment with sonography for trauma (FAST), additional CT examinations (defined as CT of the same body regions after radiography and/or FAST) and the time to complete trauma-related imaging. Results: In the WBCT cohort, significantly more patients underwent CT of the head. neck, chest and abdomen (p < 0.001) than in the non-WBCT cohort, whereas the number of radiographic examinations of the cervical spine, chest and pelvis and of FAST examinations were significantly lower (p< 0.001). There were no significant differences between cohorts regarding the number of radiographic examinations of the upper (p = 0.56) and lower extremities (p = 0.30). We found significantly higher effective doses in the WBCT (29.5 rnSv) than in the non-WBCT cohort (15.9 mSv: p< 0.001), but fewer additional CT examinations for completing the work-up were needed m the WBCT cohort (p< 0.001). The time to complete trauma-related imaging was significantly shorter in the WBCT (12min) than in the non-WBCT cohort (75min; p< 0.001). Conclusion: Including WBCT in the initial work-up of trauma patients results in higher radiation doses, but fewer additional CT examinations are needed, and the time for completing trauma-related imaging is shorter. Advances in knowledge: WBCT tn trauma patients is associated with a high radiation dose of 29.5 mSv. [ABSTRACT FROM AUTHOR]

Objective: This study assessed the potential of ultra-high resolution (UHR) and a 1024-matrix in photon-counting-detector CT (PCD-CT) for evaluating interstitial lung disease (ILD) in systemic sclerosis (SSc) patients., Methods: Sixty-six SSc patients who underwent ILD-CT screening on a first-generation PCD-CT were retrospectively included. Scans were performed in UHR mode at 100 kVp with two different matrix sizes (512×512 and 1024x1024) and reconstructed at slice thicknesses of 1.5 and 0.2 mm. Image noise, subjective image quality, and ILD changes (ground glass opacities and reticulations) were evaluated on a 5-point Likert-scale by two independent readers., Results: Interreader agreement for subjective image quality ranged from fair to almost perfect (Krippendorff-Alpha: 0.258-0.862). Overall image quality was highest for 1.5 mm/1024 matrix images [(reader 1: 4(4.4), reader 2: 5(4.5)]. Image sharpness was rated significantly better in 0.2 mm images (P < .001). Regarding ILD changes, 0.2 mm slice thickness outperformed 1.5 mm slice thickness significantly (P < .001), while there was no significant difference between the two matrix sizes. A 1024-matrix size demonstrated superiority in evaluating coarse reticulations compared to 512-matrix size., Conclusion: UHR mode with a 0.2 mm slice thickness showed enhanced image sharpness and improved visibility of ILD changes compared to standard reconstructions. This has the potential to enable the early detection of subtle disease manifestations., Advances in Knowledge: With the invention of PCD-CT different reconstruction algorithms need to be evaluated for specific pathologies. In our study ILD UHR mode with 0.2 mm slice thickness showed to be beneficial in the detection of parenchymal changes in patients with scleroderma., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology.)

Objective: To evaluate the performance of virtual non-contrast images (VNC) compared to true non-contrast (TNC) images in photon-counting detector computed tomography (PCD-CT) for the evaluation of lung parenchyma and emphysema quantification., Methods: 65 (mean age 73 years; 48 male) consecutive patients who underwent a three-phase (non-contrast, arterial and venous) chest/abdomen CT on a first-generation dual-source PCD-CT were retrospectively included. Scans were performed in the multienergy (QuantumPlus) mode at 120 kV with 70 ml intravenous contrast agent at an injection rate of 4 ml s -1 . VNC were reconstructed from the arterial (VNC art ) and venous phase (VNC ven ). TNC and VNC images of the lung were assessed quantitatively by calculating the global noise index (GNI) and qualitatively by two independent, blinded readers (overall image quality and emphysema assessment). Emphysema quantification was performed using a commercially available software tool at a threshold of -950 HU for all data sets. TNC images served as reference standard for emphysema quantification. Low attenuation values (LAV) were compared in a Bland-Altman plot., Results: GNI was similar in VNC art (103.0 ± 30.1) and VNC ven (98.2 ± 22.2) as compared to TNC (100.9 ± 19.0, p = 0.546 and p = 0.272, respectively). Subjective image quality (emphysema assessment and overall image quality) was highest for TNC ( p = 0.001), followed by VNC ven and VNC art . Both, VNC art and VNC ven showed no significant difference in emphysema quantification as compared to TNC ( p = 0.409 vs. p = 0.093; respectively)., Conclusion: Emphysema evaluation is feasible using virtual non-contrast images from PCD-CT., Advances in Knowledge: Emphysema quantification is feasible and accurate using VNC images in PCD-CT. Based on these findings, additional TNC scans for emphysema quantification could be omitted in the future.

Objectives: In this study, we aimed to assess the impact of different CT reconstruction kernels on the stability of radiomic features and the transferability between different diseases and tissue types. Three lung diseases were evaluated, i.e . non-small cell lung cancer (NSCLC), malignant pleural mesothelioma (MPM) and interstitial lung disease related to systemic sclerosis (SSc-ILD) as well as four different tissue types, i.e . primary tumor, largest involved lymph node ipsilateral and contralateral lung., Methods: Pre-treatment non-contrast enhanced CT scans from 23 NSCLC, 10 MPM and 12 SSc-ILD patients were collected retrospectively. For each patient, CT scans were reconstructed using smooth and sharp kernel in filtered back projection. The regions of interest (ROIs) were contoured on the smooth kernel-based CT and transferred to the sharp kernel-based CT. The voxels were resized to the largest voxel dimension of each cohort. In total, 1386 features were analyzed. Feature stability was assessed using the intraclass correlation coefficient. Features above the stability threshold >0.9 were considered stable., Results: We observed a strong impact of the reconstruction method on stability of the features (at maximum 26% of the 1386 features were stable). Intensity features were the most stable followed by texture and wavelet features. The wavelet features showed a positive correlation between percentage of stable features and size of the ROI (R2 = 0.79, p = 0.005). Lymph node radiomics showed poorest stability (<10%) and lung radiomics the largest stability (26%). Robustness analysis done on the contralateral lung could to a large extent be transferred to the ipsilateral lung, and the overlap of stable lung features between different lung diseases was more than 50%. However, results of robustness studies cannot be transferred between tissue types, which was investigated in NSCLC and MPM patients; the overlap of stable features for lymph node and lung, as well as for primary tumor and lymph node was very small in both disease types., Conclusion: The robustness of radiomic features is strongly affected by different reconstruction kernels. The effect is largely influenced by the tissue type and less by the disease type., Advances in Knowledge: The study presents to our knowledge the most complete analysis on the impact of convolution kernel on the robustness of CT-based radiomics for four relevant tissue types in three different lung diseases. .

Objective: The purpose of this study was to compare the diagnostic accuracy of positron emission tomography (PET)/MRI with PET/CT for determining tumor resectability of non-small cell lung cancer (NSCLC)., Methods: Sequential trimodality PET/CT/MRI was performed in 36 patients referred with the clinical question of resectability assessment in NSCLC. PET/CT and PET/MR images including T 1 weighted sequence ( T 1 -Dixon) and respiration gated T 2 weighted sequence ( T 2 -Propeller) were evaluated for resectability-defining factors; i.e. longest diameter of the tumor, minimal tumor distance to the carina, mediastinal invasion, invasion of the carina, pleural infiltration, pericardial infiltration, diaphragm infiltration, presence of additional nodules., Results: There was no significant difference of maximal axial diameter measurements of the primary lung tumors and narrow limits of agreement in Bland-Altman analysis ranging from -11.1  mm to + 11.8  mm for T 2 -Propeller and from -14.3  mm to + 13.8  mm for T 1 -Dixon sequence. A high agreement of PET/MR with PET/CT for the different resectability-defining factors was observed ( k from 0.769 to 1.000). There was an excellent agreement of T 2 -Propeller sequence and CT for additional pulmonary nodule detection ( k of 0.829 and 0.833), but only a moderate and good agreement using T 1 -Dixon sequence ( k of 0.484 and 0.722)., Conclusion: In NSCLC the use of PET/MRI, including a dedicated pulmonary MR imaging protocol, provides a comparable diagnostic value for determination of tumor resectability compared to PET/CT., Advances in Knowledge: Our findings suggest that whole body PET/MRI can safely be used for the local staging of NSCLC patients. Further studies are warranted to determine whether it is feasible to integrate an imaging sequence in a whole body PET/MRI setting with the potential advantage of detection of liver or brain metastases., Competing Interests: Conflict of interestPatrick Veit-Haibach received investigator-initiated study grants from Bayer Healthcare, GE Healthcare and Roche Pharmaceuticals, and speaker fees from GE Healthcare. Gaspar Delso is an employee of GE Healthcare. Martin Huellner received speaker’s fees from GE Healthcare. The other authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. There was financial support for this study from GE Healthcare on an institutional level. Only non-GE Healthcare employees had control of inclusion of the data and information that might present a conflict of interest for those authors who are employees of GE Healthcare.

Objectives: To investigate the diagnostic performance of advanced modelled iterative reconstruction (ADMIRE) to filtered back projection (FBP) when using an ultralow-dose protocol for the detection of solid and subsolid pulmonary nodules., Methods: Single-energy CT was performed at 100 kVp with tin filtration in an anthropomorphic chest phantom with solid and subsolid pulmonary nodules (2-10 mm, attenuation, 20 to -800 HU at 120 kVp). The mean volume CT dose index (CTDIvol) of the standard chest protocol was 2.2 mGy. Subsequent scans were obtained at 1/8 (0.28 mGy), 1/20 (0.10 mGy) and 1/70 (0.03 mGy) dose levels by lowering tube voltage and tube current. Images were reconstructed with FBP and ADMIRE. One reader measured image noise; two readers determined image quality and assessed nodule localization., Results: Image noise was significantly reduced using ADMIRE compared with FBP (ADMIRE at a strength level of 5 : 70.4% for 1/20; 71.6% for 1/8; p < 0.001). Interobserver agreement for image quality was excellent (k = 0.88). Image quality was considered diagnostic for all images at 1/20 dose using ADMIRE. Sensitivity of nodule detection was 97.1% (100% for solid, 93.8% for subsolid nodules) at 1/20 dose and 100% for both nodule entities at 1/8 dose using ADMIRE 5. Images obtained with 1/70 dose had moderate sensitivity (overall 85.7%; solid 95%; subsolid 73.3%)., Conclusion: Our study suggests that with a combination of tin filtration and ADMIRE, the CTDIvol of chest CT can be lowered considerably, while sensitivity for nodule detection remains high. For solid nodules, CTDIvol was 0.10 mGy, while subsolid nodules required a slightly higher CTDIvol of 0.28 mGy., Advances in Knowledge: Detection of subsolid nodules is feasible with ultralow-dose protocols.