Optimization of Postprocessing parameters for abdominal Forensic CT scans.

Aim: Postmortem Computed Tomography (PMCT) is gradually introduced at forensic institutes. Image reconstruction software can increase diagnostic potential in CT by increasing distinction between structures and reduction of artifacts. The aim of this study was to develop and evaluate novel image reconstruction parameters for postmortem conditions, to increase image quality and diagnostic potential of CT scans. Method: Twenty PMCT scans of deceased hereof two in severe decay were subjected to four reconstruction techniques: a standard reconstruction algorithm, the detail reconstruction algorithm and two novel algorithms based on the standard algorithm, but with different Hounsfield settings. Image quality was evaluated by visual grading analysis (VGA) by four forensic radiologist observers. Results: The VGA did not prove that any of the reconstruction techniques were superior to the others. For standard and detail, the two pre-defined reconstruction algorithms, VGA scores were indiscernible and were superior to the equally indiscernible Hounsfield reconstructions on parameters translated into Sharpness and Low Contrast Resolution. The two alternative Hounsfield settings were superior with respect to Noise and Artifacts/Beam Hardening. Conclusion: The study elucidates the possiblity for multiple reconstructions specialized for PMCT conditions, to accommodate the special conditions when working with the deceased. Despite the lack of clear improvements in the tested reconstructions, this study provides an insight into some of the possibilities of improving PMCT quality using reconstruction techniques.

Ultra-low dose computed tomography of the chest in an emergency setting: A prospective agreement study.

Ultra-low dose computed tomography (ULD-CT) assessed by non-radiologists in a medical Emergency Department (ED) has not been examined in previous studies. To (i) investigate intragroup agreement among attending physicians caring for ED patients (i.e., radiologists, senior- and junior clinicians) and medical students for the detection of acute lung conditions on ULD-CT and supine chest X-ray (sCXR), and (ii) evaluate the accuracy of interpretation compared to the reference standard. In this prospective study, non-traumatic patients presenting to the ED, who received an sCXR were included. Between February and July 2019, 91 patients who underwent 93 consecutive examinations were enrolled. Subsequently, a ULD-CT and non-contrast CT were performed. The ULD-CT and sCXR were assessed by 3 radiologists, 3 senior clinicians, 3 junior clinicians, and 3 medical students for pneumonia, pneumothorax, pleural effusion, and pulmonary edema. The non-contrast CT, assessed by a chest radiologist, was used as the reference standard. The results of the assessments were compared within each group (intragroup agreement) and with the reference standard (accuracy) using kappa statistics. Accuracy and intragroup agreement improved for pneumothorax on ULD-CT compared with the sCXR for all groups. Accuracy and intragroup agreement improved for pneumonia on ULD-CT when assessed by radiologists and for pleural effusion when assessed by medical students. In patients with acute lung conditions ULD-CT offers improvement in the detection of pneumonia by radiologists and the detection of pneumothorax by radiologists as well as non-radiologists compared to sCXR. Therefore, ULD-CT may be considered as an alternative first-line imaging modality to sCXR for non-traumatic patients who present to EDs.

Diagnostic accuracy of ultra-low-dose chest computed tomography in an emergency department.

BACKGROUND: This study examined whether ultra-low-dose chest computed tomography (ULD-CT) could improve detection of acute chest conditions. PURPOSE: To determine (i) whether diagnostic accuracy of ULD-CT is superior to supine chest X-ray (sCXR) for acute chest conditions and (ii) the feasibility of ULD-CT in an emergency department. MATERIAL AND METHODS: From 1 February to 31 July 2019, 91 non-traumatic patients from the Emergency Department were prospectively enrolled in the study if they received an sCXR. An ULD-CT and a non-contrast chest CT (NCCT) scan were then performed. Three radiologists assessed the sCXR and ULD-CT examinations for cardiogenic pulmonary edema, pneumonia, pneumothorax, and pleural effusion. Resources and effort were compared for sCXR and ULD-CT to evaluate feasibility. Diagnostic accuracy was calculated for sCXR and ULD-CT using NCCT as the reference standard. RESULTS: The mean effective dose of ULD-CT was 0.05±0.01 mSv. For pleural effusion and cardiogenic pulmonary edema, no difference in diagnostic accuracy between ULD-CT and sCXR was observed. For pneumonia and pneumothorax, sensitivities were 100% (95% confidence interval [CI] 69-100) and 50% (95% CI 7-93) for ULD-CT and 60% (95% CI 26-88) and 0% (95% CI 0-0) for sCXR, respectively. Median examination time was 10 min for ULD-CT vs. 5 min for sCXR (P<0.001). For ULD-CT 1-2 more staff members were needed compared to sCXR (P<0.001). ULD-CT was rated more challenging to perform than sCXR (P<0.001). CONCLUSION: ULD-CT seems equal or better in detecting acute chest conditions compared to sCXR. However, ULD-CT examinations demand more effort and resources.