Search

This study aimed to identify predictive (bio-)markers for COVID-19 severity derived from automated quantitative thin slice low dose volumetric CT analysis, clinical chemistry and lung function testing. Seventy-four COVID-19 patients admitted between March 16th and June 3rd 2020 to the Asklepios Lung Clinic Munich-Gauting, Germany, were included in the study. Patients were categorized in a non-severe group including patients hospitalized on general wards only and in a severe group including patients requiring intensive care treatment. Fully automated quantification of CT scans was performed via IMBIO CT Lung Texture analysis™ software. Predictive biomarkers were assessed with receiver-operator-curve and likelihood analysis. Fifty-five patients (44% female) presented with non-severe COVID-19 and 19 patients (32% female) with severe disease. Five fatalities were reported in the severe group. Accurate automated CT analysis was possible with 61 CTs (82%). Disease severity was linked to lower residual normal lung (72.5% vs 87%, p = 0.003), increased ground glass opacities (GGO) (8% vs 5%, p = 0.031) and increased reticular pattern (8% vs 2%, p = 0.025). Disease severity was associated with advanced age (76 vs 59 years, p = 0.001) and elevated serum C-reactive protein (CRP, 92.2 vs 36.3 mg/L, p < 0.001), lactate dehydrogenase (LDH, 485 vs 268 IU/L, p < 0.001) and oxygen supplementation (p < 0.001) upon admission. Predictive risk factors for the development of severe COVID-19 were oxygen supplementation, LDH >313 IU/L, CRP >71 mg/L, <70% normal lung texture, >12.5% GGO and >4.5% reticular pattern. Automated low dose CT analysis upon admission might be a useful tool to predict COVID-19 severity in patients. • Automated quantitative thin slice volumetric low dose CT analysis could be a useful tool for prediction of COVID-19 severity on admission. • Need for oxygen supplementation, LDH >313 IU/L and CRP >71 mg/L were identified as clinical markers predicting disease severity. • Normal lung texture <70%, GGO >12.5% and reticular pattern >4.5% in CT were indicative of severe disease. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate possible use for cone‐beam computed tomography (CBCT) guidance, this phantom study evaluated the contrast enhancement provided by Gadoxetate Disodium (Primovist® CAN/EU, or Eovist® USA, Bayer Healthcare, Leverkusen, Germany), a contrast agent that is taken up selectively by liver cells and is retained for up to an hour. Image quality from CBCT was benchmarked against helical fan‐beam computed tomography for two phantom geometries. Methods and Materials: Concentrations were diluted to 0.0125–0.1 mmol per kilogram of body weight (mmol/kg) corresponding to expected physiological concentrations in the liver. Kilovoltage CBCT imaging parameters of x‐ray tube potential, current, and filtration were investigated using clinically available options on a TrueBeam STx linear accelerator CBCT platform. Two phantoms were created, a cylindrical idealized imaging geometry and an ellipsoidal more realistic abdominal geometry. All parameters were optimized according to the contrast‐to‐noise ratio (CNR) image quality metric, as a function of concentration, following the Rose criterion for CNR. Results: Acceptable CNR was defined as greater than or equal to three, in accordance with the Rose criterion for CNR. These were found in a range of expected liver concentrations of 0.025–0.1 mmol/kg for a tube potential of 100 kVp, half‐fan bowtie filtration and tube currents giving exposures between 2025 and 5085 mAs. Linear correlations were found for all CNR as a function of concentration, in agreement with the literature. Conclusion: Based on this phantom study, with appropriate selection of imaging protocol, Gadoxetate Disodium may provide useful liver CBCT enhancement at physiologically achievable liver concentrations. [ABSTRACT FROM AUTHOR]

The accuracy of coronary calcium scoring using 16-row MSCT comparing 1- and 3-mm slices was assessed. A thorax phantom with calcium cylinder inserts was scanned applying a non-enhanced retrospectively ECG-gated examination protocol: collimation 12 x 0.75 mm; 120 kV; 133 mAs(eff). Thirty-eight patients were examined using the same scan protocol. Image reconstruction was performed with an effective slice thickness of 3 and 1 mm. The volume score, calcium mass and Agatston score were determined. Image noise was measured in both studies. The volume score and calcium mass varied less than the Agatston score. The overall measured calcium mass compared to the actual calcium mass revealed a relative difference of +2.0% for 1-mm slices and -1.2% for 3-mm slices. Due to increased image noise in thinner slices in the patient study (26.1 HU), overall calcium scoring with a scoring threshold of 130 HU was not feasible. Interlesion comparison showed significantly higher scoring results for thinner slices (all P<0.001). A similar accuracy comparing calcium scoring results of 1- and 3-mm slices was shown in the phantom study; therefore, the potentially necessary increase of the patient's dose in order to achieve assessable 1-mm slices with an acceptable image-to-noise-ratio appears not to be justified. [ABSTRACT FROM AUTHOR]

Multi-slice (MS) technology increases the efficacy of CT procedures and offers new promising applications. The expanding use of MSCT, however, may result in an increase in both frequency of procedures and levels of patient exposure. It was, therefore, the aim of this study to gain an overview of MSCT examinations conducted in Germany in 2001. All MSCT facilities were requested to provide information about 14 standard examinations with respect to scan parameters and frequency. Based on this data, dosimetric quantities were estimated using an experimentally validated formalism. Results are compared with those of a previous survey for single-slice (SS) spiral CT scanners. According to the data provided for 39 dual- and 73 quad-slice systems, the average annual number of patients examined at MSCT is markedly higher than that examined at SSCT scanners (5500 vs 3500). The average effective dose to patients was changed from 7.4 mSv at single-slice to 5.5 mSv and 8.1 mSv at dual- and quad-slice scanners, respectively. There is a considerable potential for dose reduction at quad-slice systems by an optimisation of scan protocols and better education of the personnel. To avoid an increase in the collective effective dose from CT procedures, a clear medical justification is required in each case. [ABSTRACT FROM AUTHOR]

Objective: To compare the sensitivity and specificity of unenhanced spiral computed tomography (CT) and ultrasonography (US) in patients with suspected acute appendicitis. Design: Prospective study. Setting: University hospital, Germany. Subjects: 120 consecutive patients with acute appendicitis as a differential diagnosis, whose clinical findings were not enough to make operation essential, but were too severe to send home. Interventions: CT and US of the appendix. Main outcome measures: Sensitivity, specificity, and positive and negative predictive value. Results: The results were correlated with surgical and histopathological findings at appendicectomy or clinical follow-up. 93 patients had acute appendicitis, 27 patients did not. The sensitivity of CT was 95% and of US 87%. The corresponding specificities were 89% and 74%, positive predictive values 97% and 92%, negative predictive values 83% and 63%. In the 27 patients who did not have acute appendicitis, the correct diagnosis was established with CT in 14 patients and with US in eight. Conclusion: CT is more sensitive and specific than US in patients suspected of having acute appendicitis, but in whom the presentation is equivocal. The use of unenhanced spiral CT led to a significant improvement in the accuracy of preoperative diagnosis and a lower negative appendicectomy rate. [ABSTRACT FROM AUTHOR]