This study evaluates ultra-low-dose computed tomography (ULDCT) protocols concerning the detectability of pulmonary nodules. The influence of tube current settings, kernels, strength levels of third-generation iterative reconstruction algorithms, and pitch was investigated. A chest phantom with artificial spherical nodules of different densities and diameters was examined with a third-generation dual-source CT. Scanning and post-processing protocols, tube current levels, and ultra-high and non-high pitch modes were applied. Images were reconstructed with filtered back-projection (FBP) or advanced model-based iterative reconstruction (ADMIRE) algorithms. Sharp (Bl57) or medium-soft (Br36) convolution kernels were applied. The reading was performed by an experienced and an inexperienced reader. The highest observer sensitivity was found using a non-high pitch protocol at tube currents of 120 mAs and 90 mAs with the sharp kernel and iterative reconstruction level of 5. Non-high pitch protocols showed better detectability of solid nodules. Combinations with the medium-soft kernel achieved slightly higher observer sensitivity than with the sharp kernel. False positives (FP) occurred more often for subsolid nodules, at a tube current level of 120 mAs, and with the sharp kernel. A tube current level of 90 mAs combined with the highest iterative reconstruction level achieved the highest accuracy in lung nodule detection regardless of size, density, and reader experience.

Background The paramedian forehead flap is an axial pattern flap with frequent use in plastic reconstruction of complex nasal defects. Its main blood supply is based on the supratrochlear artery as part of the supraorbital/nasal plexus.

Objectives To investigate the effect of a device-assisted suction against resistance Mueller maneuver (MM) on transient interruption of contrast (TIC) in the aorta and pulmonary trunk (PT) on computed tomography pulmonary angiogram (CTPA). Methods In this prospective single-center study, 150 patients with suspected pulmonary artery embolism were assigned randomly with two different breathing maneuvers (Mueller maneuver (MM) or standard end-inspiratory breath-hold command (SBC)) during routine CTPA. The MM was performed using a patented prototype (Contrast Booster™) which allows both the patient by means of visual feedback and the medical staff in the CT scanning room to monitor whether the patient is sucking sufficiently or not. Mean Hounsfield attenuation in descending aorta and PT was measured and compared. Results Overall, patients with MM showed an attenuation of 338.24 HU in the pulmonary trunk, compared to 313.71 HU in SBC ( p = 0.157). In the aorta, the values for MM were lower compared to SBC (134.42 HU vs. 177.83 HU, p = 0.001). The TP-aortic ratio was significantly higher in the MM group at 3.86 compared to the SBC group at 2.26, p = 0.001. TIC phenomenon was absent in the MM group, whereas it was present in 9 patients (12.3%) in the SBC group ( p = 0.005). Overall contrast was better on all levels for MM ( p < 0.001). The presence of breathing artifacts was higher in the MM group (48.1% vs. 30.1%, p = 0.038), without clinical consequence. Conclusions Performing the MM with the application of the prototype is an effective way of preventing the TIC phenomenon during i.v. contrast-enhanced CTPA scanning compared to the standard end-inspiratory breathing command. Clinical relevance Compared to standard end-inspiratory breathing command, the device-assisted Mueller maneuver (MM) improves contrast enhancement and prevents the transient interruption of contrast (TIC) phenomenon in CTPA. Therefore, it may offer optimized diagnostic workup and timely treatment for patients with pulmonary embolism. Key Points • Transient interruption of contrast (TIC) may impair image quality in CTPA. • Mueller Maneuver using a device prototype could lower the rate of TIC. • Device application in clinical routine may increase diagnostic accuracy.

Einleitung Zur plastischen Rekonstruktion komplexer Nasendefekte wird oft der axial gestielte paramediane Stirnlappen eingesetzt. Die Blutversorgung erfolgt primär über die A. supratrochlearis, die zum supraorbitalen Gefäßplexus gehört.

The aim was to prospectively evaluate the diagnostic and prognostic value of different quantitative analysis methods assessing adrenal gland parameters on contrast-enhanced CT scans in patients with septic conditions. Seventy–six patients (49 men, 27 women) received CT scans for focus search. Adrenal glands were analyzed by means of three different methods: subjective region of interest (ROI) measurement, organ segmentation and histogram analysis using semi-automated software. Univariate analyses with multiple testing thresholds and receiver operating characteristic curves were performed. Clinical endpoints were 8-days, 28-days and 6-months mortality. Forty-four CT scans were analyzed (ground truth: patients with no sepsis: n = 6; patients with sepsis: n = 15; patients in septic shock: n = 21). Left adrenal gland (LAG) values were analyzed and compared, as data variation was lower than in the right adrenal glands. In patients with septic conditions, the combination of high LAG and Inferior Vena Cava (IVC) density values was highly specific for septic shock with all three methods. Only segmentation values were significantly different between the sepsis and septic shock groups after confounder correction (p = 0.048). Total adrenal gland volume was 20% higher in the septic shock patients while a relatively small LAG volume within the septic shock subgroup was associated with higher mortality at day 8 (AUC = 0.8; p = 0.006) and at 6 months (AUC = 0.7; p = 0.035). However, time-consuming density analysis methods assessing adrenal glands do not provide additional diagnostic value in patients with septic conditions. The combination of high LAG and IVC attenuation values seems to be highly specific for septic shock, regardless of the analysis type. Adrenal gland volume reveals short- and long-term prognostic capacity.

Purpose: Previous studies have shown positive effects of intensive low-density lipoprotein (LDL)-lowering therapy on atheroma volume using invasive intravascular ultrasound. This study describes the changes in coronary plaque composition on coronary computed tomography angiography in patients treated with proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors. Materials and Methods: In this prospective study, coronary plaques were analyzed using third-generation dual-source computed tomography before and after 1 year of PCSK9-inhibitor treatment. Plaque markers included total plaque volume (TPV), calcified plaque volume (CPV), noncalcified plaque volume (NCPV), lumen volume and vessel volume (VV), minimal luminal area (MLA), minimal lumen diameter (MLD), corrected coronary opacification, eccentricity, remodeling index, and functional plaque parameters. Primary endpoint was defined as change in TPV; the secondary endpoint was TPV or CPV regression or nominal change in plaque parameters. Results: We analyzed 74 coronary plaques in 23 patients (60±9 y, 65% male). After 1 year of PCSK9-inhibitor treatment, LDL was reduced from 148 to 66 mg/dL (P<0.0001). Significant changes were found for VV (196 to 215 mm3, P=0.0340), MLA (3.1 to 2.6 mm2, P=0.0413), and MLD (1.7 to 1.4 mm, P=0.0048). TPV, CPV, NCPV, lumen volume, and functional plaque parameters did not change significantly (P>0.05). Conclusions: Coronary artery plaque analysis by coronary computed tomography angiography highlights that LDL lowering therapy affects plaque composition. The primary endpoint of TPV change was not reached; however, VV, MLA, and MLD changed significantly.

The key element for differentiation between normal anatomical variants and pathological deformities is the prior definition of normal ranges for anthropometric parameters of acetabulum according to each age group. Aim of the present study is to analyze the development of the acetabulum in children/adolescents by accurate anthropometric measurements using 3D-CT scans and determine the variations occurring depending on age, gender and/or side. This retrospective observational study included 85 patients (170 hips) under 15 years of age (0-15) undergoing 1.5mm CT scanning for non-hip related reasons. The measurements were performed by 2 board-certified orthopaedic surgeons. Each year of life represented an age group forming a total of 16 groups. Median number of patients per age group was 12 (range 4-16). The anthropometric parameters included acetabular volume, inclination, version, depth (coronal and axial), width (coronal and axial), Tönnis angle as well as anterior and posterior acetabular sector angles. Mean values, range, standard deviation, p-values, intra- and interrater reliability were calculated. All measurement values correlated significantly with age. Statistically, there was no side or gender related difference. Rapid growth phases were observed at the age of 11-12. The inter- and intrarater reliability was high (range ICC 0.8-0.99, Cronbach alpha 0.86-0.99, Bland-Altman good agreement). The present data provides age- and gender-related normative values as well as growth phases describing acetabular morphology. It should help paediatricians as well as paediatric and orthopaedic surgeons as a tool for early diagnosis of deformity and guidance for possible procedures.

We investigated the feasibility of evaluating coronary arteries with a contrast-enhanced (CE) self-navigated sparse isotropic 3D whole heart T1-weighted magnetic resonance imaging (MRI) study sequence. A total of 22 consecutive patients underwent coronary angiography and/or cardiac computed tomography (CT) including cardiac MRI. The image quality was evaluated on a 3-point Likert scale. Inter-reader variability for image quality was analyzed with Cohen’s kappa for the main coronary segments (left circumflex [LCX], left anterior descending [LAD], right coronary artery [RCA]) and the left main trunk (LMT). Inter-reader agreement for image quality of the coronary tree ranged from substantial to perfect, with a Cohen’s kappa of 0.722 (RCAmid) to 1 (LCXprox). The LMT had the best image quality. Image quality of the proximal vessel segments differed significantly from the mid- and distal segments (RCAprox vs. RCAdist, p < 0.05). The LCX segments showed no significant difference in image quality along the vessel length (LCXprox vs. LCXdist, p = n.s.). The mean acquisition time for the study sequence was 553 s (±46 s). Coronary imaging with a sparse 3D whole-heart sequence is feasible in a reasonable amount of time producing good-quality imaging. Image quality was poorer in distal coronary segments and along the entire course of the LCX.

Defining normal anthropometric ranges of proximal femur and femoral head for each age group in children/adolescents is a necessity when differentiating normal anatomical variants from pathological deformities. Aim of this study is to define a set of normal anthropometric parameters based on 3D-CT measurements in normal asymptomatic children/adolescents and analyse the variations arising depending on age, side, and/or gender. Morphology of the proximal femur was retrospectively assessed in 170 hips (85 children, < 15 years). Measurements included covered femoral head volume (CFHV), femoral head diameter (FHD), femoral head extrusion index (FHEI), coronal alpha angle (CAA), lateral centre-edge angle (LCEA), anterior (AOS) and posterior head-neck offset (POS) and femoral neck-shaft angle (FNSA). Correlation analyses as well as inter- and intra-rater reliability were performed. CFHV, LCEA, FHD and AOS/POS increased with age and FHEI, CAA, and FNSA decreased with age. None of the measurements correlated with the side. AOS showed a poor correlation with gender. Rapid growth phases were observed at the age of 1, 7 and 11. The inter- and intra-rater reliability was high (range ICC 0.8–0.99 Cronbach alpha 0.86–0.99). This data delivers a description of growth phases as well as gender and age-correlated reference values of the proximal femoral morphology that could be used by paediatricians and orthopaedic/paediatric surgeons to early diagnose proximal femur deformities and provide guidance in the planning of possible operations.

A survey of hospitals on three continents was performed to assess their infection control preparedness and measures, and their infection rate in hospital health care workers during the COVID-19 pandemic. All surveyed hospitals used similar PPE but differences in preparedness, PPE shortages, and infection rates were reported.

BACKGROUND/AIM:Investigation of the influence of different ultra-low dose computed tomography (ULDCT) protocols on the detection of solid and subsolid nodules in a phantom study.PATIENTS AND METHODS:A chest phantom with pulmonary nodules was scanned with different CT protocols ranging from ultra-low dose settings with spectral shaping to a standard low dose lung cancer screening protocol. Image analysis was performed with different reconstruction algorithms and dedicated computer aided detection (CAD), which was compared to manual readout.RESULTS:The highest sensitivity rates (83%) were achieved for the 90 mAs and 120 mAs protocols when reconstructed with ADMIRE 3 or 5 and manual readout. The only statistically significant difference was found for subsolid nodules with preference of manual readout compared to CAD (p<0.05). Dose levels for the mAs settings ranged from 0.029 to 0.2 mSv.CONCLUSION:Reliable detectability rates for solid nodules were achieved; CAD software did not prove reliable for subsolid nodules.

Development of a deterministic algorithm for automated detection of the Arterial Input Function (AIF) in DCEMRI of colorectal cancer. Using a filter pipeline to determine the AIF region of interest. Comparison to algorithms from literature with mean squared error and quantitative perfusion parameter K-trans. The AIF found by our algorithm has a lower mean squared error (0.0022 +/- 0.0021) in reference to the manual annotation than comparable algorithms. The error of K-trans (21.52 +/- 17.2%) is lower than that of other algorithms. Our algorithm generates reproducible results and thus supports a robust and comparable perfusion analysis.

Normal anatomical variants and pathological deformities of the pediatric hip can only be differentiated after a prior definition of normal ranges for anthropometric parameters with increasing age. Aim of the present study was to provide reliable reference values of the pediatric hip morphometry, using computed tomography (CT)-based rotation-corrected summation images of the pelvis that simulate the widely available plain radiograph-based measurements, but offer the higher precision of the CT technique. This retrospective study included 85 patients (170 hips) under 15 years of age (0-15). The measured anthropometric parameters included femur head extrusion index, lateral center-edge angle, acetabular inclination, Tonnis angle, and femoral neck-shaft angle. Mean values, range, SD, P values, intra-rater, and inter-rater reliability were calculated. All measurements correlated with age. None of the measurements correlated with gender or side. Rapid growth phases were noted in all measurements at the age of 12 (14 in males and 11 in females). The inter-rater and intra-rater reliability was high (range inter/intraclass correlation coefficient 0.926-0.998 Cronbach's alpha 0.986-0.998). The present work provides age- and gender-related normative values of the classically used hip measurements as well as growth phases describing pediatric hip morphology in a broad age range. A discrepancy was noted between the values measured in the current study and the classical X-ray-based reference values in the literature especially for the Tonnis angle and LCEA values. This suggests that the rotation and inclination correction in the CT-based techniques might have the advantage of compensating for a possible overestimation in the conventional X-ray-based methods.

OBJECTIVES:The aim of this study was to establish quantitative CT (qCT) parameters for pathophysiological understanding and clinical use in patients with acute respiratory distress syndrome (ARDS). The most promising parameter is introduced.MATERIALS AND METHODS:28 intubated patients with ARDS obtained a conventional CT scan in end-expiratory breathhold within the first 48 hours after admission to intensive care unit (ICU). Following manual segmentation, 137 volume- and lung weight-associated qCT parameters were correlated with 71 clinical parameters such as blood gases, applied ventilation pressures, pulse contour cardiac output measurements and established status and prognosis scores (SOFA, SAPS II).RESULTS:Of all examined qCT parameters, excess lung weight (ELW), i.e. the difference between a patient's current lung weight and the virtual lung weight of a healthy person at the same height, displayed the most significant results. ELW correlated significantly with the amount of inflated lung tissue [%] (p<0.0001; r = -0.66) and was closely associated with the amount of extravascular lung water (EVLW) (p<0.0001; r = 0.72). More substantially than the oxygenation index (PaO2/FiO2) or any other clinical parameter it correlated with the patients' mean SOFA- (p<0.0001, r = 0.69) and SAPS II-Score (p = 0.0005, r = 0.62). Patients who did not survive intensive care treatment displayed higher values of ELW in the initial CT scans.CONCLUSIONS:ELW could serve as a non-invasive method to quantify the amount of pulmonary oedema. It might serve as an early radiological marker of severity in patients with ARDS.

• The COVID-19 crisis resulted in a variety of physical and mental health issues beyond the viral infection itself, as indicated by an increase in domestic violence. • Radiologists should be aware of typical intimate partner violence (IPV) injury patterns, actively ask potential IPV victims about the cause of injury, and be familiar with support systems for IPV victims of their institutions. • Emergency and radiology departments should review their protocols for identifying and supporting IPV victims, and train their staff to work together to implement these measures during and beyond the COVID-19 crisis.

In the course of a scientific cooperation between the German Mummy Project at the Reiss-Engelhorn-Museen, Mannheim (Germany) and the Musée National d'Histoire et d'Art Luxembourg (Luxembourg), an ancient Egyptian mummy head was analyzed using a multidisciplinary approach including radiocarbon dating, ultra-high resolution computed tomography, physical anthropology, forensic medicine and Egyptology. Dated to the Roman Period, the mummy head belonged to an upper-class woman between 25 and 35 years of age. Computed tomography revealed a lethal blunt force trauma affecting the dorsal parts of the parietal bones, below the intact overlaying soft tissue. Moreover, ancient medical treatment was evidenced through localized shaving of the hair on the affected area, which indicates that efforts have been made to keep the woman alive. This astonishing example of homicide demonstrates the enormous scientific benefit brought by the multidisciplinary investigation of mummified bodies and body parts, and sheds light on life, death and medical care of a woman from Roman Period Egypt.

Purpose: To evaluate the concordance of different CT-based regional wall motion abnormality (RWMA) assessment methods with the presence of a hemodynamically relevant instantaneous wave-free ratio (iwFR) in the supplying coronary artery in patients who underwent both coronary CT-angiography (cCTA) and invasive coronary angiography (ICA). Materials and Methods : All patients included in the study underwent a retrospective coronary cCTA protocol on a 2x192 slice dual-source-CT scanner system and one or more iwFR measurements during ICA. The myocardial segments were evaluated according to American Heart Association 17-segment bulls-eye diagram with three different RWMA assessment methods 1. semiquantitatively: visual (normokinetic/hypokinetic/akinetic) 2. quantitatively: Wall Thickness (15-11/10-6/5-1 mm) 3. quantitatively: Wall Motion (10-6,7/6,6-3,4/3,3-0 mm). Results: 24 patients were included in this analysis. Stenoses in 35 coronary segments were examined with iwFR. 6 stenoses revealed hemodynamically relevant iwFR values. The quantitative assessment method demonstrated the highest sensitivity for the detection of hemodynamically relevant stenosis (83%), followed by the semiquantitative (visual) assessment method (67%). The semiquantitative (visual) assessment method showed the highest specificity (76%), followed by the ventricle wall thickness measurement (48%). The semiquantitative (visual) assessment method showed the highest negative predictive value for the presence of hemodynamically

BACKGROUND:Local recurrence (LR) of retroperitoneal soft tissue sarcoma (RPS) is a common and life-threatening event. The evaluation of the exact anatomical patterns of local recurrence might help to improve local treatment in RPS.METHODS:Of our local database we extracted ten patients with LR of RPS with axial MRI and/or CT datasets of the primary tumor (PT) and the LR. Using the Osirix DICOM viewer Version v.3.9.4 64-bit (Pixmeo, Geneva, Switzerland) we performed a three-step fusion algorithm consisting of: a) 3-point co-registration of the axial datasets depicting the PT and the LR using three abdominal landmarks b) re-orientation of the datasets and c) image fusion. We evaluated the feasibility of this technique with regard to categorizing the localization of LR as within or distant from the PT.RESULTS:Fusion imaging was feasible in seven out of ten patients. In the other three patients anatomical shifting of organs after surgery led to a relevant mismatch of anatomical landmarks and impeded interpretation of the fused images. In five of seven patients with successful fusion imaging, local recurrences were located within the anatomical borders of the primary tumor, in two out of seven patients local recurrences were distant to the primary.CONCLUSIONS:Fusion imaging of primary tumors and local recurrences is feasible in most patients with RPS. Most local recurrences occurred within the anatomical localization of the primary tumor. For further investigations validation of the technique in larger patient cohorts is required.

An 81-year-old woman was admitted to the emergency department with reduced general condition and diarrhea for 2 weeks. Physical examination, sonography of the abdomen and ECG showed no pathologies. Fever was not present. Peripheral O2-saturation was 86%. Laboratory test showed an infection constellation. A non-enhanced (NE) chest CT revealed peripheral ground-glass opacity (GGO) with visible intralobular lines ("crazy-paving") of the left upper lobe (Figure 1A/B). Although this is a typical infiltrate pattern of COVID-19 pneumonia, the unilateral changes were consistent with an intermediate appearance of COVID-19 pneumonia according to the recently published RSNA COVID-19 reporting consensus statement, where the intermediate appearance is defined as presence of multifocal, diffuse, perihilar, or unilateral GGO (…) and absence of typical features, in our case the missing bilaterality (Simpson et al., 2020Simpson S. Kay F.U. Abbara S. Bhalla S. Chung J.H. Chung M. et al.Radiological society of North America expert consensus statement on reporting chest CT findings related to COVID-19. Endorsed by the society of thoracic radiology, the American college of radiology, and RSNA.J. Thorac. Imaging. 2020; Crossref PubMed Scopus (434) Google Scholar). As further testing revealed elevated D-Dimer as well as a negative RT-PCR regarding Covid-19, a contrast-enhanced (CE) chest CT was indicated 2 days after initial NE-chest CT. In this CE-chest CT the aforementioned ground-glass opacity can be depicted as dome-shaped, pleural-based opacification, consistent with a post-infarction pneumonia (Figure 1 C) due to pulmonary embolism (PE) (Figure 1 D). The patient was admitted to ICU because of progressive right heart compromise. The PE was treated with low-molecular-weight heparin. This image shows that structured reporting of possible COVID-19 CT findings can lead the clinician to e.g. further testing and has potential to accelerate managing of patients through the workup during these difficult times, especially under the ongoing discussion of the value of D-dimer in COVID-19 patients (Grillet et al., 2020Grillet F. Behr J. Calame P. Aubry S. Delabrousse E. Acute pulmonary embolism associated with COVID-19 pneumonia detected by pulmonary CT angiography.Radiology. 2020; 201544Crossref PubMed Scopus (396) Google Scholar). The authors declare that they have no conflict of interest. There is no Funding Source for the present manuscript.

Background: Machine-learning-based computed-tomography-derived fractional flow reserve (CT-FFRML) obtains a hemodynamic index in coronary arteries. We examined whether it could reduce the number of invasive coronary angiographies (ICA) showing no obstructive lesions. We further compared CT-FFRML-derived measurements to clinical and CT-derived scores. Methods: We retrospectively selected 88 patients (63 ± 11years, 74% male) with chronic coronary syndrome (CCS) who underwent clinically indicated coronary computed tomography angiography (cCTA) and ICA. cCTA image data were processed with an on-site prototype CT-FFRML software. Results: CT-FFRML revealed an index of >0.80 in coronary vessels of 48 (55%) patients. This finding was corroborated in 45 (94%) patients by ICA, yet three (6%) received revascularization. In patients with an index ≤ 0.80, three (8%) of 40 were identified as false positive. A total of 48 (55%) patients could have been retained from ICA. CT-FFRML (AUC = 0.96, p ≤ 0.0001) demonstrated a higher diagnostic accuracy compared to the pretest probability or CT-derived scores and showed an excellent sensitivity (93%), specificity (94%), positive predictive value (PPV; 93%) and negative predictive value (NPV; 94%). Conclusion: CT-FFRML could be beneficial for clinical practice, as it may identify patients with CAD without hemodynamical significant stenosis, and may thus reduce the rate of ICA without necessity for coronary intervention.