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Objectives: To evaluate the image quality (IQ) of a spectral photon-counting CT (SPCCT) using filtered back projection (FBP) and hybrid iterative reconstruction (IR) algorithms (iDose4), in comparison with a dual-layer CT (DLCT) system, and to choose the best image quality according to the IR level for SPCCT. Methods: Two phantoms were scanned using a standard lung protocol (120 kVp, 40 mAs) with SPCCT and DLCT systems. Raw data were reconstructed using FBP and 9 iDose4 levels (i1/i2/i3/i4/i5/i6/i7/i9/i11) for SPCCT and 7 for DLCT (i1/i2/i3/i4/i5/i6/i7). Noise power spectrum and task-based transfer function (TTF) were computed. Detectability index (d′) was computed for detection of 4 mm ground-glass nodule (GGN) and solid nodule. Two chest radiologists performed an IQ evaluation (noise/nodule sharpness/nodule conspicuity/overall IQ) in consensus, and chose the best image for SPCCT. Results: Noise magnitude was −47% ± 2% lower on average with SPCCT than with DLCT for iDose4 range from i1 to i6. Average NPS spatial frequencies increased for SPCCT in comparison with DLCT. TTF also increased, except for the air insert with FBP, and i1/i2/i3. Higher detectability was found for SPCCT for both GGN and solid nodules. IQ for both types of nodule was rated consistently higher with SPCCT than with DLCT for the same iDose4 level. For SPCCT and both nodules, the scores for noise and conspicuity improved with increasing iDose4 level. iDose4 level 6 provided the best subjective IQ for both types of nodule. Conclusions: Higher IQ for GGN and solid nodules was demonstrated with SPCCT compared with DLCT with better detectability using iDose4. Key Points: Using spectral photon-counting CT compared with dual-layer CT, noise magnitude was reduced with improvements in spatial resolution and detectability of ground-glass nodules and solid lung nodules.As the iDose4level increased, noise magnitude was reduced and detectability of ground-glass and solid lung nodules was better for both CT systems.For spectral photon-counting CT imaging, two chest radiologists determined iDose4level 6 as the best image quality for detecting ground-glass nodules and solid lung nodules.

Purpose The purpose of this study was to assess the impact of advanced modeled iterative reconstruction (ADMIRE) algorithm and dose levels on the accuracy of Hounsfield unit (HU) measurement, image noise and contrast-to-noise ratio (CNR) in virtual monochromatic images (VMIs) with low iodine concentrations, and the accuracy of iodine quantification. Materials and methods A CT phantom was scanned with dual-source CT using abdomen-pelvis examination parameters at four dose levels: 5, 8, 11 and 20 mGy. Images were reconstructed using filtered-back projection (FBP) and ADMIRE levels 3 and 5 (A3-A5). HU accuracy was assessed calculating the root-mean-square deviation (RMSDHU). Image noise and CNR were computed on VMIs at 40/50/60/70 keV for 4 iodine inserts with 0.5, 1, 2 and 5 mg/mL concentrations. Accuracy of iodine quantification was assessed by the RMSDiodine and iodine bias (IB). Results The RMSDHU decreased significantly as the dose levels increased compared to 5 mGy, except for 8 mGy with A3 (P = 0.380) and with A5 level (P = 0.945). Noise increased by 63.0 ± 3.0 (standard deviation [SD])% from 20 mGy to 5 mGy. Noise decreased significantly by -53.8 ± 0.9 (SD) % with A5 compared to FBP. The CNR decreased by -43.1 ± 6.5 (SD)% from 20 mGy to 5 mGy. It increased using ADMIRE, and as the ADMIRE levels increased. The RMSDiodine and IB decreased as the dose level increased, and this was similar for all reconstruction types. Conclusion ADMIRE strongly improves image quality in VMIs and slightly improves HU accuracy but does not affect the accuracy of iodine quantification.

BACKGROUND: Many computed tomography (CT) navigation systems have been developed to help radiologists improve the accuracy and safety of the procedure. We evaluated the accuracy of one CT computer-assisted guided procedure with different reduction dose protocols. METHODS: A total of 128 punctures were randomly made by two operators on two different anthropomorphic phantoms. The tube voltage was fixed to 100 kVp. Tube currents (mAs) were defined to obtain 4 dose levels: 180 mAs (D1.00), 90 mAs (D0.50), 45 mAs (D0.25) and 15 mAs (D0.10) with respective volume CT dose index (CTDIvol) of 7.02, 3.52, 1.75 and 0.59 mGy. The raw data were reconstructed using level 2 of advanced model-based iterative reconstruction (ADMIRE) (A2) for D1.00, A3 for D0.50, A4 for D0.25 and A5 for D0.10. Two 12-mm targets per phantom were selected. The mean Euclidean distance (EuD) between the tip of the needle and the isocenter of the target was measured for each puncture. The different measures were compared by paired Student’s t-tests. RESULTS: The mean EuD was 7.0±3.1 mm for the 128 punctures performed. Regardless of which phantom was considered, no significant difference in accuracy occurred between the 4 dose levels, which were 7.1±3.5 mm for D1.00; 7.1±3.1 mm for D0.50; 7.2±3.0 mm for D0.25 and 6.6±2.6 mm for D0.10. CONCLUSIONS: Abdominal CT-guided procedures, using computer-assisted navigation and iterative reconstruction algorithms, allow precise punctures on anthropomorphic phantoms with a dose reduction of −92% compared to a standard protocol.

To compare the organ-dose and effective-dose (E) delivered to the patient during percutaneous vertebroplasty (PVP) of one thoracic or lumbar vertebra performed under CT guidance or using a fixed C-arm.Consecutive adult patients undergoing PVP of one vertebra under CT-guidance, with optimized protocol and training of physicians, or using a fixed C-arm were retrospectively included from January 2016 to June 2017. Organ-doses were computed on 16 organs using CT Expo 2.4 software for the CT procedures and PCXMC 2.0 for the fixed C-arm procedures. E was also computed with both software. Dosimetric values per anatomic locations for all procedures were compared using the paired Mann-Whitney-Wilcoxon test.In total, 73 patients were analysed (27 men and 46 women, mean age 78 ± 10 years) among whom 35 (48%) underwent PVP under CT guidance and 38 (52%) PVP using a fixed C-arm. The median E was 11.31 [6.54; 15.82] mSv for all PVPs performed under CT guidance and 5.58 [3.33; 8.71] mSv for fixed C-arm and the differences was significant (p0.001). For lumbar PVP, the organ doses of stomach, liver and colon were significantly higher with CT-scan than with the fixed C-arm: 97% (p=0.02); 21% (p=0.099) and 375% (p=0.002), respectively. For thoracic PVP, the lung organ dose was significantly higher with CT-scan than with the fixed C-arm (127%; p0.001) and the oesophagus organ doses were not significantly different (p = 0.626).This study showed that the E and the organ dose on directly exposed organs were both higher for PVP performed under CT-guidance than with the fixed C-arm.

Purpose To assess the impact of dose reduction and the use of an advanced modeled iterative reconstruction algorithm (ADMIRE) on image quality in low-energy monochromatic images from a dual-source dual energy computed tomography CT (DSCT) platform. Materials and methods Acquisitions on an image-quality phantom were performed using DSCT equipment with 100/Sn150 kVp for four dose levels (CTDIvol: 20/11/8/5mGy). Raw data were reconstructed for six energy levels (40/50/60/70/80/100 keV) using filtered back projection and two levels of ADMIRE (A3/A5). Noise power spectrum (NPS) and task-based transfer function (TTF) were calculated on virtual monoenergetic images (VMIs). Detectability index (d′) was computed to model the detection task of two enhanced iodine lesions as function of keV. Results Noise-magnitude was significantly reduced between 40 to 70 keV by −56 ± 0% (SD) (range: −56%–−55%) with FBP; −56 ± 0% (SD) (−56%–−56%) with A3; and −57 ± 1% (SD) (range: −57%–−56%) with A5. The average spatial frequency of the NPS peaked at 70 keV and decreased as ADMIRE level increased. TTF values at 50% were greatest at 40 keV and shifted towards lower frequencies as the keV increased. The detectability of both lesions increased with increasing dose level and ADMIRE level. For the simulated lesion with iodine at 2 mg/mL, d’ values peaked at 70 keV for all reconstruction types, except for A3 at 20 mGy and A5 at 11 and 20 mGy, where d’ peaked at 60 keV. For the other simulated lesion, d’ values were highest at 40 keV and decreased beyond. Conclusion At low keV on VMIs, this study confirms that iterative reconstruction reduces the noise magnitude, improves the spatial resolution and increases the detectability of enhanced iodine lesions.

The purpose of this study was to compare the diagnostic performance of ultra-low dose (ULD) to that of standard (STD) computed tomography (CT) for the diagnosis of non-traumatic abdominal emergencies using clinical follow-up as reference standard.All consecutive patients requiring emergency abdomen-pelvic CT examination from March 2017 to September 2017 were prospectively included. ULD and STD CTs were acquired after intravenous administration iodinated contrast medium (portal phase). CT acquisitions were performed at 125mAs for STD and 55mAs for ULD. Diagnostic performance was retrospectively evaluated on ULD and STD CTs using clinical follow-up as a reference diagnosis.A total of 308 CT examinations from 308 patients (145 men; mean age 59.1±20.7 (SD) years; age range: 18-96 years) were included; among which 241/308 (78.2%) showed abnormal findings. The effective dose was significantly lower with the ULD protocol (1.55±1.03 [SD] mSv) than with the STD (3.67±2.56 [SD] mSv) (P0.001). Sensitivity was significantly lower for the ULD protocol (85.5% [95%CI: 80.4-89.4]) than for the STD (93.4% [95%CI: 89.4-95.9], P0.001) whereas specificities were similar (94.0% [95%CI: 85.1-98.0] vs. 95.5% [95%CI: 87.0-98.9], respectively). ULD sensitivity was equivalent to STD for bowel obstruction and colitis/diverticulitis (96.4% [95%CI: 87.0-99.6] and 86.5% [95%CI: 74.3-93.5] for ULD vs. 96.4% [95%CI: 87.0-99.6] and 88.5% [95%CI: 76.5-94.9] for STD, respectively) but lower for appendicitis, pyelonephritis, abscesses and renal colic (75.0% [95%CI: 57.6-86.9]; 77.3% [95%CI: 56.0-90.1]; 90.5% [95%CI: 69.6-98.4] and 85% [95%CI: 62.9-95.4] for ULD vs. 93.8% [95%CI: 78.6-99.2]; 95.5% [95%CI: 76.2-100.0]; 100.0% [95%CI: 81.4-100.0] and 100.0% [95%CI: 80.6-100.0] for STD, respectively). Sensitivities were significantly different between the two protocols only for appendicitis (P=0.041).In an emergency context, for patients with non-traumatic abdominal emergencies, ULD-CT showed inferior diagnostic performance compared to STD-CT for most abdominal conditions except for bowel obstruction and colitis/diverticulitis detection.

To compare the spectral performance of dual-energy CT (DECT) platforms using task-based image quality assessment based on phantom data. Two CT phantoms were scanned on four DECT platforms: fast kV-switching CT (KVSCT), split filter CT (SFCT), dual-source CT (DSCT), and dual-layer CT (DLCT). Acquisitions on each phantom were performed using classical parameters of abdomen-pelvic examination and a CTDIvol at 10 mGy. Noise power spectrum (NPS) and task-based transfer function (TTF) were evaluated from 40 to 140 keV of virtual monoenergetic images. A detectability index (d′) was computed to model the detection task of two contrast-enhanced lesions as function of keV. The noise magnitude decreased from 40 to 70 keV for all DECT platforms, and the highest noise magnitude values were found for KVSCT and SFCT and the lowest for DSCT and DLCT. The average NPS spatial frequency shifted towards lower frequencies as the energy level increased for all DECT platforms, smoothing the image texture. TTF values decreased with the increase of keV deteriorating the spatial resolution. For both simulated lesions, higher detectability (d′ value) was obtained at 40 keV for DLCT, DSCT, and SFCT but at 70 keV for KVSCT. The detectability of both simulated lesions was highest for DLCT and DSCT. Highest detectability was found for DLCT for the lowest energy levels. The task-based image quality assessment used for the first time for DECT acquisitions showed the benefit of using low keV for the detection of contrast-enhanced lesions. • Detectability of both simulated contrast-enhanced lesions was higher for dual-layer CT for the lowest energy levels. • The image noise increased and the image texture changed for the lowest energy levels. • The detectability of both simulated contrast-enhanced lesions was highest at 40 keV for all dual-energy CT platforms except for fast kV-switching platform.

To compare diagnosis performance and effective dose of ultra-low-dose CT (ULD CT) versus radiographs in suspected spinal or pelvic ring or hip fracture for minor trauma. ULD CT, in addition to radiography, was prospectively performed in consecutive patients admitted to the emergency department for minor traumas, during working hours over 2 months. Presence of a recent fracture was assessed by two blind radiologists independently. Sensitivities and specificities were estimated using the best valuable comparator (BVC) as a reference and using a latent class model in Bayesian inference (BLCM). Dosimetric indicators were recorded and effective doses (E) were calculated using conversion coefficient. Eighty areas were analyzed in 69 patients, including 22 dorsal spine, 28 lumbar spine, and 30 pelvic ring/hip. Thirty-six fractures (45%) were observed. Applying the BVC method, depending on location, ULD CT sensitivity was 80 to 100% for reader 1 and 85 to 100% for reader 2, whereas radiographic sensitivity was 60 to 85% for reader 1 and 50 to 92% for reader 2. With BLCM approach for reader 2, ULD CT sensitivity for all locations/dorsal spine/lumbar spine and pelvic ring-hip was 87.1/75.9/84.2/76.9% respectively. Corresponding radiograph sensitivity was 73.8, 54.8, 80.4, and 68.7%. Effective doses of ULD CT were similar to radiographs for dorsal and hip locations whereas for lumbar spine, ULD CT effective dose was 1.83 ± 0.59 mSv compared with 0.96 ± 0.59 mSv (p < 0.001). Sensitivity for fracture detection was higher for ULD CT compared with radiographs with an effective dose comparable to radiographs. • Ultra-low-dose spine and pelvis CT demonstrates better fracture detection when compared with radiographs. • The effective dose of ultra-low-dose spine and pelvis CT scan and radiographs is comparable. • Replacement of radiographs by ULD CT in daily practice for trauma patients is an option to consider and should be evaluated by a randomized trial.

To establish national reference levels (RLs) in interventional procedures under CT guidance as required by the 2013/59/Euratom European Directive. Seventeen categories of interventional procedures in thoracic, abdominopelvic, and osteoarticular specialties (percutaneous infiltration, vertebroplasty, biopsy, drainage, tumor destruction) were analyzed. Total dose length product (DLP), number of helical acquisitions (NH), and total DLP for helical, sequential, or fluoroscopic acquisitions were recorded for 10 to 20 patients per procedure at each center. RLs were calculated as the 3rd quartiles of the distributions and target values for optimization process (TVOs) as the median. RLs and TVOs were compared with previously published studies. Results on 5001 procedures from 49 centers confirmed the great variability in patient dose for the same category of procedures. RLs were proposed for the DLPs and NHs in the seventeen categories. RLs in terms of DLP and NH were 375 mGy.cm and 2 NH for spinal or peri-spinal infiltration, 1630 mGy.cm and 3 NH for vertebroplasty, 845 mGy.cm and 4 NH for biopsy, 1950 mGy.cm and 8 NH for destruction of tumors, and 1090 mGy.cm and 5 NH for drainage. DLP and NH increased with the complexity of procedures. This study was the first nationwide multicentric survey to propose RLs for interventional procedures under CT guidance. Heterogeneity of practice in centers were found with different levels of patient doses for the same procedure. The proposed RLs will allow imaging departments to benchmark their practice with others and optimize their protocols. • National reference levels are proposed for 17 categories of interventional procedures under CT guidance. • Reference levels are useful for benchmarking practices and optimizing protocols. • Reference levels are proposed for dose length product and the number of helical acquisitions.

International audience; Peripherally inserted central catheters (PICCs) are central venous catheters commonly used for administration of chemotherapy, prolonged antibiotic treatment, or parenteral nutrition. It is advisable to use the PICC with the fewest lumens and the smallest possible diameter to reduce major complications. A pharmaceutical analysis and validation of PICC requests was designed to improve efficiency and patient safety. The aim of this study was to evaluate the impact of pharmaceutical interventions (PIs) by the clinical pharmacist in the PICC process.Methods: A prospective pilot study was conducted in a French university hospital. Four categories of PIs were defined according to the different stages of the PICC insertion process: before insertion to validate with the physician the relevance of the request and the choice of PICC model (PI applicant); during insertion (PI installer); during usage by nurses for analysis of drug incompatibilities (PI user); and at hospital discharge for reassessment of the device maintenance (PI reassessment). Each PI applicant was designated a potential harm from 1 to 4, with a cut-off of 2 representing harm for the patient.Results: Over 6 months, 277 requests were analysed and 297 PIs were completed (109 applicants, 98 installers, 84 users, and 6 PIs for reassessment). The acceptance rate by the physicians was 93.6%. 52% of the PI applicants had a potential harm of 2 or more. 5% of PICC requests were refused by the pharmacist due to an inappropriate choice of device. A total of 207 (74.7%) of the requests analysed by the clinical pharmacist led to insertion.Conclusions: The implementation of a clinical pharmacy activity applied to PICC requests analysis and validation leads to improved patient care by securing the PICC circuit. This analysis demonstrates the beneficial role of the clinical pharmacist in PIs associated with medical devices.

For long, complex procedures in interventional radiology (IR) or in interventional cardiology (IC), the skin dose can be high and induce skin injuries. To improve patient follow-up, it is essential to measure and locate the peak skin dose (PSD). PSD can be measured using dosimeters or computed by skin dose calculation software solutions. Recently, a study was published (e.g. Malchair F et al Phys Med 2020; 80:75–83) listing all the software solutions developed and available and compared them in operation as regards accuracy of the calculated PSD and generated dose map. Similarities and differences exist between these different software packages, which are discussed here. The accuracy of PSD calculated on phantom studies with these software solutions are within ± 25% and poorer in patient studies. Improvements are therefore required for manufacturers of both software and IR systems. The medical physicists also have an important role to play in setting up and monitoring the dose in these software solutions to ensure the accuracy of the calculated PSD.

The original version of this article, published on 02 May 2020, unfortunately contained a mistake.

To determine the best compromise between low radiation dose and suitable image quality for the detection of lytic and sclerotic bone lesions of the lumbar spine and pelvis. A phantom was scanned using the routine protocol (STD, 13 mGy) and six decreasing dose levels. Raw data were reconstructed using level 3 of iterative reconstruction (IR3) with 1-mm slice thickness for the STD protocol and highest IR levels with 3-mm slice thickness for the others. CTDIvol was used for radiation dose assessment. Quantitative criteria (noise power spectrum [NPS], task-based transfer function [TTF], and the detectability index [d′]), as well as qualitative analysis, were used to compare protocols. NPS and TTF were computed using specific software (imQuest). d′ was computed for two imaging tasks: lytic and sclerotic bone lesions. A subjective analysis was performed to validate the image quality obtained on the anthropomorphic phantom with the different dose values. Similar d′ values were found for CTDIvol from 3 to 4 mGy with IR4 and from 1 to 2 mGy for IR5 compared with d′ values using the STD protocol. Image quality was validated subjectively for IR4 but rejected for IR5 (image smoothing). Finally, for the same d′, the dose was reduced by 74% compared with the STD protocol, with the CTDIvol being 3.4 mGy for the lumbar spine and for the pelvis. A dose level as low as 3.4 mGy, in association with high levels of IR, provides suitable image quality for the detection of lytic and sclerotic bone lesions of the lumbar spine and pelvis. • A CTDI vol of 3.4 mGy, in association with high iterative reconstruction level, provides suitable image quality for the detection of lytic and sclerotic bone lesions, both at objective and subjective analysis. • Compared with the standard protocol, radiation dose can be reduced up to 74% for the lumbar spine and pelvis. • A task-based image quality assessment using the detectability index represents an objective method for the assessment of image quality and bridges the gap between complex physical metrics and subjective image analysis.

International audience; Study objective:To evaluate the diagnostic performance of chest ultralow-dose computed tomography (CT) compared with chestradiograph for minor blunt thoracic trauma.Methods:One hundred sixty patients with minor blunt thoracic trauma were evaluatedfirst by chest radiograph and subsequentlywith a double-acquisition nonenhanced chest CT protocol: reference CT and ultralow-dose CT with iterative reconstruction. Twostudy radiologists independently assessed injuries with a structured report and subjective image quality and calculated certaintyof diagnostic confidence level.Results:Ultralow-dose CT had a sensitivity and specificity of 100% compared with reference CT in the detection of injuries (187lesions) in 104 patients. Chest radiograph detected abnormalities in 82 patients (79% of the population), with lower sensitivityand specificity compared with ultralow-dose CT (P

International audience; Les innovations de l’imagerie diagnostique et de la radiologie interventionnelle ont permis l’optimisation de la prise en charge des patients atteints de pathologies aortiques. Au stade aigu, le risque vital est à considérer en priorité. La visualisation par scanner de toute l’aorte permet de décider de la meilleur option entre chirurgie et radiologie interventionnelle (fenestration, endoprothèse couverte, endoprothèse périphérique). Les algorithmes décisionnels, basés sur la compréhension des complications et risques évolutifs, ont été modifiés notamment pour les dissections aortiques. Au stade chronique, le médecin vasculaire et le généraliste doivent surveiller l’aorte et les facteurs de risques cardiovasculaires afin d’éviter les complications. L’IRM est alors indiquée.

Purpose The purpose of this study was to compare the effect of two deep learning image reconstruction (DLR) algorithms in chest computed tomography (CT) with different clinical indications. Material and methods Acquisitions on image quality and anthropomorphic phantoms were performed at six dose levels (CTDIvol: 10/7.5/5/2.5/1/0.5mGy) on two CT scanners equipped with two different DLR algorithms (TrueFidelityTM and AiCE). Raw data were reconstructed using the filtered back-projection (FBP) and the lowest/intermediate/highest DLR levels (L-DLR/M-DLR/H-DLR) of each algorithm. Noise power spectrum, task-based transfer function (TTF) and detectability index (d’) were computed: d’ modelled detection of a soft tissue mediastinal nodule, ground-glass opacity, or high-contrast pulmonary lesion. Subjective image quality of anthropomorphic phantom images was analyzed by two radiologists. Results For the L-DLR/M-DLR levels, the noise magnitude was lower with TrueFidelityTM than with AiCE from 2.5 to 10 mGy. For H-DLR, noise magnitude was lower with AiCE . For L-DLR and M-DLR, the average NPS spatial frequency (fav) values were greater for AiCE except for 0.5 mGy. For H-DLR levels, fav was greater for TrueFidelityTM than for AiCE. TTF50% values were greater with AiCE for the air insert, and lower than TrueFidelityTM for the polyethylene insert. From 2.5 to10 mGy, d’ was greater for AiCE than for TrueFidelityTM for H-DLR for all lesions, but similar for L-DLR and M-DLR. Image quality was rated clinically appropriate for all levels of both algorithms, for dose from 2.5 to 10 mGy, except for L-DLR of AiCE. Conclusion DLR algorithms reduce the image-noise and improve lesion detectability. Their operations and properties impacted both noise-texture and spatial resolution.

International audience; Background: Ultra low dose chest computed tomography (CT) acquisitions have been used for selected emergency room patients with acute dyspnea or minor thoracic trauma. The purpose of this study was to evaluate the diagnostic performance of ultra-low-dose (ULD) chest CT for detecting viral pneumonia patterns compared to standard (STD) dose chest CT.Methods: All consecutive adult patients with two non-enhanced chest CT acquisitions, one STD and one ULD, for suspicion of viral pneumonia between March 5th and April 2nd 2020 were included. CT results were divided into two groups: non-viral pneumonia CT or compatible with viral pneumonia CT based on viral pneumonia CT patterns: ground-glass opacity (GGO), consolidation, crazy paving, air bronchogram signs and fibrous stripes. The diagnostic performance of ULD CT for suspicion of viral pneumonia was evaluated. For CTs compatible with viral pneumonia, CT pattern detection on ULD CT was assessed and STD CT was used as a reference.Results: The study included 380 patients with 97 CTs (25.5%) compatible with viral pneumonia. The mean effective doses (EDs) were 1.66 (1.29; 2.18) mSv for STD and 0.20 (0.18; 0.22) mSv for ULD CT (P

Purpose To quantify the hemodynamic consequences of thoracic endovascular aortic repair (TEVAR) by comparing the preoperative and postoperative wall shear stress (WSS) and vorticity profiles on computational fluid dynamics (CFD) simulations. Materials and Methods The pre- and postoperative computed tomography (CT) scans from 20 consecutive patients (median age 69 years, range 20–87) treated for different thoracic aortic pathologies (11 aneurysms, 5 false aneurysms, 3 penetrating ulcers, and 1 traumatic aortic rupture) were segmented to construct patient-specific CFD models using a meshless code. The simulations were run over the cardiac cycle, and the WSS and vorticity values measured at the proximal and distal landing zones were compared. Results The CFD runs provided 4-dimensional simulations of blood flow in all patients. WSS and vorticity profiles at the proximal landing zone (located in zones 0–3 in 15 patients) varied in 18 and 20 of the cases, respectively; WSS was increased in 11 cases and the vorticity in 9. Pre- and postoperative WSS median values were 4.19 and 4.90 Pa, respectively. Vorticity median values were 40.38 and 39.17 Hz, respectively. Conclusion TEVAR induces functional alterations in the native thoracic aorta, though the prognostic significance of these changes is still unknown. CFD appears to be a valuable tool to explore aortic hemodynamics, and its application in a larger series would help define a predictive role for these hemodynamic assessments.

To validate the performance of an automatic tool to estimate a patient’s peak skin dose (PSD) and a skin dose map from data collected by a radiation dose management system (RDMS) during interventional procedures. In total, 288 eligible consecutive patients undergoing abdominopelvic embolisation or planned coronary angioplasty using radiochromic films were screened between June 2018 and March 2019. For 98 included patients, PSD was measured using radiochromic films (PSDFilm) and computed by RDMS (PSDRDMS) using one flat and two anthropomorphic phantoms. Statistical concordance between PSDFilm and PSDRDMS was computed with Lin’s concordance correlation coefficient and clinical concordance with the Bland and Altman graphic; values were compared using the paired Mann-Whitney-Wilcoxon test. In total, 190/288 patients were excluded and 98 patients were analysed (69 men, mean age 66 ± 14 years). The PSDFilm median (1st; 3rd quartile) was 0.59 Gy (0.40; 1.08). PSDRDMS was 0.62 Gy (0.43; 1.22) for the flat phantom and 0.62 Gy (0.42; 1.19) for anthropomorphic phantoms. The concordance between PSDFilm and PSDRDMS was good for both phantoms (flat: 0.94 [0.91; 0.95]; anthropomorphic 0.94 [0.91; 0.96]). Compared with the values of PSDFilm, the values of PSDRDMS were significantly increased by 5% (− 4%; 16%) for flat phantom (p = 0.001) and 7% (− 6%; 22%) for anthropomorphic phantoms (p = 0.002) for vascular procedures and 9% (− 4%; 26%, p = 0.01) and 6% (− 4%; 23%, p = 0.02) for cardiac procedures, respectively. Dose map representations matched for most patients. The gaps identified were due to table displacement during fluoroscopy events and the use of a wedge filter. The RDMS skin dose map tool allowed the computation of the PSD and skin dose distribution for all patients with fewer constraints than radiochromic films. However, the computed PSD was overestimated, increasing the number of patients requiring follow-up. • A good concordance correlation was identified between the peak skin dose (PSD) values measured with radiochromic films and estimated with the radiation dose management system (RDMS) skin dose map tool. • Differences were related to table displacement during fluoroscopy events and the use of a wedge filter, which are not accounted in the Digital Imaging and Communications in Medicine Radiation Dose Structured Reports. • For all procedures, the estimated PSDs were significantly higher than the measured PSDs by 5% (− 4%; 18%) for flat phantom (p

Purpose To evaluate the feasibility of prostatic artery embolization in patients with low-risk prostate cancer (PC) under active surveillance (AS). Methods This monocentric prospective pilot study, running from June 2018 to June 2019, included 10 patients with low-risk PC under AS, median age 72 years (range, 62–77 years), with a unilateral focal lesion visible on magnetic resonance (MR) imaging, with Prostate Imaging Reporting and Data System v2 score ≥3/5 confirmed by multiparametric MR imaging-targeted biopsy and Gleason score 6. The patients underwent unilateral prostatic artery embolization with 300–500 μm Embospheres in the affected prostatic lobe. The primary endpoint was technical feasibility (prostate and no off-target ischemia in the imaging). The secondary endpoints included safety, negative biopsies/MR imaging response/functional outcomes at 6 months, and oncologic efficacy at 1 year. Results Embolization was successfully achieved in all patients; prostate ischemia was confirmed on multiparametric MR imaging, and no off-target ischemia was reported. No major complications were reported. Four patients (40%) presented with both negative targeted and systematic biopsies at 6 months. No lesions were seen on the MR imaging in 30% of patients. The mean International Prostate Symptom Score and International Index of Erectile Function score were 7 and 19 and 5 and 20 at baseline and 6 months, respectively, with no significant difference. Nine patients (90%) were still under AS at 1 year. One patient (10%) had PC progression outside the target lesion and was switched over to curative radiotherapy. Conclusions Prostatic artery embolization is feasible and appears safe for prostate cancer patients under AS, with no impact on erectile function or continence status. These results justify the pursuit of further studies.

To determine the impact of the COVID-19 on the CT activities in French radiological centers during the epidemic peak. A cross-sectional prospective CT scan survey was conducted between March 16 and April 12, 2020, in accordance with the local IRB. Seven hundred nine radiology centers were invited to participate in a weekly online survey. Numbers of CT examinations related to COVID-19 including at least chest (CTcovid) and whole chest CT scan activities (CTchest) were recorded each week. A sub-analysis on French departments was performed during the 4 weeks of the study. The impact of the number of RT-PCRs (reverse transcriptase polymerase chain reactions) on the CT workflow was tested using two-sample t test and Pearson’s test. Five hundred seventy-seven structures finally registered (78%) with mean response numbers of 336 ± 18.9 (323; 351). Mean CTchest activity per radiologic structure ranged from 75.8 ± 133 (0–1444) on week 12 to 99.3 ± 138.6 (0–1147) on week 13. Mean ratio of CTcovid on CTchest varied from 0.36 to 0.59 on week 12 and week 14 respectively. There was a significant relationship between the number of RT-PCR performed and the number of CTcovid (r = 0.73, p = 3.10−16) but no link with the number of positive RT-PCR results. In case of local high density COVID-19, CT workflow is strongly modified and redirected to the management of these specific patients. • Over the 4-week survey period, 117,686 chest CT (CT total ) were performed among the responding centers, including 61,784 (52%) CT performed for COVID-19 (CT covid ). • Across the country, the ratio CT covid /CT total varied from 0.36 to 0.59 and depended significantly on the local epidemic density (p = 0.003). • In clinical practice, in a context of growing epidemic, in France, chest CT was used as a surrogate to RT-PCR for patient triage.

To assess the impact on image quality and dose reduction of a new deep learning image reconstruction (DLIR) algorithm compared with a hybrid iterative reconstruction (IR) algorithm. Data acquisitions were performed at seven dose levels (CTDIvol : 15/10/7.5/5/2.5/1/0.5 mGy) using a standard phantom designed for image quality assessment. Raw data were reconstructed using the filtered back projection (FBP), two levels of IR (ASiR-V50% (AV50); ASiR-V100% (AV100)), and three levels of DLIR (TrueFidelity™ low, medium, high). Noise power spectrum (NPS) and task-based transfer function (TTF) were computed. Detectability index (d′) was computed to model a large mass in the liver, a small calcification, and a small subtle lesion with low contrast. NPS peaks were higher with AV50 than with all DLIR levels and only higher with DLIR-H than with AV100. The average NPS spatial frequencies were higher with DLIR than with IR. For all DLIR levels, TTF50% obtained with DLIR was higher than that with IR. d′ was higher with DLIR than with AV50 but lower with DLIR-L and DLIR-M than with AV100. d′ values were higher with DLIR-H than with AV100 for the small low-contrast lesion (10 ± 4%) and in the same range for the other simulated lesions. New DLIR algorithm reduced noise and improved spatial resolution and detectability without changing the noise texture. Images obtained with DLIR seem to indicate a greater potential for dose optimization than those with hybrid IR. • This study assessed the impact on image quality and radiation dose of a new deep learning image reconstruction (DLIR) algorithm as compared with hybrid iterative reconstruction (IR) algorithm. • The new DLIR algorithm reduced noise and improved spatial resolution and detectability without perceived alteration of the texture, commonly reported with IR. • As compared with IR, DLIR seems to open further possibility of dose optimization.

Introduction Lung cancer (LC) has the highest cancer mortality worldwide with poor prognosis. Screening with low-dose computed tomography (LDCT) in populations highly exposed to tobacco has been proposed to improve LC prognosis. Our objective was to perform a systematic review and meta-analysis to evaluate the efficacy of screening by LDCT compared with any other intervention in populations who reported tobacco consumption for more than 15 years on LC and overall mortality. Methods We searched randomised controlled trials (RCTs) studying screening by LDCT compared with any other intervention in a population who reported an average smoking history greater than 15 pack-years from inception until the 19th February 2018 using Medline and Cochrane Library databases. Publication selection and data extraction were made independently by two double-blind reviewers. Results Seven RCTs were included in the meta-analysis which corresponds to 84,558 participants. A significant relative reduction of LC-specific mortality of 17% (risk ratio [RR] = 0.83, 95% confidence interval [CI]: 0.76–0.91) and a relative reduction of overall mortality of 4% (RR = 0.96, 95% CI: 0.92–1.00) was observed in the screening group compared with the control group. Conclusion In populations highly exposed to tobacco, screening by LDCT reduces lung cancer mortality.

Purpose The purpose of this study was to assess the impact of tin filter (TF) on X-ray beam quality, image quality and radiation dose and its suitability for routine use for chest and lumbar-spine/pelvis-hip ultralow-dose (ULD) CT examination protocols. Materials and methods The X-ray beam quality was determined by measuring the half-value layer (HVL) and calculating the mean weighted energy for 100, 120, 150 kVp (using standard filtration) and for 100 and 150 kVp using TF (Sn100 kVp and Sn150 kVp, respectively). Acquisitions were performed on a phantom at four dose levels for each previously defined kVp. The mean attenuation (NCT), noise-power-spectrum (NPS) and task-based transfer function (TTF) were computed. The detectability index (d’) was computed to model the detection of two lesions in spine and pelvic/hip examination and two for chest exploration. Image quality and detectability using a TF were assessed for two routinely used ULD protocols. Results The HVL and mean weighted energy increased using a TF for the same tube voltage. Using a TF for the same tube voltage changed NCT for bone and acrylic inserts, decreased the NPS peak without changing the NPS spatial frequency and increased the TTF values. The d’ values were improved using a TF and with the dose increase. d’ values of all modeled lesions were improved using Sn100 kVp and Sn150 kVp for the lumbar-spine/pelvis-hip and chest ULD protocols except for sclerotic bone lesion using Sn150 kVp. Conclusion The use of TF increases the X-ray beam quality and improves the image quality characteristics in phantom images, thus appearing as a promising tool for reducing dose and/or improving the image quality of ULD protocols.

International audience; Purpose: To compare the evaluation of malignant focal liver lesions (FLLs) using a semi-automated RECIST tool with a standard and an ultra-low dose (ULD) computed tomography (CT) protocol.Materials and methods: Thirty-four patients with malignant FLLs underwent two abdominal-pelvic CT examinations one using a standard protocol and one using an ULD protocol. There were 23 men and 11 women with a mean age 64.3±14.4 (SD) years (range: 22-91 years). Dosimetric indicators were recorded, and effective dose was calculated for both examinations. Mean malignant FLL attenuation, image noise and contrast-to-noise-ratio (CNR) were compared. The largest malignant FLL per patient was evaluated using the semi-automated RECIST tool to determine longest axis length, longest orthogonal axis length, volume and World Health Organisation area.Results: Dosimetric values were significantly reduced by -56% with ULD compared to standard protocol. No differences in mean malignant FLL attenuation values were found between the two protocols. Image noise was significantly increased for all locations (P

OBJECTIVES: Our objective was to determine disagreement rates in radiological reports provided by using a double-reading protocol in a national teleradiology company. METHODS: From January 2015 to July 2016, 134169 radiological exams from 36 French centers, benefited outsourced interpretations by certified radiologists, in both regular and after-hours activities. Of these, 2040 CT and MR-scans (1.5%) were subjected to a second opinion by other radiologists in the field of their anatomical specialty (cerebral, thoracic, abdominal-pelvic, and osteoarticular). A five-point agreement scale graded from 0 to 4 was assigned for each exam. Disagreements were considered as minor if no clinical consequence for patient (scores 1 and 2) and major if potential clinical consequence (score 3 and 4). Independent radiologists performed a retrospective analysis and a stratified statistical analysis. RESULTS: Double reading was performed on CT-scans (n = 934/2040, 45.8%) and MR-scans (n = 1106/2040, 54.2%) performed in regular (80.1%) and after-hours activities (19.9%). Disagreement scores occurred in 437 exams (21.4%), including major disagreements in 59 (2.9%). Among these, 48/754 were assigned by the thoracic second reader (6.4%), 6/70 by the abdominal-pelvic second reader (8.6%), 3/901 by the osteoarticular second reader (0.3%), and 2/315 by the cerebral second reader (0.6%), with statistical significant difference. No additional disagreement rate was observed in regular and after-hours activities (P = 0.63). CONCLUSIONS: Double-reading of outsourced CT and MRI interpretations yielded 21.4% disagreement rate, with potential clinical consequence for patient in 2,9% of the cases. These results are in accordance with those previously reported and suggests that quality assurance of outsourced interpretations is needed.

International audience; Objective To assess diagnostic reference levels (DRLs) in surgery for the most frequent procedures as required by the European Directive 2013/59/Euratom. Methods A survey was conducted in six centers. Eight orthopedic, urology and gastrointestinal surgical procedures were analyzed. Kerma area product (KAP) and fluoroscopy time (FT) were recorded for 50 patients (except for elbow 30 patients) per procedure and per center from September 2016 to September 2017. DRLs were calculated as the 3rd quartiles of the distributions. For shoulder surgery, DRLs were defined according to the complexity of the procedure. For hand/wrist and foot/ankle surgery, DRLs were defined according to the technology (conventional C-arm vs. mini-C-arm). Results Results of 1870 procedures were retrieved. DRLs were calculated for the two dosimetric indicators and the eight procedures. DRLs were 2130 mGy.cm2 and 1.4 min for proximal femoral intramedullary nail, 1185 mGy.cm2 and 0.9 min for laparoscopic cholecystectomy and 2195 mGy.cm2 and 1.0 min for double-J (pigtail) ureteral catheter insertion. For shoulder surgery, KAP and FT were significantly higher (p andlt; 0.05) for intramedullary procedures compared to extramedullary procedures. For hand/wrist and foot/ankle surgery, the KAPs were significantly higher (p andlt; 0.05) with conventional C-arm compared to mini-C-arm, but FTs were not significantly different (p not significant). Conclusion This study reports DRLs in surgery based on a multicentric survey. Key Points • Delivered dose in surgery depends on procedure, practice and patient. • Diagnostic reference levels (DRLs) are proposed for eight surgical procedures. • DRLs are useful to benchmark practices and optimize protocols. © 2018, European Society of Radiology.

Objective: In this study, we aimed to analyze technical and diagnostic potential, and safety of the small-caliber vacuum-assisted biopsy (SCVAB) device in a multicenter consecutive study taking into consideration the type and location of breast lesion. Methods: We collected data from 5 breast imaging centers where radiologists used the SCVAB device for biopsies in 162 patients. We analyzed the conditions for using the SCVAB device according to the characteristics of the lesions, the volume of excision, and the analyzability obtained by biopsy samples. Results: The biopsies of 80 circumscribed masses, 61 complex lesions, and 24 microcalcification foci were included in the study. The reasons for choosing SCVAB as an initial technique were identified. A total of 47 lesions were removed with SCVAB; among them, 24 lesions were initially chosen for total excision. SCVAB was used as a second-choice biopsy method after core-needle biopsy failure in 20 cases. If SCVAB had not been available, vacuum-assisted biopsy would have been the most frequently used technique (106 under ultrasound, and 18 under stereotactical guidance). Conclusions: The SCVAB system is an alternative to classical vacuum biopsy, enabling representative samples to be obtained from lesions that are difficult to access, complex, small, or in cases of unsuccessful previous biopsy. The SCVAB system was determined as the chosen technique by the radiologists in this study due to feasibility, ergonomics and absence of side effects detected in this study.

International audience; PURPOSE: To assess the value of the routine use of radiochromic films in abdominopelvic embolization procedures to improve patient follow-up. METHODS: A total of 55~patients who underwent transcatheter abdominopelvic embolization were prospectively included. Six types of procedures were evaluated including hepatic chemoembolization (HCE), gonadal veins embolization (GVE), uterine elective embolization (UEE), uterine urgent embolization (UUE), abdominal elective embolization (AEE), and abdominal urgent embolization (AUE). Dosimetric indicators (DIs) such as air-kerma (AK) and kerma-area-product (KAP) were collected and peak skin dose (PSD) was measured with radiochromic films. Correlations between PSD and DIs were searched for. RESULTS: The mean (\textpmstandard deviation [SD]) PSD for the various procedures were: 1033\textpm502~mGy for HCE; 476\textpm271~mGy for GVE; 460\textpm171 mGy for UEE; 531\textpm263~mGy for UUE; 708\textpm896~mGy for AEE; 683\textpm392~mGy for AUE. Strong correlations were observed between PSD and DIs (r=0.974 for AK and r=0.925 for KAP). PSD was\textgreater2Gy in one procedure and all procedures (7/132) procedures resulted in AK\textgreater2Gy, mostly for HCE and AEE. CONCLUSION: Dosimetry using radiochromic film is only appropriate for HCE, AEE and AUE, whereas dose-mapping systems present a more suitable solution for all embolizations including those with AK that occasionally exceed 2Gy.

International audience; Purpose: The second edition of the artificial intelligence (AI) data challenge was organized by the French Society of Radiology with the aim to: (i), work on relevant public health issues; (ii), build large, mul-ticentre, high quality databases; and (iii), include three-dimensional (3D) information and prognostic questions. Materials and methods: Relevant clinical questions were proposed by French subspecialty colleges of radiology. Their feasibility was assessed by experts in the field of AI. A dedicated platform was set up for inclusion centers to safely upload their anonymized examinations in compliance with general data protection regulation. The quality of the database was checked by experts weekly with annotations performed by radiologists. Multidisciplinary teams competed between September 11 th and October 13 th 2019. Results: Three questions were selected using different imaging and evaluation modalities, including: pulmonary nodule detection and classification from 3D computed tomography (CT), prediction of expanded disability status scale in multiple sclerosis using 3D magnetic resonance imaging (MRI) and segmentation of muscular surface for sarcopenia estimation from two-dimensional CT. A total of 4347 examinations were gathered of which only 6% were excluded. Three independent databases from 24 individual centers were created. A total of 143 participants were split into 20 multidisciplinary teams. Conclusion: Three data challenges with over 1200 general data protection regulation compliant CT or MRI examinations each were organized. Future challenges should be made with more complex situations combining histopathological or genetic information to resemble real life situations faced by radiologists in routine practice.

International audience; Purpose: To compare the noise-magnitude and noise-texture obtained using strong kernel across two generations of iterative reconstruction (IR) algorithms proposed by three manufacturers.Materials and methods: Five computed tomography (CT) systems equipped with two generations of IR algorithm (hybrid/statistical IR [H/SIR] or full/partial model-based IR [MBIR]) were compared. Acquisitions on Catphan 600 phantom were performed at 120kV and three dose levels (CTDIvol: 3, 7 and 12mGy). Raw data were reconstructed using standard "bone" kernel for filtered back projection and one iterative level of two generations of IR algorithms. Contrast-to-noise ratio (CNR) was computed using three regions of interest placed semi-automatically: two placed in the low-density polyethylene and Teflon inserts and another placed on the solid water. Noise power spectrum (NPS) was computed to assess the NPS-peak and noise-texture.Results: CNR was significantly greater in MBIR compared to H/SIR algorithms for all CT systems (P

Purpose To determine the lowest suitable dose level for the detection of pulmonary arteriovenous malformation (PAVM) using a task-based image quality assessment. Material and methods A phantom was scanned using the standard chest protocol (STD) and 4 other ultra-low dose protocols (ULD) using various kVp. Raw data were reconstructed using level 5 of the hybrid iterative reconstruction algorithm (iDose4) for the STD protocol, and level 6 of iDose4 and levels 1 to 3 of model-based iterative reconstruction (IMR) for the ULD protocols. Both quantitative criteria and qualitative analysis were used to compare protocols. Noise-power-spectrum and Task-based transfer function were computed using imQuest software. The detectability-index (d’) was computed for the detection of PAVM. A subjective analysis was performed by 2 chest radiologists to validate the image-quality obtained on the anthropomorphic phantom for all protocols. Results Similar d’ values were found for ULD-140 using iDose4 6 compared to STD protocol. Greater d’ values were found for all ULD protocols using IMR compared to STD. Subjective image quality was rated as acceptable to excellent for ULD-140 and ULD-120 for all reconstruction types, for ULD-100 and ULD-80 using IMR2, and for ULD-100 using IMR1. Image smoothing was poor for IMR3 for ULD-100 and ULD-80. Finally, the ULD-80 protocol reconstructed with IMR2 was chosen for the detection of PAVM. With this protocol, the dose (CTDIvol of 0.3 mGy) was reduced by 91% compared with the STD protocol. Conclusion A dose level as low as 0.3 mGy reconstructed with IMR2 provides an image quality suitable for the detection of PAVM.

International audience; Introduction: Cone-beam computed tomography (CBCT) has been developed to improve reliability of many interventional radiology (IR) procedures performed with Angio system, such as transarterial chemoembolization (TACE). Angio-CT has emerged as a new imaging technology that combines a CT scanner with an Angio system in the same IR suite. The purpose of our study was to compare Angio system with CBCT capability and Angio-CT in terms of patient radiation exposure during TACE procedures.Materials and methods: Consecutive TACE procedures performed between January 2016 and September 2017 with the two imaging modalities (Artis Zeego defining the CBCT group and Infinix-i 4D-CT defining the Angio-CT group) were reviewed. TACE and patient's characteristics and patient radiation exposure parameters were collected. Dose-area products (DAP) and dose-length products (DLP) were converted into effective doses (ED) using conversion factors. Accuracy of tumor targeting and response was retrospectively assessed.Results: A total of 114 TACE procedures in 96 patients were included with 57 procedures in each group. The total ED in the Angio-CT group was 2.5 times lower than that in the CBCT group (median 15.4 vs. 39.2 mSv, p < 0.001). Both 2D ED and 3D ED were lower in the Angio-CT group than in the CBCT group (5.1 vs. 20 mSv, p < 0.001, and 7.4 vs. 17.9 mSv, p < 0.001, respectively). There was no significant difference neither in terms of classes of tumor targeting (p = 0.509) nor in terms of classes of tumor response (p = 0.070) between both groups.Conclusion: Angio-CT provides significant decrease in patient effective dose during TACE procedures compared to Angio system with CBCT.

International audience; Objective: To assess the interactive Skin Dose Map® tool (SDMTool) integrated to the radiation dose management system (RDMS) DoseWatch® with Gafchromic® films for implementation in routine practice.Methods: A retrospective dose estimation software SDMTool was used to calculate Peak Skin Dose (PSD) and display the patient skin dose distribution. PSD was calculated with a triangle mesh of 0.055 cm2 resolution on ICRP 110 male anthropomorphic phantom and with a square ROI of 1 cm2 on flat phantom. The tool uses Radiation Dose Structured Reports (RDSR) data to model exposure events and calculate the PSD per event. The PSD and the skin dose distribution estimated with SDMTool were evaluated in comparison with Gafchromic® films positioned under the PMMA phantom (20 cm) for 13 configurations. Measurements were performed on a Philips system. Statistical analysis were carried out to compare PSDFilm and PSDSDM.Results: Average differences between PSDFilm and PSDSDM were 6% ± 6% (range from -3% to 22%) for flat phantom and 5% ± 7% (range from -3% to 25%) for ICRP phantom. Concordance was good between the measured PSDFilm and the estimated PSDSDM with Lin's coefficient estimation and 95% Confidence Interval of 0.979 [0.875; 0.984] for flat phantom and 0.977 [0.877; 0.985] for ICRP phantom. Dose map representations are concordant for 11 of the 13 tests on PMMA phantom. Disparities arose from the limitations of the RSDR format: table displacement during fluoroscopy events and the use of wedge filter.Conclusion: The results found in this experimental evaluation show that the SDMTool is a suitable alternative to Gafchromic® film to calculate PSD.

Purpose The purpose of this study was to evaluate a cooperation program in order to compare incidence of complications after peripherally inserted central catheter (PICC) placement between radiologists and technicians. Materials and methods PICC placement technique was standardized with ultrasound-guided puncture and fluoroscopic guidance. Numbers of PICC delegated to technicians, and PICC placement difficulties, were prospectively recorded for the whole study population whereas complications such as PICC infection, deep venous thrombosis and catheter occlusion were prospectively recorded until PICC removal for a subgroup of patients included during one month. Results A total of 722 patients had PICC placement. There were 382 men and 340 women with a mean age of 66.8 ± 15.8 (SD) years (range: 18–94 years); of these, 442/722 patients (61.22%) were included in the cooperation program with 433/722 patients (59.97%) who effectively had PICC placement by technicians and 289/722 (40.03%) by radiologists. Technicians needed radiologists’ help for 23/442 patients (5.20%) including 6 failed PICC placement subsequently performed by radiologists. Twenty complications (20/77; 26%) were recorded in the subgroup of 77 patients studied for complications. No differences in complications rate were found between the 33 patients who underwent PICC placement by radiologists (6/33; 18%) and the 44 patients who underwent PICC placement by technicians (14/44; 32%) (P = 0.296). Complications included 8 PICC-related infections (8/77; 10.4%), 3 deep venous thromboses (3/77; 3.9%) and 9 catheter occlusions (9/77; 11.7%). Conclusion PICC placement led by technicians is feasible and safe without statistical difference in terms of complications compared to PICC placement made by radiologists.

International audience; Tumors and tumor-like lesions of the knee are common conditions. Because the synovial membrane covers a large part of the knee, tumors and tumor-like lesions of the knee are mostly synovial. Magnetic resonance imaging (MRI) plays a major role in the assessment and characterization of these lesions. However, the diagnostic approach of these lesions must be performed systematically. First, the lesion must be precisely located, and then the anatomical structure involved must be determined. Finally, clinical background that includes the age of the patient, frequency of the disease and, if any, associated signs as well as MRI characteristics must be analyzed. In this review, we describe the anatomy of the knee and its compartments and provide a description of the main tumors and tumor-like lesions of the knee. We present a diagnostic approach based on the location within the knee of the lesions and the anatomical structures involved.

The main objective of this study was to investigate the impact of implementing a computer-based order entry system without clinical decision support on the number of radiographs ordered for patients seen in the emergency department.Our results show a decrease in the number of radiographs ordered after computer-based order entry system implementation, despite an increase in the number of emergency department admissions.Our study also shows that the time interval between emergency department admission and medical imaging was not affected by this new workflow. Background and objectiveThe adoption of computerized physician order entry is an important cornerstone of using health information technology (HIT) in health care. The transition from paper to computer forms presents a change in physicians' practices. The main objective of this study was to investigate the impact of implementing a computer-based order entry (CPOE) system without clinical decision support on the number of radiographs ordered for patients admitted in the emergency department. MethodsThis single-center pre-/post-intervention study was conducted in January, 2013 (before CPOE period) and January, 2014 (after CPOE period) at the emergency department at Nimes University Hospital. All patients admitted in the emergency department who had undergone medical imaging were included in the study. ResultsEmergency department admissions have increased since the implementation of CPOE (5388 in the period before CPOE implementation vs. 5808 patients after CPOE implementation, p=.008). In the period before CPOE implementation, 2345 patients (44%) had undergone medical imaging; in the period after CPOE implementation, 2306 patients (40%) had undergone medical imaging (p=.008). In the period before CPOE, 2916 medical imaging procedures were ordered; in the period after CPOE, 2876 medical imaging procedures were ordered (p=.006). In the period before CPOE, 1885 radiographs were ordered; in the period after CPOE, 1776 radiographs were ordered (p

International audience; PURPOSE:To evaluate the impact of Automatic Exposure Control (AEC) on radiation dose and image quality in paediatric chest scans (MDCT), with or without iterative reconstruction (IR).METHODS:Three anthropomorphic phantoms representing children aged one, five and 10-year-old were explored using AEC system (CARE Dose 4D) with five modulation strength options. For each phantom, six acquisitions were carried out: one with fixed mAs (without AEC) and five each with different modulation strength. Raw data were reconstructed with Filtered Back Projection (FBP) and with two distinct levels of IR using soft and strong kernels. Dose reduction and image quality indices (Noise, SNR, CNR) were measured in lung and soft tissues. Noise Power Spectrum (NPS) was evaluated with a Catphan 600 phantom.RESULTS:The use of AEC produced a significant dose reduction (p

Objectives To evaluate the distortion of circular structures induced by the increased image noise related to dose reduction and to assess the effect of iterative reconstruction (IR). Methods MDCT acquisitions were performed with 120 kVp for 200/100/60/40/20 mAs with 100%/50%/30%/20%/10% of dose. Raw data were reconstructed by filtered back projection (FBP) and with two IR strengths. Image quality indices referred to water and acrylic were measured on a quality image phantom. Areas, perimeters, circularity were measured on the circular inserts of 4.8, 7.9 and 11.1 mm on a morphological phantom. Results Dose reduction resulted in increased image noise and in decreased signal to noise ratio and contrast to noise ratio. IR improved these indices for the same dose without affecting the signal (number CT) and spatial resolution (modulation transfer function). The values of area, perimeter and circularity were altered compared to the actual value and the inserts were visually deformed with the dose reduction. IR improved these three parameters. Image quality indices, areas, perimeters and circularity of inserts were similar between the acquisition at 100% of the dose in FBP, 50% in strength-3 and 30% in strength-5 with different curves of noise power spectrum. Conclusion IR associated to 70% of dose reduction modifies the images smooth (NPS) but maintains adequate image quality indices without causing distortions of circular structures.

International audience; Purpose: To compare the noise-magnitude and noise-texture across two generations of iterative reconstruction (IR) algorithms proposed by three manufacturers according to the dose level. Materials and methods: Five computed tomography (CT) systems equipped with two generations of IR algorithms (hybrid/statistical IR [H/SIR] or full/partial model-based IR [MBIR]) were compared. Acquisitions on Catphan 600 phantom were performed at 120kV and three dose levels (3-, 7- and 12-mGy). Raw data were reconstructed using standard "soft tissue" kernel for filtered back projection and one iterative level of two generations of IR algorithms. Contrast to-noise-ratio (CNR) was computed using three regions of interest: two of them placed in the low-density polyethylene (LDPE) and Teflon® inserts and another placed on the solid water. Noise power spectrum (NPS) was computed to assess the noise-magnitude (NPS peak) and noise-texture (NPS spatial frequency). Results: CNR increased significantly in MBIR compared to H/SIR algorithms for General-Electric (GE) Healthcare (45%±12 [SD]) and Philips Healthcare systems (62%±11 [SD]) (P

International audience; Purpose To compare metallic artifact reduction (MAR) algorithms proposed by four vendors according to the delivered dose and iterative level using a phantom study. Methods Four CT systems (Revolution GSI®, Ingenuity Elite®, Somatom Edge®, and Aquilion Prime®) equipped with MAR algorithms (Smart MAR®, O-MAR®, iMAR®, and SEMAR®) were compared. Acquisitions were performed with CIRS model 062M Phantom containing a titanium rod core insert using 120 kV and two dose levels (3 and 7 mGy). Images were reconstructed with and without MAR algorithms using standard “soft tissue” kernel for filtered back projection (FBP) and intermediary iterative level. Artifact propagation was assessed by counting the number of pixels containing a HU outside a defined threshold interval (> 100HU and < −80 HU). Artifact correction was evaluated by computing the differences between images with and without MAR. Results Accuracy of NCT values increased significantly using MAR algorithms, IR, and high dose levels (P < 0.001). Image noise reduced −31 ± 15 (SD) % (range: −50%;−14%) with Smart-MAR®, −28 ± 3 (SD) % (range −31%; −25%) with O-MAR®, −32 ± 7 (SD) % (range: −40%; −24%) with iMARCN®, −52 ± 8 (SD) % (range: −60%; −42%) with iMARTH® and −29 ± 6 (SD) % (range: −37%; −23%) with SEMAR®. The number of pixels outside the threshold interval was also reduced using MAR algorithms. Each MAR algorithm corrected in distinct patterns, with satisfactory artifact correction for all MAR algorithms. Conclusion This study demonstrates that artifact correction using MAR algorithms differs according to the main manufacturers, although corrections are satisfactory for all systems. Corrections also improved by using IR and increasing the dose level.

International audience

Objective Pelvic fractures represent 5% of all traumatic fractures and 30% are isolated pelvic fractures. Pelvic fractures are found in 10 to 20% of severe trauma patients and their presence is highly correlated to increasing trauma severity scores. The high mortality of pelvic trauma, about 8 to 15%, is related to actively bleeding pelvic injuries and/or associated injuries to the head, abdomen or chest. Regardless of the severity of pelvic trauma, diagnosis and treatment must proceed according to a strategy that does not delay the management of the most severely injured patients. To date, in France, there are no guidelines issued by healthcare authorities or professional societies that address this subject. Design A consensus committee of 22 experts from the French Society of Anaesthesia and Intensive Care Medicine (Societe Francaise d’Anesthesie et de Reanimation; SFAR) and the French Society of Emergency Medicine (Societe Francaise de Medecine d’Urgence; SFMU) in collaboration with the French Society of Radiology (Societe Francaise de Radiologie; SFR), French Defence Health Service (Service de Sante des Armees; SSA), French Society of Urology (Association Francaise d’Urologie; AFU), the French Society of Orthopaedic and Trauma Surgery (Societe Francaise de Chirurgie Orthopedique et Traumatologique; SOCFCOT), and the French Society of Digestive Surgery (Societe Francaise de Chirurgie digestive; SFCD) was convened. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently from any industry funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. Methods Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. The analysis of the literature and the recommendations were then conducted according to the GRADE® methodology. Results The SFAR Guideline panel provided 22 statements on prehospital and hospital management of the unstable patient with pelvic fracture. After three rounds of discussion and various amendments, a strong agreement was reached for 100% of recommendations. Of these recommendations, 11 have a high level of evidence (Grade 1 ± ), 11 have a low level of evidence (Grade 2 ± ). Conclusions Substantial agreement exists among experts regarding many strong recommendations for management of the unstable patient with pelvic fracture.

The original version of this article, published on 01 August 2018, unfortunately contained two mistakes.

Objectives To create an adaptable and global approach for optimizing MDCT protocols by evaluating the influence of acquisition parameters and Iterative Reconstruction (IR) on dose reduction and image quality. Materials and methods MDCT acquisitions were performed on quality image phantom by varying kVp, mAs, and pitch for the same collimation. The raw data were reconstructed by FBP and Sinogram Affirmed Iterative Reconstruction (SAFIRE) with different reconstruction kernel and thickness. A total of 4032 combinations of parameters were obtained. Indices of quality image (image noise, NCT, CNR, SNR, NPS and MTF) were analyzed. We developed a software in order to facilitate the optimization between dose reduction and image quality. Its outcomes were verified on an adult anthropomorphic phantom. Results Dose reduction resulted in the increase of image noise and the decrease of SNR and CNR. The use of IR improved these indices for the same dose without affecting NCT and MTF. The image validation was performed by the anthropomorphic phantom. The software proposed combinations of parameters to reduce doses while keeping indices of the image quality adequate. We observed a CTDIvol reduction between −44% and −83% as compared to the French diagnostic reference levels (DRL) for different anatomical localization. Conclusion The software developed in this study may help radiologists in selecting adequate combinations of parameters that allows to obtain an appropriate image with dose reduction.

International audience; PURPOSE: The purpose of this study was to evaluate and compare the diagnostic accuracy of ultra-low dose (ULD) computed tomography (CT) with that of standard dose (STD) CT in the detection and characterization of focal liver lesions in neoplastic patients. MATERIALS AND METHODS: A total of 177 neoplastic patients who underwent two abdominopelvic CT examinations (one with STD and one with ULD protocol) for suspected focal liver lesions were included. There were 103 men and 74 women with a mean age of 64.6\textpm14.4 (SD) (range: 19-93 years). Raw data images were reconstructed with iterative reconstruction. Dose length product (DLP) and effective dose for both protocols were compared. Images were independently evaluated by two radiologists for image-quality, diagnostic quality, and confidence level. RESULTS: DLP for STD and ULD were respectively 215.4\textpm92.0 (SD) mGy\textperiodcenteredcm (range: 76-599mGy\textperiodcenteredcm) and 90.7\textpm37.2 (SD) mGy\textperiodcenteredcm (range: 32-254mGy\textperiodcenteredcm). Effective dose for STD and ULD CT were 3.2\textpm1.4 (SD) mSv (range: 1.1-9.0mSv) and 1.4\textpm0.6 (SD) mSv (range: 0.5 to 3.8mSv). A significant 58% dose reduction was found between the two protocols (P\textless0.05). Noise, signal-to-noise ratio and contrast-to-noise ratio were higher with the ULD protocol compared to the STD protocol. No differences in subjective image quality were found between the two protocols. STD CT revealed focal liver lesions in 80 patients and ULD CT in 70 patients (P\textless0.05). ULD protocol resulted in a sensitivity of 83.8% and a specificity of 96.9% for the diagnosis of focal liver lesions although it was not able to characterize them properly (Se 62.5%). CONCLUSION: STD CT helps detect and characterize focal liver lesions. ULD CT offers good performance to detect focal liver lesions but with lower performances for lesion characterization.

International audience; To study the effect of patient size, anatomical location and modulation strength (MS) on image-quality and delivered dose of CT scans acquired with automatic-exposure-control system (AEC). Four anthropomorphic phantoms (three paediatric and one thin adult) were studied, and normal and obese adults were simulated by placing bolus plates around the adult phantom. Thorax and abdomen-pelvis CT were performed using an AEC system equipped with five possible MS. Modulated tube current (mAsmod) was compared to Reference mAs and image-noise was assessed. Effective-mAs were lower than Reference-mAs for all but the obese phantom. However, reversal points were estimated for an effective diameter of 27.8 cm in thorax and 26.9 cm in abdomen-pelvis scans, beyond which the patterns of MS were inversed. mAsmod were dependent on attenuation differences among distinct anatomical location. Finally, dose delivered was associated to the mAsmod and patient's size, with both affecting image-quality.