A survey among the members of European Society of Radiology (ESR) was conducted regarding the current practical clinical experience of radiologists with Artificial Intelligence (AI)-powered tools. 690 radiologists completed the survey. Among these were 276 radiologists from 229 institutions in 32 countries who had practical clinical experience with an AI-based algorithm and formed the basis of this study. The respondents with clinical AI experience included 143 radiologists (52%) from academic institutions, 102 radiologists (37%) from regional hospitals, and 31 radiologists (11%) from private practice. The use case scenarios of the AI algorithm were mainly related to diagnostic interpretation, image post-processing, and prioritisation of workflow. Technical difficulties with integration of AI-based tools into the workflow were experienced by only 49 respondents (17.8%). Of 185 radiologists who used AI-based algorithms for diagnostic purposes, 140 (75.7%) considered the results of the algorithms generally reliable. The use of a diagnostic algorithm was mentioned in the report by 64 respondents (34.6%) and disclosed to patients by 32 (17.3%). Only 42 (22.7%) experienced a significant reduction of their workload, whereas 129 (69.8%) found that there was no such effect. Of 111 respondents who used AI-based algorithms for clinical workflow prioritisation, 26 (23.4%) considered algorithms to be very helpful for reducing the workload of the medical staff whereas the others found them only moderately helpful (62.2%) or not helpful at all (14.4%). Only 92 (13.3%) of the total 690 respondents indicated that they had intentions to acquire AI tools. In summary, although the assistance of AI algorithms was found to be reliable for different use case scenarios, the majority of radiologists experienced no reduction of practical clinical workload.
The purpose of this study was to develop micron-sized droplet emulsions able to increase the heat deposition of high intensity focused ultrasound (HIFU), aiming to accelerate the tumour ablation in highly perfused organs with reduced side effects. The investigated droplets consisted of a perfluorooctyl bromide (PFOB) core coated with a biocompatible fluorinated surfactant called F-TAC. The novelty of this work relies on the use, for this application, of a high boiling point perfluorocarbon core (142 °C), combined with an in-house fluorinated surfactant to formulate the emulsion, yielding quasi-reversible strong interactions between the HIFU beam and the droplets. In order to fine-tune the emulsion size, surfactants with different hydrophobic/hydrophilic ratios were screened. Different concentrations of PFOB droplets were homogeneously embedded in two different MRI compatible materials, exhibiting either ultrasound (US) absorbing or non-absorbing properties. For the US absorbing TMM, the speed of sound at each droplet concentration was also assessed. These TMM were sonicated by 1 MHz HIFU with acoustical power of 94 W at two different duty cycles. The temperature elevation was monitored accurately by MRI proton shift resonance frequency in near real-time. The presence of sono-sensitive droplets induced a significant increase of the HIFU thermal effect that persisted under repeated sonication of the same locus. Optimal enhancement was observed at the lowest concentration tested (0.1%) with an additional temperature rise at the focal point of approximately 4 °C per applied kJ of acoustic energy corresponding to one order of magnitude augmentation of the thermal dose. Furthermore, no deformation of the heating pattern pre- or post-focal was observed.
To compare 2 incompatible generations of iterative reconstructions from the same raw dataset based on automatic emphysema quantification and noise reduction: a hybrid algorithm called sinogram affirmed iterative reconstruction (SAFIRE) versus a model-based algorithm called advanced modeled iterative reconstruction (ADMIRE). Raw datasets of 40 non-contrast thoracic computed tomography scanners obtained from a single acquisition on a SOMATOM Definition Flash unit (Siemens Healthcare, Forchheim) were reconstructed with 3 levels of SAFIRE and ADMIRE algorithms resulting in a total of 240 datasets. Emphysema index (EI) and image noise were compared using repeated analysis of variance (ANOVA) analysis with a P value <.05 considered statistically significant. EI and image noise were stable between both generations of IR when reconstructed with the same level (P >= 0.31 and P >= 0.06, respectively). SAFIRE and ADMIRE perform equally in terms of emphysema quantification and noise reduction.
Objective. To compare radiation dose and image quality of thoracoabdominal scans obtained with a high-pitch protocol (pitch 3.2) and iterative reconstruction (Sinogram Affirmed Iterative Reconstruction) in comparison to standard pitch reconstructed with filtered back projection (FBP) using dual source CT. Methods: 114 CT scans (Somatom Definition Flash, Siemens Healthineers, Erlangen, Germany), 39 thoracic scans, 54 thoracoabdominal scans and 21 abdominal scans were performed. Analysis of three protocols was undertaken; pitch of 1 reconstructed with FBP, pitch of 3.2 reconstructed with SAFIRE, pitch of 3.2 with stellar detectors reconstructed with SAFIRE. Objective and subjective image analysis were performed. Dose differences of the protocols used were compared. Results: Dose was reduced when comparing scans with a pitch of 1 reconstructed with FBP to high-pitch scans with a pitch of 3.2 reconstructed with SAFIRE with a reduction of volume CT dose index of 75% for thoracic scans, 64% for thoracoabdominal scans and 67% for abdominal scans. There was a further reduction after the implementation of stellar detectors reflected in a reduction of 36% of the dose-length product for thoracic scans. This was not at the detriment of image quality, contrast-to-noise ratio, signal-to-noise ratio and the qualitative image analysis revealed a superior image quality in the high-pitch protocols. Conclusion: The combination of a high pitch protocol with iterative reconstruction allows significant dose reduction in routine chest and abdominal scans whilst maintaining or improving diagnostic image quality, with a further reduction in thoracic scans with stellar detectors. Advances in knowledge: High pitch imaging with iterative reconstruction is a tool that can be used to reduce dose without sacrificing image quality.
The diagnosis of pneumonia is challenging. Our objective was to assess whether low-dose computed tomography (LDCT) modified the probability of diagnosing pneumonia in elderly patients.We prospectively included patients aged over 65 years with a suspicion of pneumonia treated with antimicrobial therapy (AT). All patients had a chest radiograph and LDCT within 72 h of inclusion. The treating clinician assessed the probability of pneumonia before and after the LDCT scan using a Likert scale. An adjudication committee retrospectively rated the probability of pneumonia and was considered as the reference for diagnosis. The main outcome was the difference in the clinician's pneumonia probability estimates before and after LDCT and the proportion of modified diagnoses which matched the reference diagnosis (the net reclassification improvement (NRI)).A total of 200 patients with a median age of 84 years were included. After LDCT, the estimated probability of pneumonia changed in 90 patients (45%), of which 60 (30%) were downgraded and 30 (15%) were upgraded. The NRI was 8% (NRI event (-6%) + NRI non-event (14%)).LDCT modified the estimated probability of pneumonia in a substantial proportion of patients. It mostly helped to exclude a diagnosis of pneumonia and hence to reduce unnecessary AT.
To evaluate the safety and efficacy of ethylene vinyl alcohol copolymer (EVOH) injection for selective occlusion of portal branches considered at risk for non-target embolisation during preoperative portal vein embolisation (PVE).
Objective: High intensity focused ultrasound (HIFU) treatment in the abdominal cavity is challenging due to the respiratory motion. In the self-scanning HIFU ablation method, the focal spot is kept static and the heating pattern is obtained through natural tissue motion. This paper describes a novel approach for modulating the HIFU power during self-scanning in order to compensate for the effect of tissue motion on thermal buildup. Methods: The therapy, using hybrid ultrasound (US)/magnetic resonance (MR) imaging, consists of detecting and tracking speckle on US images in order to predict the next tissue position, and modulating the HIFU power according to the tissue speed in order to obtain a rectilinear pattern of uniform temperature elevation. Experiments were conducted on ex vivo tissue subjected to a breathing-like motion generated by an MR-compatible robot and sonicated by a phased array HIFU transducer. Results: US and MR data were free from interferences. For both periodic and non-periodic motion, MR temperature maps showed a substantial improvement in the uniformity of the temperature elevation by using acoustic power modulation. Conclusion: The presented method does not require a learning stage and enables a duty cycle close to 100%, higher average acoustic intensity and avoidance of side lobe effects versus performing HIFU beam steering to compensate tissue motion. Significance: To our knowledge, the proposed method provides the first experimental validation of the self-scanning HIFU ablation paradigm via a real-time hybrid MRI/US imaging, opening the path toward self-scanning in vivo therapies.
This work provides detailed estimates of the foetal dose from diagnostic CT imaging of pregnant patients to enable the assessment of the diagnostic benefits considering the associated radiation risks.
To determine the diagnostic performance of FDG-PET/MRI with diffusion-weighted imaging (FDG-PET/DWIMRI) for detection and local staging of head and neck squamous cell carcinoma (HNSCC) after radio(chemo)therapy.
To determine if radiation dose delivered by contrast-enhanced CT (CECT) for acute abdominal pain can be reduced to the dose administered in abdominal radiography (<2.5 mSv) using low-dose CT (LDCT) with iterative reconstruction algorithms.
Asymptomatic spontaneous nephrocutaneous fistula is a rare and severe complication of chronic urolithiasis. We report a case of 56-year-old woman with a nephrocutaneous fistula (NFC) which developed from a superinfected urinoma following calyceal rupture due to an obstructing calculus in the left ureter. The patient was clinically asymptomatic and came to the emergency department for a painless left flank fluctuating mass. This urinoma was superinfected, with a delayed development of renal abscesses and perirenal phlegmon found on contrast-enhanced uro-computed tomography (CT), responsible for left renal vein thrombophlebitis and left psoas abscess. Thereafter, a 99 mTc dimercaptosuccinic acid (DMSA) scintigraphy revealed a nonfunctional left kidney, leading to the decision of left nephrectomy. Chronic urolithiasis complications are rare and only few cases are reported in medical literature. A systematic medical approach helped selecting the best imaging modality to help diagnosis and treatment. Indeed, uro-CT scan and renal scintigraphy with 99 mTc-DMSA are the most sensitive imaging modalities to investigate morphological and functional urinary tract consequences of NFC, secondary to chronic urolithiasis.
To compare two fat suppression techniques used for 3D T1-weighted sequence in breast MRI (magnetic resonance imaging), namely Dixon versus spectral fat saturation (fat sat).
Purpose Treatments using high‐intensity focused ultrasound (HIFU) in the abdominal region remain challenging as a result of respiratory organ motion. A novel method is described here to achieve 3D motion‐compensated ultrasound (US) MR‐guided HIFU therapy using simultaneous ultrasound and MRI. Methods A truly hybrid US‐MR‐guided HIFU method was used to plan and control the treatment. Two‐dimensional ultrasound was used in real time to enable tracking of the motion in the coronal plane, whereas an MR pencil‐beam navigator was used to detect anterior–posterior motion. Prospective motion compensation of proton resonance frequency shift (PRFS) thermometry and HIFU electronic beam steering were achieved. Results The 3D prospective motion‐corrected PRFS temperature maps showed reduced intrascan ghosting artifacts, a high signal‐to‐noise ratio, and low geometric distortion. The k‐space data yielded a consistent temperature‐dependent PRFS effect, matching the gold standard thermometry within approximately 1°C. The maximum in‐plane temperature elevation ex vivo was improved by a factor of 2. Baseline thermometry acquired in volunteers indicated reduction of residual motion, together with an accuracy/precision of near‐harmonic referenceless PRFS thermometry on the order of 0.5/1.0°C. Conclusions Hybrid US‐MR‐guided HIFU ablation with 3D motion compensation was demonstrated ex vivo together with a stable referenceless PRFS thermometry baseline in healthy volunteer liver acquisitions. Magn Reson Med 79:2511–2523, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
AIM:To evaluate the image quality of hepatic multidetector computed tomography (MDCT) with dynamic contrast enhancement.METHODS:It uses iodixanol 270 mg/mL (Visipaque 270) and 80 kVp acquisitions reconstructed with sinogram affirmed iterative reconstruction (SAFIRE(®)) in comparison with a standard MDCT protocol. Fifty-three consecutive patients with known or suspected hepatocellular carcinoma underwent 55 CT examinations, with two different four-phase CT protocols. The first group of 30 patients underwent a standard 120 kVp acquisition after injection of Iohexol 350 mg/mL (Accupaque 350(®)) and reconstructed with filtered back projection. The second group of 25 patients underwent a dual-energy CT at 80-140 kVp with iodixanol 270. The 80 kVp component of the second group was reconstructed iteratively (SAFIRE(®)-Siemens). All hyperdense and hypodense hepatic lesions ≥ 5 mm were identified with both protocols. Aorta and portal vessels/liver parenchyma contrast to noise ratio (CNR) in arterial phase, hypervascular lesion/liver parenchyma CNR in arterial phase, hypodense lesion/liver parenchyma CNR in portal and late phase were calculated in both groups.RESULTS:Aorta/liver and focal lesions altogether/liver CNR were higher for the second protocol (P = 0.0078 and 0.0346). Hypervascular lesions/liver CNR was not statistically different (P = 0.86). Hypodense lesion/liver CNR in the portal phase was significantly higher for the second group (P = 0.0107). Hypodense lesion/liver CNR in the late phase was the same for both groups (P = 0.9926).CONCLUSION:MDCT imaging with 80 kVp with iterative reconstruction and iodixanol 270 yields equal or even better image quality.
To prospectively evaluate the impact of iterative reconstruction (IR) algorithms on pulmonary emphysema assessment as compared to filtered back projection (FBP).
To evaluate the performance of 18F-fluorodeoxyglucose (FDG) positron emission tomography magnetic resonance imaging (PET/MR) for preoperative breast cancer staging.
The recent implementation of the dual energy technology on CT-scanners has opened new perspectives in tissue and material characterization. This study aims to evaluate whether dual energy CT can be used to assess the concentration of cocaine of intra-intestinal illegal packets.
To evaluate the prognostic value of abdominal computed tomography (CT) in patients with alcoholic hepatitis (AH).
Objectives: To study the image quality of ECG-gated-computed tomography (CT) acquisition with a high pitch CT imaging for the exploration of both the aorta and coronary arteries.Methods: Eighty-four patients underwent high-pitch ECG-gated aortic CT without beta-blockers with iterative reconstruction algorithms. Contrast-to-noise ratio (CNR) between vessels and adjacent perivascular fat tissue were calculated on the aorta and the coronary arteries. Dose-length-products (DLP) were recorded. Two blinded readers graded image quality of the aorta and the coronary arteries on a 3 point scale. Coronary artery stenoses were compared with coronary angiograms in 24 patients. Kappa values were calculated.Results: High-pitch acquisition resulted in a mean DLP of 234 +/- 93 mGy cm(4.2 mSv) for an acquisition of the entire aorta, (mean 73 +/- 16 bpm). CNR for ascending aorta was 10.6 +/- 4 and CNR for coronary arteries was 9.85 +/- 4.1. Image quality was excellent in 79/84 patients (94%), and excellent or moderate but diagnostic in 1087/1127 coronary artery segments (96%). 74 significant stenoses were observed, and 38/40 significant stenoses were confirmed by coronary angiography (K = 0.91, Sensitivity = 0.97, Specificity = 0.98).Conclusion: High-pitch ECG-gated aortic CT with iterative reconstructions allows an accurate exploration of both aorta and coronary arteries during the same acquisition, with limited dose deposition, despite the lack of beta-blockers and relatively high heart rate. Radiologists need to be aware of the necessity to analyze and report coronary artery disease in aortic examination. (C) 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.
Objectives The aim of this study was to evaluate the accuracy of preliminary computed tomography (CT) interpretations made by radiology residents in the emergency department. Methods For 4 periods of 20 consecutive days, attending radiologists prospectively recorded any disparities between their own CT interpretations (reference standard) and the preliminary interpretations of emergency radiology residents. Misinterpretations were defined as major when related to a potentially life-threatening pathology if not immediately managed after CT. The rate of disparities was calculated for all CT examinations, separately for body and neuroradiological cases, and for working and on-call hours. Results A total of 3044 emergency CT examinations were performed during the survey: 1568 (51%) body scans and 1476 (49%) neurological scans. Disparities were reported in 145 (4.8%) of all CT examinations, with 0.8% (24/3044) defined as major misinterpretations. There were 100 (6.3%) of 1568 disparities in body CT versus 45 (3.0%) of 1476 in neurological CT examinations (P = 0.001). No significant differences were found between disparities recorded during regular working hours (47/1083 [4.3%]) versus on-call hours (98/1961 [5.0%], P = 0.47). Conclusions There were typically more disparities between resident and attending interpretations in emergency body CT. Major disparities represented only a small proportion of all misinterpretations. The detailed analysis of our data enables benchmarking over time and offers a reference for optimizing the training of residents in emergency radiology.