Artificial intelligence assistance for fetal head biometry: Assessment of automated measurement software

International audienceTo evaluate the feasibility and reproducibility of artificial intelligence software (Smartplanes ®) to automatically identify the transthalamic plane from 3D ultrasound volumes and to measure the biparietal diameter (BPD) and head circumference (HC) in fetus. Material and methods: Thirty fetuses were evaluated at 17-30 weeks' gestation. For each fetus two three-dimensional (3D) volumes of the fetal head along with one conventional two-dimensional (2D) image of the transthalamic plane were prospectively acquired. The Smartplanes ® software identified the transthalamic plane from the 3D volumes and performed BPD and HC measurements automatically (3D auto). Two experienced sonographers also measured BPD and HC from 2D images and from the 3D volumes. Measurements were compared using Bland-Altman plots. Interclass correlation coefficient (ICC) was used to evaluate intraand interobserver reproducibility. Results: For each series of measurements, intra-and interobserver reproducibility rates were high with ICC values > 0.98. The 95% confidence intervals between the BPD measurements were 2 mm (3D versus 2D) and 4 mm (3D auto versus 2D) and the HC measurements were 7.5 mm (3D versus 2D) and 11 mm (3D auto versus 2D). Conclusion: Fetal head measurements obtained automatically by Smartplanes ® software from 3D volumes show good agreement with those obtained by two experienced sonographers from conventional 2D images and 3D volumes. The reproducibility of these measurements is similar to that observed by experienced sonographers

An automatic MRI quality control procedure: Multisite reports for slice thickness and geometric accuracy

International audienceIn this work, we report multi-scanner quality control monitoring using a standard and automated protocol. This magnetic resonance imaging quality control protocol, based on the American College of Radiology procedures, includes weekly scans of a dedicated phantom followed by specific measurements. The processing step commonly involves manually-performed operations which can be tedious and time-consuming hence motivating their automation. QC data were collected in four sites; data from one of them served for the validation of the automatic analysis tool. Designed as a package of MATLAB® functions, this tool was successfully validated using Student's t-test and the correlation between automatic measurements and the manual ones. Besides, the multisite QC study enabled to compare the performances of these four MR facilities. In order to avoid misinterpretation or errors in multicenter clinical studies, such approach can be recommended as a preliminary step for including a site in the studies

Évaluation des compétences pour la pratique de la biométrie échographique fœtale : validation prospective du score OSAUS METHOD

International audienceObjectivesTo develop and validate a customized variant for fetal biometry of the generic OSAUS score (Objective Structured Assessment of Ultrasound Skills)MethodsThe 5-points OSAUS METHOD grid was elaborated by defining five target skills specific to fetal biometry for each thematic item of the generic score. The level of skills of 43 trainees was prospectively assessed during an ultrasound examination by using this grid. The results of the “novice” level group (experience < 10 ultrasounds) were compared to those of the “intermediate” level group (experience ≥ 10 ultrasounds) (I). The reached/non-reached skills ratio within the different items composing the score allowed the identification of priority areas of improvement (II). Previously published distribution and actual distribution of ratings according to the generic pass/fail score were compared (III).ResultsMedian scores of “novices” (n = 29) and “intermediates” (n = 14) groups were statistically different, 1.87 (±0.75) and 3.31 (±0.83) (P = 1.85-5), respectively and corresponded to the pre-existing experience (I). A lower ratio of reached skill allowed the identification of “documentation of the examination” item as a priority area of improvement for both groups (II). The relevance of the pass/fail score is consolidated, even if an overlap was observed between novices and intermediates groups (III).ConclusionsThe relevancy and feasibility of using OSAUS scoring method for fetal biometry are supported. In addition, the possibility of comparisons with generic OSAUS remains.ObjectifsDévelopper et évaluer la pertinence clinique d’une version du score générique OSAUS (Objective Structured Assessment of Ultrasound Skills) dédiée à la biométrie fœtale.Matériel et méthodesCinq compétences cibles spécifiques à la biométrie fœtale ont été définies pour chaque item thématique du score générique permettant d’établir une grille d’évaluation OSAUS-METHOD sur 5 points (MEasurements TeacHing in Obstetrics Design). Le niveau de compétence de 43 étudiants a été évalué à l’aide grille OSAUS-METHOD (MEasurements TeacHing in Obstetrics Design) lors d’examens pratiques. Les notes des étudiants débutants (expérience pratique < 10 examens) ont été comparées à celles des étudiants de niveau intermédiaire (expérience pratique ≥ 10 examens) (I). La proportion de compétences validées ou non au sein de chacun des items thématiques du score a permis d’identifier les axes de progression prioritaires (II). La distribution des notes obtenues par rapport au seuil de certification utilisé pour le score générique a été comparée à celle précédemment publiée (III).RésultatsLe score moyen au sein du groupe « débutants » (n = 29) était significativement plus faible que celui au sein du « intermédiaires » (n = 14) (1,87 ± 0,75 et 3,31 ± 0,83 respectivement, p = 1,855) (I). Une proportion plus importante de compétences non validée a permis d’identifier l’item « documentation de l’examen » comme axe de progression prioritaire (II). La pertinence du score seuil pour discriminer les étudiants en fonction du niveau d’expertise est confortée mais un minime chevauchement entre les groupes de niveau est observé (III).ConclusionLa faisabilité et la pertinence de l’utilisation d’un score OSAUS dédié à la biométrie sont confirmées ainsi que la possibilité de comparaisons avec le score OSAUS générique

Protocol optimization of sacroiliac joint MR Imaging at 3 Tesla: Impact of coil design and motion resistant sequences on image quality

International audiencePurpose: To evaluate the impact of coil design and motion-resistant sequences on the quality of sacroiliac magnetic resonance imaging (MRI) examination in patients with spondyloarthropathy.Patients and methods: One hundred and twenty-one patients with suspected sacroiliitis and referred for MRI of the sacroiliac joints were retrospectively evaluated with MRI at 3-Tesla. There were 78 women and 43 men with a mean age of 36.7±11.5 (SD) years (range: 15.8-78.4 years). Conventional and motion-resistant fat-saturated fast-spin echo T2-weighted sequences were performed with two different coils. Image quality was subjectively evaluated by two independent readers (R1 and R2) using a four-point scale. Confidence in the identification of bone marrow edema pattern (BMEP) was also evaluated subjectively using a three-point scale.Results: Phased array body coil yielded improved image quality compared to surface coil (14.1 to 30.4% for R1 and 14.6 to 25.7% for R2; P<0.0001). The impact of the sequence type on quality was also statistically significant (P=0.0046). BMEP was identified in 40 patients and best inter-reader agreement was obtained using the combination of phased-array body coil with motion-resistant T2-weighted sequence (kappa 0.990). The smallest number of indeterminate BMEP zones was seen on MRI set acquired with the phased-array body coil and motion-resistant T2-weighted sequence.Conclusion: Phased array body coil and motion-resistant T2-weighted sequences perform better than surface coil and conventional T2-weighted sequences for the evaluation of sacroiliac joints, increasing confidence in the identification of BMEP

Fetal biometry in ultrasound: A new approach to assess the long-term impact of simulation on learning patterns

International audienceSimulation-based education (SBE) has demonstrated its acceptability and effectiveness in improving ultrasound training. Because of the high cost of its implementation (investment in equipment and supervision), a pragmatic assessment of the transfer of skills learned in SBE to clinical practice and the identification of its optimal scheduling conditions have been requested to optimize its input. Objectives: To quantify the long-term impact of simulation-based education (SBE) on the adequate performance of ultrasound fetal biometry measurements (I). The secondary objective was to identify the temporal patterns that enhanced SBE input in learning (II). Methods: Trainees were arbitrarily assigned to a 6-month course in obstetric ultrasound with or without an SBE workshop. In the SBE group, the workshop was implemented 'before' or at an 'early' or a 'late-stage' of the course. Those who did not receive SBE were the control group. The ultrasound skills of all trainees were prospectively collected, evaluated by calculating the delta between OSAUS (Objective Structured Assessment of Ultrasound Skills) scores before and after the course (I). Concomitantly, the accuracy of trainees' measurements was assessed throughout the course by verifying their correlation with the corresponding measurements by their supervisors. The percentage of trainees able to perform five consecutive sets of correct measurements in the control group and in each SBE subgroup were compared (II). Results: The study included 61 trainees (39 SBE and 22 controls). Comparisons between groups showed no significant difference in the quantitative assessment of skill enhancement (difference in the pre-and postinternship OSAUS score: 1.09 § 0.87 in the SBE group and 0.72 § 0.98 in the control group) (I). Conversely, the predefined acceptable skill level was reached by a significantly higher proportion of trainees in the 'early' SBE subgroup (74%, compared with 30% in the control group, P<0.01)(II). Conclusions: The quantitative assessment does not support the existence of long-term benefits from SBE training, although the qualitative assessment confirmed SBE helped to raise the minimal level within a group when embedded in an 'early' stage of a practical course

MDCT features of hepatocellular carcinoma (HCC) in non-cirrhotic liver

International audiencePURPOSE:To describe the multidetector row computed tomography (MDCT) imaging features of HCC that develops in patients who are free from underlying liver cirrhosis and to determine if the MDCT presentation of this specific tumor differs from that of the more common HCC that develops in patients with liver cirrhosis using a retrospective case-control study.PATIENTS AND METHODS:The MDCT examinations of 38 patients with HCC in non-cirrhotic liver (group 1) were quantitatively and qualitatively analyzed and compared to those obtained in 38 patients with HCC in cirrhotic liver (group 2) matched for age and gender. Quantitative and qualitative characteristics of HCC of both groups were compared using univariate analysis.RESULTS:HCCs were significantly larger in group 1 (81.5mm±55.5) than in group 2 (44.5mm±39.1 SD; P=0.0015). In group 1, HCCs were more frequently single tumors (87%) than in group 2 (37%) (P<0.0001), encapsulated (92% vs. 47% respectively; P<0.0001), had more frequently fatty component (24% vs. 8%, respectively; P=0.0279) and internal hemorrhage (29% vs. 3%, respectively; P=0.0033). No significant differences were found between the two groups for location, hyperenhancement of HCC during the arterial phase, washout during the portal phase, endoluminal portal involvement by HCC, endoportal cruoric thrombus, invasion of adjacent organs and underlying liver steatosis.CONCLUSION:HCC in non-cirrhotic liver are larger than those observed in cirrhotic liver and more frequently present as a single encapsulated tumor. They have the same patterns of enhancement than HCC that develops in cirrhotic liver

Metal artifact reduction for intracranial projectiles on post mortem computed tomography

International audienceTo compare the image quality of cranial post-mortem computed tomography (CT) obtained with and without projection-based single-energy metal artifact reduction (SEMAR) in cadavers with intracranial metallic ballistic projectiles. Materials and methods: From January 2017 to January 2018, cadavers with ballistic projectile head wounds with metal fragments and without massive head destruction were investigated using post-mortem CT. All subjects underwent CT using a conventional iterative reconstruction (IR) and SEMAR. To evaluate the impact of metallic artifacts, the total intracranial area (TA), non-interpretable zone (NIZ), disturbed interpretation zone (DZ), and artifact total surface (ATS) were delineated. Two independent readers identified extra-axial hemorrhage (EAH) and subarachnoid hemorrhage (SAH). Autopsy reports were used as the standard of reference. Results: Eleven corpses (10 males, 1 female; mean age, 62.8 ± 17.9 [SD] years) were evaluated. SEMAR showed a significant decrease in the ATS ratio with respect to conventional IR (72.1 ± 26.1 [SD] % [range: 26.8-99.1] vs. 86.4 ± 17.8 [SD] % [range: 37.2-100]; P < 0.001) and NIZ/TA ratios (11.6 ± 8.26% [range: 0.95-33.4] versus 42.5 ± 30.5% [range: 3.86-100]; P < 0.001). The interobserver reproducibility in diagnosing EAH and SAH was excellent with conventional IR (0.82) and good with SEMAR (0.75). SEMAR reduced uncertain diagnoses of EAH in 7 subjects for Reader 1 and in 6 for Reader 2, but did not influence the diagnosis of SAH for either reader. Conclusion: SEMAR reduces the influence of metallic artifacts and increases the confidence with which the diagnosis of EAH can be made on post-mortem CT

The Face-Processing Network Is Resilient to Focal Resection of Human Visual Cortex

International audienceHuman face perception requires a network of brain regions distributed throughout the occipital and temporal lobes with a right hemisphere advantage. Present theories consider this network as either a processing hierarchy beginning with the inferior occipital gyrus (occipital face area; IOG-faces/OFA) or a multiple-route network with nonhierarchical components. The former predicts that removing IOG-faces/OFA will detrimentally affect downstream stages, whereas the latter does not. We tested this prediction in a human patient (Patient S.P.) requiring removal of the right inferior occipital cortex, including IOG-faces/OFA. We acquired multiple fMRI measurements in Patient S.P. before and after a preplanned surgery and multiple measurements in typical controls, enabling both within-subject/across-session comparisons (Patient S.P. before resection vs Patient S.P. after resection) and between-subject/across-session comparisons (Patient S.P. vs controls). We found that the spatial topology and selectivity of downstream ipsilateral face-selective regions were stable 1 and 8 month(s) after surgery. Additionally, the reliability of distributed patterns of face selectivity in Patient S.P. before versus after resection was not different from across-session reliability in controls. Nevertheless, postoperatively, representations of visual space were typical in dorsal face-selective regions but atypical in ventral face-selective regions and V1 of the resected hemisphere. Diffusion weighted imaging in Patient S.P. and controls identifies white matter tracts connecting retinotopic areas to downstream face-selective regions, which may contribute to the stable and plastic features of the face network in Patient S.P. after surgery. Together, our results support a multiple-route network of face processing with nonhierarchical components and shed light on stable and plastic features of high-level visual cortex following focal brain damage.SIGNIFICANCE STATEMENT Brain networks consist of interconnected functional regions commonly organized in processing hierarchies. Prevailing theories predict that damage to the input of the hierarchy will detrimentally affect later stages. We tested this prediction with multiple brain measurements in a rare human patient requiring surgical removal of the putative input to a network processing faces. Surprisingly, the spatial topology and selectivity of downstream face-selective regions are stable after surgery. Nevertheless, representations of visual space were typical in dorsal face-selective regions but atypical in ventral face-selective regions and V1. White matter connections from outside the face network may support these stable and plastic features. As processing hierarchies are ubiquitous in biological and nonbiological systems, our results have pervasive implications for understanding the construction of resilient networks

Effects of reactive oxygen species on metabolism monitored by longitudinal 1 H single voxel MRS follow-up in patients with mitochondrial disease or cerebral tumors

International audienceFree radicals, or Reactive Oxygen Species (ROS), have an effect on energy and glycolytic metabolism, mitochondrial function, lipid metabolism, necrosis and apoptosis, cell proliferation, and infiltration. These changes could be monitored longitudinally (every 4 months over 6 years) in humans with glial brain tumors (low and high grade) after therapy, using conventional magnetic resonance imaging (MRI) and spectroscopy (MRS) and MR perfusion. Some examples of early clinical data from longitudinal follow-up monitoring in humans of energy and glycolytic metabolism, lipid metabolism, necrosis, proliferation, and infiltration measured by conventional MRI, MRS and perfusion, and positron emission tomography (PET) are shown in glial brain tumors after therapy. Despite the difficulty, the variability and unknown factors, these repeated measurements give us a better insight into the nature of the different processes, tumor progression and therapeutic response