Olfactory Dysfunction and Limbic Hypoactivation in Temporal Lobe Epilepsy.

The epileptogenic network in temporal lobe epilepsy (TLE) contains structures of the primary and secondary olfactory cortex such as the piriform and entorhinal cortex, the amygdala, and the hippocampus. Olfactory auras and olfactory dysfunction are relevant symptoms of TLE. This study aims to characterize olfactory function in TLE using olfactory testing and olfactory functional magnetic resonance imaging (fMRI). We prospectively enrolled 20 individuals with unilateral TLE (age 45 ± 20 years [mean ± SD], 65% female, 90% right-handed) and 20 healthy individuals (age 33 ± 15 years [mean ± SD], 35% female, 90% right-handed). In the TLE group, the presumed seizure onset zone was left-sided in 75%; in 45% of the individuals with TLE limbic encephalitis was the presumed etiology; and 15% of the individuals with TLE reported olfactory auras. Olfactory function was assessed with a Screening Sniffin' Sticks Test (Burkhart, Wedel, Germany) during a pre-assessment. During a pre-testing, all individuals were asked to rate the intensity, valence, familiarity, and associated memory of five different odors (eugenol, vanillin, phenethyl alcohol, decanoic acid, valeric acid) and a control solution. During the fMRI experiment, all individuals repeatedly smelled eugenol (positively valenced odor), valeric acid (negatively valenced odor), and the control solution and were asked to rate odor intensity on a five-point Likert scale. We acquired functional EPI sequences and structural images (T1, T2, FLAIR). Compared to healthy individuals, individuals with TLE rated the presented odors as more neutral (two-sided Mann-Whitney U tests, FDR-p < 0.05) and less familiar (two-sided Mann-Whitney U tests, FDR-p < 0.05). fMRI data analysis revealed a reduced response contrast in secondary olfactory areas (e.g., hippocampus) connected to the limbic system when comparing eugenol and valeric acid in individuals with TLE when compared with healthy individuals. However, no lateralization effect was obtained when calculating a lateralization index by the number of activated voxels in the olfactory system (two-sided Mann-Whitney U test; U = 176.0; p = 0.525). TLE is characterized by olfactory dysfunction and associated with hypoactivation of secondary olfactory structures connected to the limbic system. These findings contribute to our understanding of the pathophysiology of TLE. This study was preregistered on OSF Registries (www.osf.io).

Temporal development of subdural collections in infants with confessed abusive head trauma: a forensic neuroimaging study.

OBJECTIVES: Estimating the age of injury in pediatric abusive head trauma (AHT) is a challenging task but potentially valuable for the identification of perpetrators. The aims of the study are (1) to describe the temporal development of different imaging features of subdural collections (SDCs), and (2) to provide novel age-diagnostic reference data for forensic-radiological expert reports. METHODS: Using a multi-center approach and a 10-year study period, serial neuroimaging studies of 13 comprehensively investigated AHT cases (8 CT and 26 MRI scans) were analyzed regarding several subdural imaging parameters (SDC appearances, entities, components, and associated findings). Due to confessions by perpetrators, the time points of the trauma were presumed unique and known in all cases facilitating correlation of imaging findings with time. RESULTS: Hyperdense SDCs in CT were found up to 9 d post-injury (p.i.), CSF-like SDCs in CT or MRI as early as from the 3rd hour p.i., and subdural membrane formation as late as from day 283. The heterogeneous variant of the subdural hematohygroma was observed to be the dominant SDC entity between 3 h and 22 d p.i. The tadpole sign was detected in MRI between 3 h and 46 d p.i. CONCLUSION: Certain subdural imaging findings may be helpful for estimating the age of injury in AHT. Subdural membrane formation is demonstrated to be a late finding and the tadpole sign is an early phenomenon p.i. The data corroborated that the sediment but not the supernatant has the potential for being valuable for age-diagnostic aspects. KEY POINTS: Question Reliable evidence-based data on the development of SDCs is sparse but required for expert opinions on pediatric AHT. Findings Reference data on the evolution of the imaging appearance of SDCs and associated phenomena in confirmed cases of AHT are provided. Clinical relevance As there is a great need for estimating the age of injury in criminal and civil proceedings, many clinical radiologists are confronted with the diagnostic and forensic aspects of AHT that are addressed in the present study.

Addressing the Generalizability of AI in Radiology Using a Novel Data Augmentation Framework with Synthetic Patient Image Data: Proof-of-Concept and External Validation Classification Tasks in Multiple Sclerosis.

"Just Accepted" papers have undergone full peer review and have been accepted for publication in Radiology: Artificial Intelligence. This article will undergo copyediting, layout, and proof review before it is published in its final version. Please note that during production of the final copyedited article, errors may be discovered which could affect the content. Artificial intelligence (AI) models often face performance drops after deployment to external datasets. This study evaluated the potential of a novel data augmentation framework based on generative adversarial networks (GAN) that creates synthetic patient image data during model training to improve model generalizability. Model development and external testing were performed for a given classification task, namely the detection of new fluid-attenuated inversion recovery (FLAIR) lesions on MRI during longitudinal follow-up of patients with multiple sclerosis (MS). An internal dataset of 669 patients with MS (n = 3083 examinations) was used to develop an attention-based network, trained both with and without the inclusion of the GAN-based synthetic data augmentation framework. External testing was performed on 134 patients with MS from a different institution, with MR images acquired using different scanners and protocols than images used during training. Models trained using synthetic data augmentation showed a significant performance improvement when applied on external data (AUC 83.6% without synthetic data versus AUC 93.3% with synthetic data augmentation, P = .03), achieving comparable results to the internal test set (AUC 95.5%, P = .53), whereas models without synthetic data augmentation demonstrated a performance drop upon external testing (AUC 93.8% on internal dataset versus AUC 83.6% on external data, P = .03). Data augmentation with synthetic patient data substantially improved performance of AI models on unseen MRI data and may be extended to other clinical conditions or tasks to mitigate domain shift, limit class imbalance, and enhance the robustness of AI applications in medical imaging. ©RSNA, 2024.

Quantitative assessment of residual tumor is a strong and independent predictor of survival in methylated glioblastoma following radiochemotherapy with CCNU/TMZ.

BACKGROUND: Maximum tumor resection improves overall survival (OS) in patients with glioblastoma. The extent of resection (EOR) is historically dichotomized. The RANO resect group recently proposed criteria for volumetry-based EOR assessment in patients that were treated according to Stupp´s protocol. The purpose of this study was (1) to investigate the prognostic value of EOR in patients receiving combined chemotherapy with lomustine (CCNU)/temozolomide (TMZ), and (2) to analyse the prognostic performance of binary EOR assessment compared to volumetric assessment. METHODS: 78 patients with newly diagnosed MGMT-methylated GBM undergoing tumor resection followed by radiochemotherapy with CCNU/TMZ were included in this study. Residual contrast-enhancing (CE) tumor volume after the first resection was measured and its influence on OS and PFS was analysed using uni- and multivariable Cox regression analysis as well as two-sided log rank test. Patients were divided into RTV ≤1 cm³, >1 cm³ - ≤5 cm³ and >5 cm³ following the proposed criteria of the RANO resect group. RESULTS: Prolonged OS was associated with age <60 years, low RTV, and gross total resection (GTR). Residual tumor volume (RTV) had a superior prognostic value compared to binary EOR assessment. Patients with total or near total resection of CE tumor (≤1 cm³ RTV) showed prolonged OS (median 54.4 months, 95% CI 46.94-not reached), with a 5-year survival rate of 49%. CONCLUSION: Low RTV is associated with increased survival in glioblastoma patients undergoing radiochemotherapy with CCNU/TMZ. This study demonstrates the applicability of the recently proposed RANO resect criteria in this subgroup of patients.

Deep learning-based defacing tool for CT angiography: CTA-DEFACE.

The growing use of artificial neural network (ANN) tools for computed tomography angiography (CTA) data analysis underscores the necessity for elevated data protection measures. We aimed to establish an automated defacing pipeline for CTA data. In this retrospective study, CTA data from multi-institutional cohorts were utilized to annotate facemasks (n = 100) and train an ANN model, subsequently tested on an external institution's dataset (n = 50) and compared to a publicly available defacing algorithm. Face detection (MTCNN) and verification (FaceNet) networks were applied to measure the similarity between the original and defaced CTA images. Dice similarity coefficient (DSC), face detection probability, and face similarity measures were calculated to evaluate model performance. The CTA-DEFACE model effectively segmented soft face tissue in CTA data achieving a DSC of 0.94 ± 0.02 (mean ± standard deviation) on the test set. Our model was benchmarked against a publicly available defacing algorithm. After applying face detection and verification networks, our model showed substantially reduced face detection probability (p < 0.001) and similarity to the original CTA image (p < 0.001). The CTA-DEFACE model enabled robust and precise defacing of CTA data. The trained network is publicly accessible at www.github.com/neuroAI-HD/CTA-DEFACE . RELEVANCE STATEMENT: The ANN model CTA-DEFACE, developed for automatic defacing of CT angiography images, achieves significantly lower face detection probabilities and greater dissimilarity from the original images compared to a publicly available model. The algorithm has been externally validated and is publicly accessible. KEY POINTS: The developed ANN model (CTA-DEFACE) automatically generates facemasks for CT angiography images. CTA-DEFACE offers superior deidentification capabilities compared to a publicly available model. By means of graphics processing unit optimization, our model ensures rapid processing of medical images. Our model underwent external validation, underscoring its reliability for real-world application.

Proof of concept: Portable ultra-low-field magnetic resonance imaging for the diagnosis of epileptogenic brain pathologies.

OBJECTIVE: High-field magnetic resonance imaging (MRI) is a standard in the diagnosis of epilepsy. However, high costs and technical barriers have limited adoption in low- and middle-income countries. Even in high-income nations, many individuals with epilepsy face delays in undergoing MRI. Recent advancements in ultra-low-field (ULF) MRI technology, particularly the development of portable scanners, offer a promising solution to the limited accessibility of MRI. In this study, we present and evaluate the imaging capability of ULF MRI in detecting structural abnormalities typically associated with epilepsy and compare it to high-field MRI at 3 T. METHODS: Data collection was conducted within 3 consecutive weeks at the University Hospital Bonn. Inclusion criteria were a minimum age of 18 years, diagnosed epilepsy, and clinical high-field MRI with abnormalities. We used a .064 T Swoop portable MR Imaging System. Both high-field MRI and ULF MRI scans were evaluated independently by two experienced neuroradiologists as part of their clinical routine, comparing pathology detection and diagnosis completeness. RESULTS: Twenty-three individuals with epilepsy were recruited. One subject presented with a dual pathology. Across the entire cohort, in 17 of 24 (71%) pathologies, an anomaly colocalizing with the actual lesion was observed on ULF MRI. For 11 of 24 (46%) pathologies, the full diagnosis could be made based on ULF MRI. Tumors and posttraumatic lesions could be diagnosed best on ULF MRI, whereas cortical dysplasia and other focal pathologies were the least well diagnosed. SIGNIFICANCE: This single-center series of individuals with epilepsy demonstrates the feasibility and utility of ULF MRI for the field of epileptology. Its integration into epilepsy care offers transformative potential, particularly in resource-limited settings. Further research is needed to position ULF MRI within imaging modalities in the diagnosis of epilepsy.

A Quantitative Comparison Between Human and Artificial Intelligence in the Detection of Focal Cortical Dysplasia.

OBJECTIVES: Artificial intelligence (AI) is thought to improve lesion detection. However, a lack of knowledge about human performance prevents a comparative evaluation of AI and an accurate assessment of its impact on clinical decision-making. The objective of this work is to quantitatively evaluate the ability of humans to detect focal cortical dysplasia (FCD), compare it to state-of-the-art AI, and determine how it may aid diagnostics. MATERIALS AND METHODS: We prospectively recorded the performance of readers in detecting FCDs using single points and 3-dimensional bounding boxes. We acquired predictions of 3 AI models for the same dataset and compared these to readers. Finally, we analyzed pairwise combinations of readers and models. RESULTS: Twenty-eight readers, including 20 nonexpert and 5 expert physicians, reviewed 180 cases: 146 subjects with FCD (median age: 25, interquartile range: 18) and 34 healthy control subjects (median age: 43, interquartile range: 19). Nonexpert readers detected 47% (95% confidence interval [CI]: 46, 49) of FCDs, whereas experts detected 68% (95% CI: 65, 71). The 3 AI models detected 32%, 51%, and 72% of FCDs, respectively. The latter, however, also predicted more than 13 false-positive clusters per subject on average. Human performance was improved in the presence of a transmantle sign (P < 0.001) and cortical thickening (P < 0.001). In contrast, AI models were sensitive to abnormal gyration (P < 0.01) or gray-white matter blurring (P < 0.01). Compared with single experts, expert-expert pairs detected 13% (95% CI: 9, 18) more FCDs (P < 0.001). All AI models increased expert detection rates by up to 19% (95% CI: 15, 24) (P < 0.001). Nonexpert+AI pairs could still outperform single experts by up to 13% (95% CI: 10, 17). CONCLUSIONS: This study pioneers the comparative evaluation of humans and AI for FCD lesion detection. It shows that AI and human predictions differ, especially for certain MRI features of FCD, and, thus, how AI may complement the diagnostic workup.

Transient MRI changes and neurological deterioration in glioblastoma upon SARS-CoV-2 infection.

PURPOSE: Little is known about the effect of SARS-CoV-2 infection on glioblastoma (GBM) growth, metabolism, and prognosis. Immunological changes within GBM tissue are potentially symptomatic, underlining the urgent need for a better understanding of this phenomenon. To date, the complex underlying biology has not been fully elucidated. A decisive role of the tumor microenvironment (TME) and the components of the immune system acting within it is assumed. METHODS: Immunohistochemical staining of SARS-CoV-2 spike protein and immune cell infiltration of TME was performed on the tumor tissue of one patient. This patient developed hemiparesis 14 days after symptomatic SARS-CoV-2 infection, leading to tumor diagnosis. Subsequently and after biopsy, there was an unexpectedly good response to chemotherapy only. In looking for further evidence of the potential of SARS-CoV-2 to influence the course of GBM, two additional adult patients that had transient MRI changes and neurological deterioration following SARS-CoV-2 infection were evaluated. RESULTS: In the patient for whom neurological deterioration in the course of SARS-CoV-2 led to GBM diagnosis, immunohistochemistry revealed virus-specific protein accumulation in the tumor cells, microglial activation, and the formation of T-cell nodules. In the other two patients, the findings were compatible with symptomatic pseudoprogression that occurred in a temporal relationship with SARS-CoV-2 infection. CONCLUSION: The results indicate a possible association between clinically relevant changes in GBM biology and SARS-CoV-2 infection, with histological confirmation of SARS-CoV-2-associated changes within the tumor tissue. The exact pathomechanism and underlying inflammatory pathways require further investigation.

Rasmussen's encephalitis: structural, functional, and clinical correlates of contralesional epileptiform activity.

Progressive inflammation of one hemisphere characterises Rasmussen's encephalitis (RE), but contralesional epileptiform activity has been repeatedly reported. We aimed to quantify contralesional epileptiform activity in RE and uncover its functional and structural underpinnings. We retrospectively ascertained people with RE treated between 2000 and 2018 at a tertiary centre (Centre 1) and reviewed all available EEG datasets. The temporal occurrence of preoperative contralesional epileptiform activity (interictal/ictal) was evaluated using mixed-effects logistic regression. Cases with/without contralesional epileptiform activity were compared for cognition, inflammation (ipsilesional brain biopsies), and MRI (cortical and fixel-based morphometry). EEG findings were validated in a second cohort treated at another tertiary centre (Centre 2) between 1995 and 2020. We included 127 people with RE and 687 EEG samples. Preoperatively, contralesional epileptiform activity was seen in 30/68 (44%, Centre 1) and 8/59 (14%, Centre 2). In both cohorts, this activity was associated with younger onset age (OR = 0.9; 95% CI 0.83-0.97; P = 0.006). At centre 1, contralesional epileptiform activity was associated with contralesional MRI alterations, lower intelligence (OR = 5.19; 95% CI 1.28-21.08; P = 0.021), and impaired verbal memory (OR = 10.29; 95% CI 1.97-53.85; P = 0.006). After hemispherotomy, 11/17 (65%, Centre 1) and 28/37 (76%, Centre 2) were seizure-free. Contralesional epileptiform activity was persistent postoperatively in 6/12 (50%, Centre 1) and 2/34 (6%, Centre 2). Preoperative contralesional epileptiform activity reduced the chance of postoperative seizure freedom in both cohorts (OR = 0.69; 95% CI 0.50-0.95; P = 0.029). Our findings question the concept of strict unilaterality of RE and provide the evidence of contralesional epileptiform activity as a possible EEG predictor for persisting postoperative seizures.

Interictal blood-brain barrier dysfunction in piriform cortex of people with epilepsy.

OBJECTIVE: The piriform cortex is considered to be highly epileptogenic. Its resection during epilepsy surgery is a predictor for postoperative seizure freedom in temporal lobe epilepsy. Epilepsy is associated with a dysfunction of the blood-brain barrier. We investigated blood-brain barrier dysfunction in the piriform cortex of people with temporal lobe epilepsy using quantitative T1-relaxometry. METHODS: Gadolinium-based contrast agent was administered ictally and interictally in 37 individuals before undergoing quantitative T1-relaxometry. Postictal and interictal images were co-registered, and subtraction maps were created as biomarkers for peri-ictal (∆qT1interictal-postictal) and interictal (∆qT1noncontrast-interictal) blood-brain barrier dysfunction. Values were extracted for the piriform cortex, hippocampus, amygdala, and the whole cortex. RESULTS: In temporal lobe epilepsy (n = 14), ∆qT1noncontrast-interictal was significantly higher in the piriform cortex than in the whole cortex (p = 0.02). In extratemporal lobe epilepsy (n = 23), ∆qT1noncontrast-interictal was higher in the hippocampus than in the whole cortex (p = 0.05). Across all individuals (n = 37), duration of epilepsy was correlated with ∆qT1noncontrast-interictal (ß = 0.001, p < 0.001) in all regions, while the association was strongest in the piriform cortex. Impaired verbal memory was associated with ∆qT1noncontrast-interictal only in the piriform cortex (p = 0.04). ∆qT1interictal-postictal did not show differences in any region. INTERPRETATION: Interictal blood-brain barrier dysfunction occurs in the piriform cortex in temporal lobe epilepsy. This dysfunction is linked to longer disease duration and worse cognitive deficits, emphasizing the central role of the piriform cortex in the epileptogenic network of temporal lobe epilepsy.

Higher Validity, Lower Radiation: A New Ictal Single-Photon Emission Computed Tomography Framework.

OBJECTIVE: To assess whether arterial spin labeling perfusion images of healthy controls can enhance ictal single-photon emission computed tomography analysis and whether the acquisition of the interictal image can be omitted. METHODS: We developed 2 pipelines: The first uses ictal and interictal images and compares these to single-photon emission computed tomography and arterial spin labeling of healthy controls. The second pipeline uses only the ictal image and the analogous healthy controls. Both pipelines were compared to the gold standard analysis and evaluated on data of individuals with epilepsy who underwent ictal single-photon emission computed tomography imaging during presurgical evaluation between 2010 and 2022. Fifty healthy controls prospectively underwent arterial spin labeling imaging. The correspondence between the detected hyperperfusion and the postoperative resection cavity or the presumably affected lobe was assessed using Dice score and mean Euclidean distance. Additionally, the outcomes of the pipelines were automatically assigned to 1 of 5 concordance categories. RESULTS: Inclusion criteria were met by 43 individuals who underwent epilepsy surgery and by 73 non-surgical individuals with epilepsy. Compared to the gold standard analysis, both pipelines resulted in significantly higher Dice scores and lower mean distances (p < 0.05). The combination of both provided localizing results in 85/116 cases, compared to 54/116 generated by the current gold standard analysis and the ictal image alone produced localizing results in 60/116 (52%) cases. INTERPRETATION: We propose a new ictal single-photon emission computed tomography protocol; it finds relevantly more ictal hyperperfusion, and halves the radiation dose in about half of the individuals. ANN NEUROL 2024.

Brain and Ventricle Volume Alterations in Idiopathic Normal Pressure Hydrocephalus Determined by Artificial Intelligence-Based MRI Volumetry.

The aim of this study was to employ artificial intelligence (AI)-based magnetic resonance imaging (MRI) brain volumetry to potentially distinguish between idiopathic normal pressure hydrocephalus (iNPH), Alzheimer's disease (AD), and age- and sex-matched healthy controls (CG) by evaluating cortical, subcortical, and ventricular volumes. Additionally, correlations between the measured brain and ventricle volumes and two established semi-quantitative radiologic markers for iNPH were examined. An IRB-approved retrospective analysis was conducted on 123 age- and sex-matched subjects (41 iNPH, 41 AD, and 41 controls), with all of the iNPH patients undergoing routine clinical brain MRI prior to ventriculoperitoneal shunt implantation. Automated AI-based determination of different cortical and subcortical brain and ventricular volumes in mL, as well as calculation of population-based normalized percentiles according to an embedded database, was performed; the CE-certified software mdbrain v4.4.1 or above was used with a standardized T1-weighted 3D magnetization-prepared rapid gradient echo (MPRAGE) sequence. Measured brain volumes and percentiles were analyzed for between-group differences and correlated with semi-quantitative measurements of the Evans' index and corpus callosal angle: iNPH patients exhibited ventricular enlargement and changes in gray and white matter compared to AD patients and controls, with the most significant differences observed in total ventricular volume (+67%) and the lateral (+68%), third (+38%), and fourth (+31%) ventricles compared to controls. Global ventriculomegaly and marked white matter reduction with concomitant preservation of gray matter compared to AD and CG were characteristic of iNPH, whereas global and frontoparietally accentuated gray matter reductions were characteristic of AD. Evans' index and corpus callosal angle differed significantly between the three groups and moderately correlated with the lateral ventricular volumes in iNPH patients [Evans' index (r > 0.83, p ≤ 0.001), corpus callosal angle (r < -0.74, p ≤ 0.001)]. AI-based MRI volumetry in iNPH patients revealed global ventricular enlargement and focal brain atrophy, which, in contrast to healthy controls and AD patients, primarily involved the supratentorial white matter and was marked temporomesially and in the midbrain, while largely preserving gray matter. Integrating AI volumetry in conjunction with traditional radiologic measures could enhance iNPH identification and differentiation, potentially improving patient management and therapy response assessment.

Artificial T1-Weighted Postcontrast Brain MRI: A Deep Learning Method for Contrast Signal Extraction.

OBJECTIVES: Reducing gadolinium-based contrast agents to lower costs, the environmental impact of gadolinium-containing wastewater, and patient exposure is still an unresolved issue. Published methods have never been compared. The purpose of this study was to compare the performance of 2 reimplemented state-of-the-art deep learning methods (settings A and B) and a proposed method for contrast signal extraction (setting C) to synthesize artificial T1-weighted full-dose images from corresponding noncontrast and low-dose images. MATERIALS AND METHODS: In this prospective study, 213 participants received magnetic resonance imaging of the brain between August and October 2021 including low-dose (0.02 mmol/kg) and full-dose images (0.1 mmol/kg). Fifty participants were randomly set aside as test set before training (mean age ± SD, 52.6 ± 15.3 years; 30 men). Artificial and true full-dose images were compared using a reader-based study. Two readers noted all false-positive lesions and scored the overall interchangeability in regard to the clinical conclusion. Using a 5-point Likert scale (0 being the worst), they scored the contrast enhancement of each lesion and its conformity to the respective reference in the true image. RESULTS: The average counts of false-positives per participant were 0.33 ± 0.93, 0.07 ± 0.33, and 0.05 ± 0.22 for settings A-C, respectively. Setting C showed a significantly higher proportion of scans scored as fully or mostly interchangeable (70/100) than settings A (40/100, P < 0.001) and B (57/100, P < 0.001), and generated the smallest mean enhancement reduction of scored lesions (-0.50 ± 0.55) compared with the true images (setting A: -1.10 ± 0.98; setting B: -0.91 ± 0.67, both P < 0.001). The average scores of conformity of the lesion were 1.75 ± 1.07, 2.19 ± 1.04, and 2.48 ± 0.91 for settings A-C, respectively, with significant differences among all settings (all P < 0.001). CONCLUSIONS: The proposed method for contrast signal extraction showed significant improvements in synthesizing postcontrast images. A relevant proportion of images showing inadequate interchangeability with the reference remains at this dosage.

Stenting with dual-layer CGuard stent in acute sub-occlusive carotid artery stenosis and in tandem occlusions: a monocentric study.

PURPOSE: Double-layer design carotid stents have been cast in a negative light since several investigations reported high rates of in-stent occlusions, at least in the acute setting of tandem occlusions. CGuard is a new generation double-layered stent that was designed to prevent periinterventional embolic events. The aim of this study was to analyze the safety and efficacy of the CGuard in emergent CAS and for the acute treatment of tandem occlusions in comparison with the single-layer Carotid Wallstent (CWS) system. METHODS: All patients who underwent CAS with CGuard or CWS after intracranial mechanical thrombectomy (MT) between 11/2018 and 12/2022 were identified from our local thrombectomy registry. Clinical, interventional and neuroimaging data were analyzed. Patency of the stent was assessed within 72 h. Intracranial hemorrhage and modified Rankin score (mRS) at discharge were the main endpoints. RESULTS: In total, 86 stent procedures in 86 patients were included (CWS: 44, CGuard: 42). CGuard had a lower, but not statistically significant rate (p = 0.431) of in-stent occlusions (n = 2, 4.8%) when compared to the CWS (n = 4, 9.1%). Significant in-stent stenosis was found in one case in each group. There was no statistically significant difference in functional outcome at discharge between the two groups with a median mRS for CGuard of 2 (IQR:1-5) vs. CWS 3 (IQR:2-4). CONCLUSION: In our series, the rate of in-stent occlusions after emergent CAS was lower with the dual-layer CGuard when compared to the monolayer CWS. Further data are needed to evaluate the potential benefit of the design in more detail.

Differential modulation of resting-state functional connectivity between amygdala and precuneus after acute physical exertion of varying intensity: indications for a role in affective regulation.

Introduction: Physical activity influences psychological well-being. This study aimed to determine the impact of exercise intensity on psychological well-being and alterations in emotion-related brain functional connectivity (FC). Methods: Twenty young, healthy, trained athletes performed a low- and high-intensity interval exercise (LIIE and HIIE) as well as a control condition in a within-subject crossover design. Before and after each condition, Positive And Negative Affect Scale (PANAS) was assessed as well as resting-state functional MRI (rs-fMRI). Voxel-wise FC was examined for bilateral amygdala seed region to whole-brain and emotion-related anatomical regions (e.g., insula, temporal pole, precuneus). Data analyses were performed using linear mixed-effect models with fixed factors condition and time. Results: The PANAS Positive Affect scale showed a significant increase after LIIE and HIIE and a significant reduction in Negative Affect after the control condition. In rs-fMRI, no significant condition-by-time interactions were observed between the amygdala and whole brain. Amygdala-precuneus FC analysis showed an interaction effect, suggesting reduced post-exercise anticorrelation after the control condition, but stable, or even slightly enhanced anticorrelation for the exercise conditions, especially HIIE. Discussion: In conclusion, both LIIE and HIIE had positive effects on mood and concomitant effects on amygdala-precuneus FC, particularly after HIIE. Although no significant correlations were found between amygdala-precuneus FC and PANAS, results should be discussed in the context of affective disorders in whom abnormal amygdala-precuneus FC has been observed.

Contrast media for hysterosalpingography: systematic search and review providing new guidelines by the Contrast Media Safety Committee of the European Society of Urogenital Radiology.

OBJECTIVES: Hysterosalpingography (HSG) is widely used for evaluating the fallopian tubes; however, controversies regarding the use of water- or oil-based iodine-based contrast media (CM) remain. The aim of this work was (1) to discuss reported pregnancy rates related to the CM type used, (2) to validate the used CM in published literature, (3) to discuss possible complications and side effects of CM in HSG, and (4) to develop guidelines on the use of oil-based CM in HSG. METHODS: A systematic literature search was conducted for original RCT studies or review/meta-analyses on using water-based and oil-based CM in HSG with fertility outcomes and complications. Nine randomized controlled trials (RCTs) and 10 reviews/meta-analyses were analyzed. Grading of the literature was performed based on the Oxford Centre for Evidence-Based Medicine (OCEBM) 2011 classification. RESULTS: An approximately 10% higher pregnancy rate is reported for oil-based CM. Side effects are rare, but oil-based CM have potentially more side effects on the maternal thyroid function and the peritoneum. CONCLUSIONS: 1. HSG with oil-based CM gives approximately 10% higher pregnancy rates. 2. External validity is limited, as in five of nine RCTs, the CM used is no longer on the market. 3. Oil-based CM have potentially more side effects on the maternal thyroid function and on the peritoneum. 4. Guideline: Maternal thyroid function should be tested before HSG with oil-based CM and monitored for 6 months after. CLINICAL RELEVANCE STATEMENT: Oil-based CM is associated with an approximately 10% higher chance of pregnancy compared to water-based CM after HSG. Although side effects are rare, higher iodine concentration and slower clearance of oil-based CM may induce maternal thyroid function disturbance and peritoneal inflammation and granuloma formation. KEY POINTS: • It is unknown which type of contrast medium, oil-based or water-based, is the optimal for HSG. • Oil-based contrast media give a 10% higher chance of pregnancy after HSG, compared to water-based contrast media. • From the safety perspective, oil-based CM can cause thyroid dysfunction and an intra-abdominal inflammatory response in the patient.

Inverted U-shape-like functional connectivity alterations in cognitive resting-state networks depending on exercise intensity: An fMRI study.

Acute physical activity influences cognitive performance. However, the relationship between exercise intensity, neural network activity, and cognitive performance remains poorly understood. This study examined the effects of different exercise intensities on resting-state functional connectivity (rsFC) and cognitive performance. Twenty male athletes (27.3 ± 3.6 years) underwent cycling exercises of different intensities (high, low, rest/control) on different days in randomized order. Before and after, subjects performed resting-state functional magnetic resonance imaging and a behavioral Attention Network Test (ANT). Independent component analysis and Linear mixed effects models examined rsFC changes within ten resting-state networks. No significant changes were identified in ANT performance. Resting-state analyses revealed a significant interaction in the Left Frontoparietal Network, driven by a non-significant rsFC increase after low-intensity and a significant rsFC decrease after high-intensity exercise, suggestive of an inverted U-shape relationship between exercise intensity and rsFC. Similar but trend-level rsFC interactions were observed in the Dorsal Attention Network (DAN) and the Cerebellar Basal Ganglia Network. Explorative correlation analysis revealed a significant positive association between rsFC increases in the right superior parietal lobule (part of DAN) and better ANT orienting in the low-intensity condition. Results indicate exercise intensity-dependent subacute rsFC changes in cognition-related networks, but their cognitive-behavioral relevance needs further investigation.

Impact of an AI software on the diagnostic performance and reading time for the detection of cerebral aneurysms on time of flight MR-angiography.

PURPOSE: To evaluate the impact of an AI-based software trained to detect cerebral aneurysms on TOF-MRA on the diagnostic performance and reading times across readers with varying experience levels. METHODS: One hundred eighty-six MRI studies were reviewed by six readers to detect cerebral aneurysms. Initially, readings were assisted by the CNN-based software mdbrain. After 6 weeks, a second reading was conducted without software assistance. The results were compared to the consensus reading of two neuroradiological specialists and sensitivity (lesion and patient level), specificity (patient level), and false positives per case were calculated for the group of all readers, for the subgroup of physicians, and for each individual reader. Also, reading times for each reader were measured. RESULTS: The dataset contained 54 aneurysms. The readers had no experience (three medical students), 2 years experience (resident in neuroradiology), 6 years experience (radiologist), and 12 years (neuroradiologist). Significant improvements of overall specificity and the overall number of false positives per case were observed in the reading with AI support. For the physicians, we found significant improvements of sensitivity on lesion and patient level and false positives per case. Four readers experienced reduced reading times with the software, while two encountered increased times. CONCLUSION: In the reading with the AI-based software, we observed significant improvements in terms of specificity and false positives per case for the group of all readers and significant improvements of sensitivity and false positives per case for the physicians. Further studies are needed to investigate the effects of the AI-based software in a prospective setting.

Data Extraction from Free-Text Reports on Mechanical Thrombectomy in Acute Ischemic Stroke Using ChatGPT: A Retrospective Analysis.

Background Procedural details of mechanical thrombectomy in patients with ischemic stroke are important predictors of clinical outcome and are collected for prospective studies or national stroke registries. To date, these data are collected manually by human readers, a labor-intensive task that is prone to errors. Purpose To evaluate the use of the large language models (LLMs) GPT-4 and GPT-3.5 to extract data from neuroradiology reports on mechanical thrombectomy in patients with ischemic stroke. Materials and Methods This retrospective study included consecutive reports from patients with ischemic stroke who underwent mechanical thrombectomy between November 2022 and September 2023 at institution 1 and between September 2016 and December 2019 at institution 2. A set of 20 reports was used to optimize the prompt, and the ability of the LLMs to extract procedural data from the reports was compared using the McNemar test. Data manually extracted by an interventional neuroradiologist served as the reference standard. Results A total of 100 internal reports from 100 patients (mean age, 74.7 years ± 13.2 [SD]; 53 female) and 30 external reports from 30 patients (mean age, 72.7 years ± 13.5; 18 male) were included. All reports were successfully processed by GPT-4 and GPT-3.5. Of 2800 data entries, 2631 (94.0% [95% CI: 93.0, 94.8]; range per category, 61%-100%) data points were correctly extracted by GPT-4 without the need for further postprocessing. With 1788 of 2800 correct data entries, GPT-3.5 produced fewer correct data entries than did GPT-4 (63.9% [95% CI: 62.0, 65.6]; range per category, 14%-99%; P < .001). For the external reports, GPT-4 extracted 760 of 840 (90.5% [95% CI: 88.3, 92.4]) correct data entries, while GPT-3.5 extracted 539 of 840 (64.2% [95% CI: 60.8, 67.4]; P < .001). Conclusion Compared with GPT-3.5, GPT-4 more frequently extracted correct procedural data from free-text reports on mechanical thrombectomy performed in patients with ischemic stroke. © RSNA, 2024 Supplemental material is available for this article.

Human brain clearance imaging: Pathways taken by magnetic resonance imaging contrast agents after administration in cerebrospinal fluid and blood.

Over the last decade, it has become evident that cerebrospinal fluid (CSF) plays a pivotal role in brain solute clearance through perivascular pathways and interactions between the brain and meningeal lymphatic vessels. Whereas most of this fundamental knowledge was gained from rodent models, human brain clearance imaging has provided important insights into the human system and highlighted the existence of important interspecies differences. Current gold standard techniques for human brain clearance imaging involve the injection of gadolinium-based contrast agents and monitoring their distribution and clearance over a period from a few hours up to 2 days. With both intrathecal and intravenous injections being used, which each have their own specific routes of distribution and thus clearance of contrast agent, a clear understanding of the kinetics associated with both approaches, and especially the differences between them, is needed to properly interpret the results. Because it is known that intrathecally injected contrast agent reaches the blood, albeit in small concentrations, and that similarly some of the intravenously injected agent can be detected in CSF, both pathways are connected and will, in theory, reach the same compartments. However, because of clear differences in relative enhancement patterns, both injection approaches will result in varying sensitivities for assessment of different subparts of the brain clearance system. In this opinion review article, the "EU Joint Programme - Neurodegenerative Disease Research (JPND)" consortium on human brain clearance imaging provides an overview of contrast agent pharmacokinetics in vivo following intrathecal and intravenous injections and what typical concentrations and concentration-time curves should be expected. This can be the basis for optimizing and interpreting contrast-enhanced MRI for brain clearance imaging. Furthermore, this can shed light on how molecules may exchange between blood, brain, and CSF.