Deep brain stimulation (DBS) is a new neurosurgical method principally used for the treatment of ... more Deep brain stimulation (DBS) is a new neurosurgical method principally used for the treatment of Parkinson disease (PD). Many new applications of DBS are under development, including the treatment of intractable psychiatric diseases. Brain imaging is used for the selection of patients for DBS, to localize the target nucleus, to detect complications, and to evaluate the final electrode contact position. In patients with implanted DBS systems, there is a risk of electrode heating when MR imaging is performed. This contraindicates MR imaging unless specific precautions are taken. Involvement of neuroradiologists in DBS procedures is essential to optimize presurgical evaluation, targeting, and postoperative anatomic results. The precision of the neuroradiologic correlation with anatomic data and clinical outcomes in DBS promises to yield significant basic science and clinical advances in the future.
Background and Objective As deep learning faces a reproducibility crisis and studies on deep lear... more Background and Objective As deep learning faces a reproducibility crisis and studies on deep learning applied to neuroimaging are contaminated by methodological flaws, there is an urgent need to provide a safe environment for deep learning users to help them avoid common pitfalls that will bias and discredit their results. Several tools have been proposed to help deep learning users design their framework for neuroimaging data sets. Methods We present here ClinicaDL, one of these software tools. Clini-caDL interacts with BIDS, a standard format in the neuroimaging field, and its derivatives, so it can be used with a large variety of data sets. Moreover, it checks the absence of data leakage when inferring the results of new data with trained networks, and saves all necessary information to guarantee the reproducibility of results. Results The combination of ClinicaDL and its companion project Clinica allows performing an end-to-end neuroimaging analysis, from the download of raw data sets to the interpretation of trained networks, including neuroimaging Preprint submitted to Computer Methods and Programs in BiomedicineSeptember 7, 2021 preprocessing, quality check, label definition, architecture search, and network training and evaluation. Conclusions We implemented ClinicaDL to bring answers to three common issues encountered by deep learning users who are not always familiar with neuroimaging data: (1) the format and preprocessing of neuroimaging data sets, (2) the contamination of the evaluation procedure by data leakage and (3) a lack of reproducibility. We hope that its use by researchers will allow producing more reliable and thus valuable scientific studies in our field.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Didier Dormont, Olivier Colliot, APPRIMAGE Study Group • We propose a framework for the automatic... more Didier Dormont, Olivier Colliot, APPRIMAGE Study Group • We propose a framework for the automatic QC of 3D T1w brain MRI for a clinical data warehouse. • We manually labeled 5500 images to train/test different convolutional neural networks. • The automatic approach can identify images which are not proper T1w brain MRIs (e.g. truncated images). • It is able to identify acquisitions for which gadolinium was injected. • It can also accurately identify low quality images.
BMC medical informatics and decision making, Jan 19, 2017
Predicting progression from a stage of Mild Cognitive Impairment to dementia is a major pursuit i... more Predicting progression from a stage of Mild Cognitive Impairment to dementia is a major pursuit in current research. It is broadly accepted that cognition declines with a continuum between MCI and dementia. As such, cohorts of MCI patients are usually heterogeneous, containing patients at different stages of the neurodegenerative process. This hampers the prognostic task. Nevertheless, when learning prognostic models, most studies use the entire cohort of MCI patients regardless of their disease stages. In this paper, we propose a Time Windows approach to predict conversion to dementia, learning with patients stratified using time windows, thus fine-tuning the prognosis regarding the time to conversion. In the proposed Time Windows approach, we grouped patients based on the clinical information of whether they converted (converter MCI) or remained MCI (stable MCI) within a specific time window. We tested time windows of 2, 3, 4 and 5 years. We developed a prognostic model for each t...
Objectifs L'objectif de cette étude était de caractériser, par une approche cerveau-entier à l'éc... more Objectifs L'objectif de cette étude était de caractériser, par une approche cerveau-entier à l'échelle du voxel, le profil d'hypométabolisme en TEP au 18FDG des différents sous-types d'épilepsie du lobe temporal (ELT), comme définis par Stéreo-Électro-EncéphaloGraphie (SEEG) et de déterminer la valeur prédictive de l'examen TEP sur les résultats post-opératoires. Matériels et méthodes Quarante-quatre patients avec ELT pharmacorésistante ont été rétrospectivement inclus après évaluation pré-chirurgicale, permettant de définir : 7 ELT latérales, 18 ELT mésiales, 14 ELT élargies et 16 ELT bilatérales. L'analyse statistique à l'échelle du voxel était réalisée pour chaque sous-groupe de patients en comparaison de 23 sujets sains et une classification individuelle était conduite par validation croisée à partir des clusters extraits. Un index métabolique était, par ailleurs, calculé pour chaque patient à partir du Z-score le plus significatif. Une analyse de régression logistique était utilisée pour estimer les facteurs associés au devenir post-opératoire (classification d'Engel), incluant : l'âge, la durée de la maladie, la fréquence des crises et les résultats de l'IRM et de la TEP. Résultats Différents profils d'hypométabolisme étaient retrouvés, au sein et en dehors de la zone épileptogène, parmi les sous-groupes distincts d'ELT, en comparaison des sujets sains (P < 0,001 ; corrigé pour le cluster). À l'échelle individuelle, la validation croisée montrait une classification satisfaisante des 4 sous-groupes de patients avec une exactitude comprise entre 71,4 et 88,2 %. L'analyse multi-variée montrait que la TEP au 18FDG était l'unique prédicteur significatif du devenir post-opératoire (P = 0,037). Conclusions Cette étude en TEP au 18FDG valide les profils spécifiques d'hypométabolismes des différents sous-types d'ELT définis par le goldstandard de la SEEG et la relation avec le pronostic post-opératoire. Déclaration de liens d'intérêts Les auteurs déclarent ne pas avoir de liens d'intérêts.
Akinetic mustism is a dramatic deficit in spontaneous initiation of voluntary motor and speech ac... more Akinetic mustism is a dramatic deficit in spontaneous initiation of voluntary motor and speech acts, usually secondary to bilateral lesions of the anterior cingulate cortices and supplementary motor areas [1]. Given the obvious limitations of traditional neuropsychological testing in this clinical context, the use of neurophysiological tools such as bedside auditory cognitive event-related potentials (ERPs), recently proven to be relevant to evaluate comatose and vegetative patients [Clin. Neurophysiol. 110 (9) (1999) 1601; News Physiol. Sci. 17 (2002) 38], may constitute an interesting alternative. Here, we present the ERPs of a 38-year-old right-handed woman with severe akinetic mutism recorded in a passive auditory odd-ball paradigm. In spite of this severe clinical state, we could observe the presence of a ''Mismatch Negativity'', and of a larger P300 in rare trials than in frequent ones. By revealing a high level of cognitive integration of environmental auditory information, our study emphasizes the potential clinical relevance of MMN and P300 recordings in akinetic mutism to assess patient cognitive functioning.
Within primary progressive aphasia the logopenic variant remains less understood than the two oth... more Within primary progressive aphasia the logopenic variant remains less understood than the two other main variants, namely semantic and non-fluent progressive aphasia. This may be because of the relatively small number of explored patients and because of the lack of investigations with a comprehensive three-level characterization of cognitive, brain localization and biological aspects. The aim of the present study was to decipher the logopenic variant through a multimodal approach with a large cohort of 19 patients (age 66.5 AE 8.7 years, symptom duration 3.2 AE 0.6 years) using detailed cognitive and linguistic assessments, magnetic resonance imaging and perfusion single-photon emission computed tomography as well as cerebrospinal fluid biomarkers screening for Alzheimer pathology. The linguistic assessment unveiled that language dysfunction is not limited to the typical feature of word finding and verbal working memory impairments but that it extends into the language system affecting to some degree syntactic production, phonological encoding and semantic representations. Perfusion tomography revealed damage of the temporal-parietal junction with a peak of significance in the superior temporal gyrus (Brodmann area 42), and of some less significant prefrontal areas (Brodmann areas 8, 9 and 46), whereas hippocampal cortices were unaffected. Magnetic resonance imaging, which was visually assessed in a larger group of 54 patients with logopenic, non-fluent, semantic variants as well as with posterior cortical atrophy, confirmed that the logopenic variant demonstrates predominant atrophy of left temporal-parietal junction, but that this atrophy pattern has a relatively poor sensitivity and specificity for clinical diagnosis. Finally, the biomarker study revealed that two-thirds of the logopenic patients demonstrated a profile indicative of Alzheimer pathology whereas one-third had a non-Alzheimer profile. Splitting the two groups showed that logopenic aphasia due to probable Alzheimer pathology is a more aggressive variant characterized by more extensive language/cognitive disorders affecting, in addition to lexical processes and verbal working memory, also phoneme sequencing, semantic processing and ideomotor praxis. Concordantly, logopenic aphasia due to probable Alzheimer pathology demonstrated more extensive brain hypoperfusion involving larger regions throughout the inferior parietal, the posterior-superior and the middle temporal cortex. These findings allow for unfolding logopenic aphasia into two subvariants differing by disease severity, lesion nature and lesion distribution, which has important implications for diagnosis, patient management and for potential future trials with
Early identification of patients at risk of space-occupying &amp;amp;amp;amp;amp;amp;amp;amp;... more Early identification of patients at risk of space-occupying &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;malignant&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; middle cerebral artery (MCA) infarction (MMI) is needed to enable timely decision for potentially life-saving treatment such as decompressive hemicraniectomy. We tested the hypothesis that acute stroke magnetic resonance imaging (MRI) predicts MMI within 6 hours of stroke onset. In a prospective, multicenter, observational cohort study patients with acute ischemic stroke and MCA main stem occlusion were studied by MRI including diffusion-weighted imaging (DWI), perfusion imaging (PI), and MR-angiography within 6 hours of symptom onset. Multivariate regression analysis was used to identify clinical and imaging predictors of MMI. Of 140 patients included, 27 (19.3%) developed MMI. The following parameters were identified as independent predictors of MMI: larger acute DWI lesion volume (per 1 ml odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.06; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), combined MCA + internal carotid artery occlusion (5.38, 1.55-18.68; p = 0.008), and severity of neurological deficit on admission assessed by the National Institutes of Health Stroke Scale score (per 1 point 1.16, 1.00-1.35; p = 0.053). The prespecified threshold of a DWI lesion volume &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;82 ml predicted MMI with high specificity (0.98, 95% CI 0.94-1.00), negative predictive value (0.90, 0.83-0.94), and positive predictive value (0.88, 0.62-0.98), but sensitivity was low (0.52, 0.32-0.71). Stroke MRI on admission predicts malignant course in severe MCA stroke with high positive and negative predictive value and may help in guiding treatment decisions, such as decompressive surgery. In a subset of patients with small initial DWI lesion volumes, repeated diagnostic tests are required.
The physiopathologic bases underlying the signal intensity changes and reduced diffusibility obse... more The physiopathologic bases underlying the signal intensity changes and reduced diffusibility observed in prion diseases (TSEs) are still poorly understood. We evaluated the interest of MRS combined with DWI both as a diagnostic tool and a way to understand the mechanism underlying signal intensity and ADC changes in this setting. MATERIALS AND METHODS: We designed a prospective study of multimodal MR imaging in patients with suspected TSEs. Forty-five patients with a suspicion of TSE and 11 age-matched healthy volunteers were included. The MR imaging protocol included T1, FLAIR, and DWI sequences. MRS was performed on the cerebellum, pulvinar, right lenticular nucleus, and frontal cortex. MR images were assessed visually, and ADC values were calculated. RESULTS: Among the 45 suspected cases, 31 fulfilled the criteria for probable or definite TSEs (19 sCJDs, 3 iCJDs, 2 vCJDs, and 7 genetic TSEs); and 14 were classified as AltDs. High signals in the cortex and/or basal ganglia were observed in 26/31 patients with TSEs on FLAIR and 29/31 patients on DWI. In the basal ganglia, high DWI signals corresponded to a decreased ADC. Metabolic alterations, increased mIns, and decreased NAA were observed in all patients with TSEs. ADC values and metabolic changes were not correlated; this finding suggests that neuronal stress (vacuolization), neuronal loss, and astrogliosis do not alone explain the decrease of ADC. CONCLUSIONS: MRS combined with other MR imaging is of interest in the diagnosis of TSE and provides useful information for understanding physiopathologic processes underlying prion diseases. ABBREVIATIONS: ADC ϭ apparent diffusion coefficient; AltD ϭ alternative diagnosis; Avg ϭ average; C (or c) ϭ control; Cho ϭ choline; CJD ϭ Creutzfeldt-Jakob disease; Cr ϭ creatine; DWI ϭ diffusionweighted imaging; EEG ϭ electroencephalograph; FFI ϭ fatal familial insomnia; FLAIR ϭ fluid-attenuated inversion recovery; GABA ϭ gamma-aminobutyric acid; gCJD ϭ genetic CJD; Glx ϭ glutamineglutamate-GABA; GSS ϭ Gerstmann Strausser Sheinker syndrome; iCJD ϭ iatrogenic CJD; mIns ϭ myo-inositol; MM ϭ methionine homozygosity (PRNP: genotype at codon 129); MRS ϭ MR spectroscopy; MRI ϭ MR imaging; MV ϭ methionine-valine heterozygosity (PRNP: genotype at codon 129); NA ϭ data not available; NAA ϭ N-acetylaspartate; NS ϭ not significant or nonspecific slow waves; P (or p) ϭ patient; PRNP ϭ genotype at codon 129; PrP ϭ prion protein or persistent plexus gene; S ϭ sum of metabolites; sCJD ϭ sporadic CJD; TSE ϭ human transmissible spongiform encephalopathy; vCJD ϭ variant CJD; VV ϭ valine homozygosity (PRNP: genotype at codon 129)
Anne Bertrand passed away on March 2nd 2018. She was in a touring-skiers group led by a guide and... more Anne Bertrand passed away on March 2nd 2018. She was in a touring-skiers group led by a guide and swept by an avalanche in the French Alps. This paper is a tribute to Anne and an attempt, by some of her closest colleagues, to provide an overview of her major contributions. Anne Bertrand was a rising star of the neuroimaging community who traced innovative paths at the interface of basic science and clinical neuroradiology. From the very beginning of her career, she had been interested in the cross-fertilization between research and medical practice. After an MD and a specialization in neuroradiology, she prepared a PhD in preclinical imaging at the French Atomic Energy Commission (CEA) and at New York University. She was then appointed as Senior Neuroradiologist (at the Pitié-Salpêtrière and then Saint-Antoine Hospital in Paris) and Associate Professor (Sorbonne University). Simultaneously, she continued to develop her research activities in the ARAMIS Laboratory at the Brain and Spinal Cord Institute (ICM). Her main field of interest was neuroimaging of dementias. In a short time, she made important and exceptionally diverse contributions to the understanding, detection, diagnosis and tracking of these disorders (including Alzheimer's disease and fronto-temporal lobar degeneration) using advanced multimodal neuroimaging techniques. They will be a source of inspiration for all of us. Anne was not only an outstandingly bright scientist but also enlightening by her personal qualities: joy, openness, kindness and generosity.
Objective: To describe a reversible neurological condition resembling a crossed midbrain syndrome... more Objective: To describe a reversible neurological condition resembling a crossed midbrain syndrome resulting from high frequency stimulation (HFS) in the midbrain. Methods: Postoperative evaluation of quadripolar electrodes implanted in the area of the subthalamic nucleus of 25 patients with Parkinson's disease (PD) successfully treated by HFS. Results: Four of the 25 patients experienced reversible acute diplopia, with dystonic posture and tremor in the contralateral upper limb when the white matter between the red nucleus and the substantia nigra was stimulated. The motor signs resembled those caused by lesions of the red nucleus. The ipsilateral resting eye position was "in and down" (three patients) or "in" (one patient). Enophthalmos was seen. Abduction was impaired and vertical eye movements were limited, but adduction was spared. The movements of the controlateral eye were normal. The ocular signs could be best explained by sustained hyperactivity of the extrinsic oculomotor nerve. Simultaneous tonic contraction of the superior rectus, the inferior rectus, and inferior oblique may cause the enophthalmos and partial limitation of upward and downward eye movements. Antagonist tonic contraction of the ipsilateral medial rectus severely impairs abduction. Conclusion: This crossed midbrain syndrome, possibly resulting from simultaneous activation of oculomotor nerve and lesion-like inhibition of the red nucleus suggests that high frequency stimulation has opposite effects on grey and white matter.
To report a method of electrode implantation in the ventralis intermedius nucleus of the thalamus... more To report a method of electrode implantation in the ventralis intermedius nucleus of the thalamus for the treatment of tremor using a 3-D stereotactic MR imaging technique. METHODS: Five patients (three men and two women; mean age, 59 years) with medically refractory tremor had intrathalamic implantation of a stimulating electrode. Stereotactic MR imaging was performed on a 1.5-T unit equipped with an MR-compatible Leksell G stereotactic frame fixed to the patient's head. Calculation of the coordinates of the theoretical target was based on the coordinates of the anterior commissure, the posterior commissure, and the midline sagittal plane as determined via stereotactic MR imaging. During the surgical procedure, the best position for the stimulating electrode was determined by electrophysiological and clinical studies. Postoperative MR control studies were done in all cases to verify the position of the electrode. RESULTS: Stereotactic MR imaging allowed precise implantation of the stimulating electrode in all patients. Electrode stimulation produced a 90% reduction of the tremor in two patients, an 80% and 70% reduction in one patient each, and a persistent microthalamotomy-like effect in the fifth patient. Examination of the MR control studies showed that mean error in the positioning of the electrodes was 0.77 Ϯ 0.6 mm (mean Ϯ SD) in the x direction and 0.80 Ϯ 1.02 mm in the y direction. CONCLUSION: Although our series is relatively small, the precision achieved with stereotactic MR imaging proves that it can be used with confidence for precise functional neurosurgical procedures.
Background: High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment... more Background: High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for advanced forms of Parkinson disease. Postoperative improvement of motor parkinsonian disability is known to depend on patient selection and surgical targeting. Objective: To determine which clinical and electrophysiological variables evaluated during the operation predict the postoperative clinical outcome of patients with Parkinson disease treated by bilateral high-frequency stimulation of the STN. Methods: Intraoperative clinical and electrophysiological data obtained in 41 patients with Parkinson disease who underwent bilateral implantation of electrodes for STN stimulation were correlated with the improvement in parkinsonian disability assessed 6 months after the operation. Results: The extent of STN neuronal activity recorded along the trajectory of the therapeutic electrode had no effect on the postoperative clinical outcome. The intraoperative improvement in segmental akinesia, but not rigidity, was predictive of the postoperative improvement in parkinsonian motor disability and reduction in daily levodopaequivalent dosage. Parkinsonian motor disability scores assessed after surgery were lower in patients with intraoperative stimulation-induced dyskinesias than in those without stimulation-induced dyskinesias. Conclusion: The improvement of segmental akinesia and the observation of dyskinesias provoked by stimulation during the operation predict the best postoperative effects of bilateral STN stimulation on parkinsonian motor disability.
Objectives QyScore® is an imaging analysis tool certified in Europe (CE marked) and the US (FDA c... more Objectives QyScore® is an imaging analysis tool certified in Europe (CE marked) and the US (FDA cleared) for the automatic volumetry of grey and white matter (GM and WM respectively), hippocampus (HP), amygdala (AM), and white matter hyperintensity (WMH). Here we compare QyScore® performances with the consensus of expert neuroradiologists. Methods Dice similarity coefficient (DSC) and the relative volume difference (RVD) for GM, WM volumes were calculated on 50 3DT1 images. DSC and the F1 metrics were calculated for WMH on 130 3DT1 and FLAIR images. For each index, we identified thresholds of reliability based on current literature review results. We hypothesized that DSC/F1 scores obtained using QyScore® markers would be higher than the threshold. In contrast, RVD scores would be lower. Regression analysis and Bland–Altman plots were obtained to evaluate QyScore® performance in comparison to the consensus of three expert neuroradiologists. Results The lower bound of the DSC/F1 conf...
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. How serious is data leakage in deep learning studies on Alzheimer’s disease classification? Junhao Wen, Elina Thibeau-Sutre, Jorge Samper-Gonzalez, Alexandre Routier, Simona Bottani, Didier Dormont, Stanley Durrleman , Olivier Colliot, Ninon Burgos
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Alzheimer's & Dementia: Translational Research & Clinical Interventions, 2021
Introduction: We aim to understand how patients with Alzheimer's disease (AD) are treated by iden... more Introduction: We aim to understand how patients with Alzheimer's disease (AD) are treated by identifying in a longitudinal fashion the late-life changes in patients' medical history that precede and follow AD diagnosis. Methods: We use prescription history of 34,782 patients followed between 1996 and 2019 by French general practitioners. We compare patients with an AD diagnosis, patients with mild cognitive impairment (MCI), and patients free of mental disorders. We use a generalized mixed-effects model to study the longitudinal changes in the prescription of eight drug types for a period 15 years before diagnosis and 10 years after. Results: In the decades preceding diagnosis, we find that future AD patients are treated significantly more than MCI patients with most psychotropic drugs and that most studied drugs are increasingly prescribed with age. At the time of diagnosis, all psychotropic drugs except benzodiazepines show a significant increase in prescription, while other drugs are significantly less prescribed. In the 10 years after diagnosis, nearly all categories of drugs are less and less prescribed including antidementia drugs. Discussion: Pre-diagnosis differences between future AD patients and MCI patients may indicate that subtle cognitive changes are recognized and treated as psychiatric symptoms. The disclosure of AD diagnosis drastically changes patients' care, priority being given to the management of psychiatric symptoms. The decrease of all prescriptions in the late stages may reflect treatment discontinuation and simplification of therapeutic procedures. This study therefore provides new insights into the medical practices for management of AD.
Preoperative embolization of Hypervascular Spinal Metastases (HSM) is efficient to reduce periope... more Preoperative embolization of Hypervascular Spinal Metastases (HSM) is efficient to reduce perioperative bleeding. However, intra-arterial digital subtraction angiography (IA-DSA) must confirm the hypervascular nature and rule out spinal cord arterial feeders. This study aimed to evaluate the reliability and accuracy of Time Resolved Contrast Enhanced Magnetic Resonance Angiography (TR-CE-MRA) in assessing HSM prior to embolization. Methods All consecutive patients referred for preoperative embolization of an HSM were prospectively included. TR-CE-MRA sequences and selective IA-DSA were performed prior to embolization. Two readers independently reviewed imaging data to grade tumour vascularity (using a 3grade and a dichotomized "yes vs no" scale) and identify the arterial supply of the spinal cord. Interobserver and intermodality agreements were estimated using kappa statistics. Results Thirty patients included between 2016 and 2019 were assessed for 55 levels.
Deep brain stimulation (DBS) is a new neurosurgical method principally used for the treatment of ... more Deep brain stimulation (DBS) is a new neurosurgical method principally used for the treatment of Parkinson disease (PD). Many new applications of DBS are under development, including the treatment of intractable psychiatric diseases. Brain imaging is used for the selection of patients for DBS, to localize the target nucleus, to detect complications, and to evaluate the final electrode contact position. In patients with implanted DBS systems, there is a risk of electrode heating when MR imaging is performed. This contraindicates MR imaging unless specific precautions are taken. Involvement of neuroradiologists in DBS procedures is essential to optimize presurgical evaluation, targeting, and postoperative anatomic results. The precision of the neuroradiologic correlation with anatomic data and clinical outcomes in DBS promises to yield significant basic science and clinical advances in the future.
Background and Objective As deep learning faces a reproducibility crisis and studies on deep lear... more Background and Objective As deep learning faces a reproducibility crisis and studies on deep learning applied to neuroimaging are contaminated by methodological flaws, there is an urgent need to provide a safe environment for deep learning users to help them avoid common pitfalls that will bias and discredit their results. Several tools have been proposed to help deep learning users design their framework for neuroimaging data sets. Methods We present here ClinicaDL, one of these software tools. Clini-caDL interacts with BIDS, a standard format in the neuroimaging field, and its derivatives, so it can be used with a large variety of data sets. Moreover, it checks the absence of data leakage when inferring the results of new data with trained networks, and saves all necessary information to guarantee the reproducibility of results. Results The combination of ClinicaDL and its companion project Clinica allows performing an end-to-end neuroimaging analysis, from the download of raw data sets to the interpretation of trained networks, including neuroimaging Preprint submitted to Computer Methods and Programs in BiomedicineSeptember 7, 2021 preprocessing, quality check, label definition, architecture search, and network training and evaluation. Conclusions We implemented ClinicaDL to bring answers to three common issues encountered by deep learning users who are not always familiar with neuroimaging data: (1) the format and preprocessing of neuroimaging data sets, (2) the contamination of the evaluation procedure by data leakage and (3) a lack of reproducibility. We hope that its use by researchers will allow producing more reliable and thus valuable scientific studies in our field.
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Didier Dormont, Olivier Colliot, APPRIMAGE Study Group • We propose a framework for the automatic... more Didier Dormont, Olivier Colliot, APPRIMAGE Study Group • We propose a framework for the automatic QC of 3D T1w brain MRI for a clinical data warehouse. • We manually labeled 5500 images to train/test different convolutional neural networks. • The automatic approach can identify images which are not proper T1w brain MRIs (e.g. truncated images). • It is able to identify acquisitions for which gadolinium was injected. • It can also accurately identify low quality images.
BMC medical informatics and decision making, Jan 19, 2017
Predicting progression from a stage of Mild Cognitive Impairment to dementia is a major pursuit i... more Predicting progression from a stage of Mild Cognitive Impairment to dementia is a major pursuit in current research. It is broadly accepted that cognition declines with a continuum between MCI and dementia. As such, cohorts of MCI patients are usually heterogeneous, containing patients at different stages of the neurodegenerative process. This hampers the prognostic task. Nevertheless, when learning prognostic models, most studies use the entire cohort of MCI patients regardless of their disease stages. In this paper, we propose a Time Windows approach to predict conversion to dementia, learning with patients stratified using time windows, thus fine-tuning the prognosis regarding the time to conversion. In the proposed Time Windows approach, we grouped patients based on the clinical information of whether they converted (converter MCI) or remained MCI (stable MCI) within a specific time window. We tested time windows of 2, 3, 4 and 5 years. We developed a prognostic model for each t...
Objectifs L'objectif de cette étude était de caractériser, par une approche cerveau-entier à l'éc... more Objectifs L'objectif de cette étude était de caractériser, par une approche cerveau-entier à l'échelle du voxel, le profil d'hypométabolisme en TEP au 18FDG des différents sous-types d'épilepsie du lobe temporal (ELT), comme définis par Stéreo-Électro-EncéphaloGraphie (SEEG) et de déterminer la valeur prédictive de l'examen TEP sur les résultats post-opératoires. Matériels et méthodes Quarante-quatre patients avec ELT pharmacorésistante ont été rétrospectivement inclus après évaluation pré-chirurgicale, permettant de définir : 7 ELT latérales, 18 ELT mésiales, 14 ELT élargies et 16 ELT bilatérales. L'analyse statistique à l'échelle du voxel était réalisée pour chaque sous-groupe de patients en comparaison de 23 sujets sains et une classification individuelle était conduite par validation croisée à partir des clusters extraits. Un index métabolique était, par ailleurs, calculé pour chaque patient à partir du Z-score le plus significatif. Une analyse de régression logistique était utilisée pour estimer les facteurs associés au devenir post-opératoire (classification d'Engel), incluant : l'âge, la durée de la maladie, la fréquence des crises et les résultats de l'IRM et de la TEP. Résultats Différents profils d'hypométabolisme étaient retrouvés, au sein et en dehors de la zone épileptogène, parmi les sous-groupes distincts d'ELT, en comparaison des sujets sains (P < 0,001 ; corrigé pour le cluster). À l'échelle individuelle, la validation croisée montrait une classification satisfaisante des 4 sous-groupes de patients avec une exactitude comprise entre 71,4 et 88,2 %. L'analyse multi-variée montrait que la TEP au 18FDG était l'unique prédicteur significatif du devenir post-opératoire (P = 0,037). Conclusions Cette étude en TEP au 18FDG valide les profils spécifiques d'hypométabolismes des différents sous-types d'ELT définis par le goldstandard de la SEEG et la relation avec le pronostic post-opératoire. Déclaration de liens d'intérêts Les auteurs déclarent ne pas avoir de liens d'intérêts.
Akinetic mustism is a dramatic deficit in spontaneous initiation of voluntary motor and speech ac... more Akinetic mustism is a dramatic deficit in spontaneous initiation of voluntary motor and speech acts, usually secondary to bilateral lesions of the anterior cingulate cortices and supplementary motor areas [1]. Given the obvious limitations of traditional neuropsychological testing in this clinical context, the use of neurophysiological tools such as bedside auditory cognitive event-related potentials (ERPs), recently proven to be relevant to evaluate comatose and vegetative patients [Clin. Neurophysiol. 110 (9) (1999) 1601; News Physiol. Sci. 17 (2002) 38], may constitute an interesting alternative. Here, we present the ERPs of a 38-year-old right-handed woman with severe akinetic mutism recorded in a passive auditory odd-ball paradigm. In spite of this severe clinical state, we could observe the presence of a ''Mismatch Negativity'', and of a larger P300 in rare trials than in frequent ones. By revealing a high level of cognitive integration of environmental auditory information, our study emphasizes the potential clinical relevance of MMN and P300 recordings in akinetic mutism to assess patient cognitive functioning.
Within primary progressive aphasia the logopenic variant remains less understood than the two oth... more Within primary progressive aphasia the logopenic variant remains less understood than the two other main variants, namely semantic and non-fluent progressive aphasia. This may be because of the relatively small number of explored patients and because of the lack of investigations with a comprehensive three-level characterization of cognitive, brain localization and biological aspects. The aim of the present study was to decipher the logopenic variant through a multimodal approach with a large cohort of 19 patients (age 66.5 AE 8.7 years, symptom duration 3.2 AE 0.6 years) using detailed cognitive and linguistic assessments, magnetic resonance imaging and perfusion single-photon emission computed tomography as well as cerebrospinal fluid biomarkers screening for Alzheimer pathology. The linguistic assessment unveiled that language dysfunction is not limited to the typical feature of word finding and verbal working memory impairments but that it extends into the language system affecting to some degree syntactic production, phonological encoding and semantic representations. Perfusion tomography revealed damage of the temporal-parietal junction with a peak of significance in the superior temporal gyrus (Brodmann area 42), and of some less significant prefrontal areas (Brodmann areas 8, 9 and 46), whereas hippocampal cortices were unaffected. Magnetic resonance imaging, which was visually assessed in a larger group of 54 patients with logopenic, non-fluent, semantic variants as well as with posterior cortical atrophy, confirmed that the logopenic variant demonstrates predominant atrophy of left temporal-parietal junction, but that this atrophy pattern has a relatively poor sensitivity and specificity for clinical diagnosis. Finally, the biomarker study revealed that two-thirds of the logopenic patients demonstrated a profile indicative of Alzheimer pathology whereas one-third had a non-Alzheimer profile. Splitting the two groups showed that logopenic aphasia due to probable Alzheimer pathology is a more aggressive variant characterized by more extensive language/cognitive disorders affecting, in addition to lexical processes and verbal working memory, also phoneme sequencing, semantic processing and ideomotor praxis. Concordantly, logopenic aphasia due to probable Alzheimer pathology demonstrated more extensive brain hypoperfusion involving larger regions throughout the inferior parietal, the posterior-superior and the middle temporal cortex. These findings allow for unfolding logopenic aphasia into two subvariants differing by disease severity, lesion nature and lesion distribution, which has important implications for diagnosis, patient management and for potential future trials with
Early identification of patients at risk of space-occupying &amp;amp;amp;amp;amp;amp;amp;amp;... more Early identification of patients at risk of space-occupying &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;malignant&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; middle cerebral artery (MCA) infarction (MMI) is needed to enable timely decision for potentially life-saving treatment such as decompressive hemicraniectomy. We tested the hypothesis that acute stroke magnetic resonance imaging (MRI) predicts MMI within 6 hours of stroke onset. In a prospective, multicenter, observational cohort study patients with acute ischemic stroke and MCA main stem occlusion were studied by MRI including diffusion-weighted imaging (DWI), perfusion imaging (PI), and MR-angiography within 6 hours of symptom onset. Multivariate regression analysis was used to identify clinical and imaging predictors of MMI. Of 140 patients included, 27 (19.3%) developed MMI. The following parameters were identified as independent predictors of MMI: larger acute DWI lesion volume (per 1 ml odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.06; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), combined MCA + internal carotid artery occlusion (5.38, 1.55-18.68; p = 0.008), and severity of neurological deficit on admission assessed by the National Institutes of Health Stroke Scale score (per 1 point 1.16, 1.00-1.35; p = 0.053). The prespecified threshold of a DWI lesion volume &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;82 ml predicted MMI with high specificity (0.98, 95% CI 0.94-1.00), negative predictive value (0.90, 0.83-0.94), and positive predictive value (0.88, 0.62-0.98), but sensitivity was low (0.52, 0.32-0.71). Stroke MRI on admission predicts malignant course in severe MCA stroke with high positive and negative predictive value and may help in guiding treatment decisions, such as decompressive surgery. In a subset of patients with small initial DWI lesion volumes, repeated diagnostic tests are required.
The physiopathologic bases underlying the signal intensity changes and reduced diffusibility obse... more The physiopathologic bases underlying the signal intensity changes and reduced diffusibility observed in prion diseases (TSEs) are still poorly understood. We evaluated the interest of MRS combined with DWI both as a diagnostic tool and a way to understand the mechanism underlying signal intensity and ADC changes in this setting. MATERIALS AND METHODS: We designed a prospective study of multimodal MR imaging in patients with suspected TSEs. Forty-five patients with a suspicion of TSE and 11 age-matched healthy volunteers were included. The MR imaging protocol included T1, FLAIR, and DWI sequences. MRS was performed on the cerebellum, pulvinar, right lenticular nucleus, and frontal cortex. MR images were assessed visually, and ADC values were calculated. RESULTS: Among the 45 suspected cases, 31 fulfilled the criteria for probable or definite TSEs (19 sCJDs, 3 iCJDs, 2 vCJDs, and 7 genetic TSEs); and 14 were classified as AltDs. High signals in the cortex and/or basal ganglia were observed in 26/31 patients with TSEs on FLAIR and 29/31 patients on DWI. In the basal ganglia, high DWI signals corresponded to a decreased ADC. Metabolic alterations, increased mIns, and decreased NAA were observed in all patients with TSEs. ADC values and metabolic changes were not correlated; this finding suggests that neuronal stress (vacuolization), neuronal loss, and astrogliosis do not alone explain the decrease of ADC. CONCLUSIONS: MRS combined with other MR imaging is of interest in the diagnosis of TSE and provides useful information for understanding physiopathologic processes underlying prion diseases. ABBREVIATIONS: ADC ϭ apparent diffusion coefficient; AltD ϭ alternative diagnosis; Avg ϭ average; C (or c) ϭ control; Cho ϭ choline; CJD ϭ Creutzfeldt-Jakob disease; Cr ϭ creatine; DWI ϭ diffusionweighted imaging; EEG ϭ electroencephalograph; FFI ϭ fatal familial insomnia; FLAIR ϭ fluid-attenuated inversion recovery; GABA ϭ gamma-aminobutyric acid; gCJD ϭ genetic CJD; Glx ϭ glutamineglutamate-GABA; GSS ϭ Gerstmann Strausser Sheinker syndrome; iCJD ϭ iatrogenic CJD; mIns ϭ myo-inositol; MM ϭ methionine homozygosity (PRNP: genotype at codon 129); MRS ϭ MR spectroscopy; MRI ϭ MR imaging; MV ϭ methionine-valine heterozygosity (PRNP: genotype at codon 129); NA ϭ data not available; NAA ϭ N-acetylaspartate; NS ϭ not significant or nonspecific slow waves; P (or p) ϭ patient; PRNP ϭ genotype at codon 129; PrP ϭ prion protein or persistent plexus gene; S ϭ sum of metabolites; sCJD ϭ sporadic CJD; TSE ϭ human transmissible spongiform encephalopathy; vCJD ϭ variant CJD; VV ϭ valine homozygosity (PRNP: genotype at codon 129)
Anne Bertrand passed away on March 2nd 2018. She was in a touring-skiers group led by a guide and... more Anne Bertrand passed away on March 2nd 2018. She was in a touring-skiers group led by a guide and swept by an avalanche in the French Alps. This paper is a tribute to Anne and an attempt, by some of her closest colleagues, to provide an overview of her major contributions. Anne Bertrand was a rising star of the neuroimaging community who traced innovative paths at the interface of basic science and clinical neuroradiology. From the very beginning of her career, she had been interested in the cross-fertilization between research and medical practice. After an MD and a specialization in neuroradiology, she prepared a PhD in preclinical imaging at the French Atomic Energy Commission (CEA) and at New York University. She was then appointed as Senior Neuroradiologist (at the Pitié-Salpêtrière and then Saint-Antoine Hospital in Paris) and Associate Professor (Sorbonne University). Simultaneously, she continued to develop her research activities in the ARAMIS Laboratory at the Brain and Spinal Cord Institute (ICM). Her main field of interest was neuroimaging of dementias. In a short time, she made important and exceptionally diverse contributions to the understanding, detection, diagnosis and tracking of these disorders (including Alzheimer's disease and fronto-temporal lobar degeneration) using advanced multimodal neuroimaging techniques. They will be a source of inspiration for all of us. Anne was not only an outstandingly bright scientist but also enlightening by her personal qualities: joy, openness, kindness and generosity.
Objective: To describe a reversible neurological condition resembling a crossed midbrain syndrome... more Objective: To describe a reversible neurological condition resembling a crossed midbrain syndrome resulting from high frequency stimulation (HFS) in the midbrain. Methods: Postoperative evaluation of quadripolar electrodes implanted in the area of the subthalamic nucleus of 25 patients with Parkinson's disease (PD) successfully treated by HFS. Results: Four of the 25 patients experienced reversible acute diplopia, with dystonic posture and tremor in the contralateral upper limb when the white matter between the red nucleus and the substantia nigra was stimulated. The motor signs resembled those caused by lesions of the red nucleus. The ipsilateral resting eye position was "in and down" (three patients) or "in" (one patient). Enophthalmos was seen. Abduction was impaired and vertical eye movements were limited, but adduction was spared. The movements of the controlateral eye were normal. The ocular signs could be best explained by sustained hyperactivity of the extrinsic oculomotor nerve. Simultaneous tonic contraction of the superior rectus, the inferior rectus, and inferior oblique may cause the enophthalmos and partial limitation of upward and downward eye movements. Antagonist tonic contraction of the ipsilateral medial rectus severely impairs abduction. Conclusion: This crossed midbrain syndrome, possibly resulting from simultaneous activation of oculomotor nerve and lesion-like inhibition of the red nucleus suggests that high frequency stimulation has opposite effects on grey and white matter.
To report a method of electrode implantation in the ventralis intermedius nucleus of the thalamus... more To report a method of electrode implantation in the ventralis intermedius nucleus of the thalamus for the treatment of tremor using a 3-D stereotactic MR imaging technique. METHODS: Five patients (three men and two women; mean age, 59 years) with medically refractory tremor had intrathalamic implantation of a stimulating electrode. Stereotactic MR imaging was performed on a 1.5-T unit equipped with an MR-compatible Leksell G stereotactic frame fixed to the patient's head. Calculation of the coordinates of the theoretical target was based on the coordinates of the anterior commissure, the posterior commissure, and the midline sagittal plane as determined via stereotactic MR imaging. During the surgical procedure, the best position for the stimulating electrode was determined by electrophysiological and clinical studies. Postoperative MR control studies were done in all cases to verify the position of the electrode. RESULTS: Stereotactic MR imaging allowed precise implantation of the stimulating electrode in all patients. Electrode stimulation produced a 90% reduction of the tremor in two patients, an 80% and 70% reduction in one patient each, and a persistent microthalamotomy-like effect in the fifth patient. Examination of the MR control studies showed that mean error in the positioning of the electrodes was 0.77 Ϯ 0.6 mm (mean Ϯ SD) in the x direction and 0.80 Ϯ 1.02 mm in the y direction. CONCLUSION: Although our series is relatively small, the precision achieved with stereotactic MR imaging proves that it can be used with confidence for precise functional neurosurgical procedures.
Background: High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment... more Background: High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for advanced forms of Parkinson disease. Postoperative improvement of motor parkinsonian disability is known to depend on patient selection and surgical targeting. Objective: To determine which clinical and electrophysiological variables evaluated during the operation predict the postoperative clinical outcome of patients with Parkinson disease treated by bilateral high-frequency stimulation of the STN. Methods: Intraoperative clinical and electrophysiological data obtained in 41 patients with Parkinson disease who underwent bilateral implantation of electrodes for STN stimulation were correlated with the improvement in parkinsonian disability assessed 6 months after the operation. Results: The extent of STN neuronal activity recorded along the trajectory of the therapeutic electrode had no effect on the postoperative clinical outcome. The intraoperative improvement in segmental akinesia, but not rigidity, was predictive of the postoperative improvement in parkinsonian motor disability and reduction in daily levodopaequivalent dosage. Parkinsonian motor disability scores assessed after surgery were lower in patients with intraoperative stimulation-induced dyskinesias than in those without stimulation-induced dyskinesias. Conclusion: The improvement of segmental akinesia and the observation of dyskinesias provoked by stimulation during the operation predict the best postoperative effects of bilateral STN stimulation on parkinsonian motor disability.
Objectives QyScore® is an imaging analysis tool certified in Europe (CE marked) and the US (FDA c... more Objectives QyScore® is an imaging analysis tool certified in Europe (CE marked) and the US (FDA cleared) for the automatic volumetry of grey and white matter (GM and WM respectively), hippocampus (HP), amygdala (AM), and white matter hyperintensity (WMH). Here we compare QyScore® performances with the consensus of expert neuroradiologists. Methods Dice similarity coefficient (DSC) and the relative volume difference (RVD) for GM, WM volumes were calculated on 50 3DT1 images. DSC and the F1 metrics were calculated for WMH on 130 3DT1 and FLAIR images. For each index, we identified thresholds of reliability based on current literature review results. We hypothesized that DSC/F1 scores obtained using QyScore® markers would be higher than the threshold. In contrast, RVD scores would be lower. Regression analysis and Bland–Altman plots were obtained to evaluate QyScore® performance in comparison to the consensus of three expert neuroradiologists. Results The lower bound of the DSC/F1 conf...
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. How serious is data leakage in deep learning studies on Alzheimer’s disease classification? Junhao Wen, Elina Thibeau-Sutre, Jorge Samper-Gonzalez, Alexandre Routier, Simona Bottani, Didier Dormont, Stanley Durrleman , Olivier Colliot, Ninon Burgos
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Alzheimer's & Dementia: Translational Research & Clinical Interventions, 2021
Introduction: We aim to understand how patients with Alzheimer's disease (AD) are treated by iden... more Introduction: We aim to understand how patients with Alzheimer's disease (AD) are treated by identifying in a longitudinal fashion the late-life changes in patients' medical history that precede and follow AD diagnosis. Methods: We use prescription history of 34,782 patients followed between 1996 and 2019 by French general practitioners. We compare patients with an AD diagnosis, patients with mild cognitive impairment (MCI), and patients free of mental disorders. We use a generalized mixed-effects model to study the longitudinal changes in the prescription of eight drug types for a period 15 years before diagnosis and 10 years after. Results: In the decades preceding diagnosis, we find that future AD patients are treated significantly more than MCI patients with most psychotropic drugs and that most studied drugs are increasingly prescribed with age. At the time of diagnosis, all psychotropic drugs except benzodiazepines show a significant increase in prescription, while other drugs are significantly less prescribed. In the 10 years after diagnosis, nearly all categories of drugs are less and less prescribed including antidementia drugs. Discussion: Pre-diagnosis differences between future AD patients and MCI patients may indicate that subtle cognitive changes are recognized and treated as psychiatric symptoms. The disclosure of AD diagnosis drastically changes patients' care, priority being given to the management of psychiatric symptoms. The decrease of all prescriptions in the late stages may reflect treatment discontinuation and simplification of therapeutic procedures. This study therefore provides new insights into the medical practices for management of AD.
Preoperative embolization of Hypervascular Spinal Metastases (HSM) is efficient to reduce periope... more Preoperative embolization of Hypervascular Spinal Metastases (HSM) is efficient to reduce perioperative bleeding. However, intra-arterial digital subtraction angiography (IA-DSA) must confirm the hypervascular nature and rule out spinal cord arterial feeders. This study aimed to evaluate the reliability and accuracy of Time Resolved Contrast Enhanced Magnetic Resonance Angiography (TR-CE-MRA) in assessing HSM prior to embolization. Methods All consecutive patients referred for preoperative embolization of an HSM were prospectively included. TR-CE-MRA sequences and selective IA-DSA were performed prior to embolization. Two readers independently reviewed imaging data to grade tumour vascularity (using a 3grade and a dichotomized "yes vs no" scale) and identify the arterial supply of the spinal cord. Interobserver and intermodality agreements were estimated using kappa statistics. Results Thirty patients included between 2016 and 2019 were assessed for 55 levels.
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