Safety and efficacy of transvenous embolization of cerebrospinal fluid-venous fistula in patients with spontaneous intracranial hypotension

BACKGROUND

Transvenous embolization is a recent treatment strategy for cerebrospinal fluid-venous fistulas (CSFVF), which are associated with spontaneous intracranial hypotension (SIH).

METHODS

Participants were selected from a prospective database on patients with CSFVF that received transvenous Onyx embolization. All patients underwent a brain magnetic resonance imaging (MRI) before and after embolization with MRI follow-up performed at least 3 months after treatment. Clinical and MRI results after treatment were described.

RESULTS

Twenty-one consecutive patients (median age 63 years, IQR = 58-71; females: 15/21 = 71.5%) with 30 CSFVF were included. Most lesions were situated between T9 and L1 (19/30 = 63%), 70% were right-sided, and 38% of the patients had multiples fistulas. Embolization was successful in all cases. The mean MRI SIH score before and after treatment was 6 (±2.5) and 1.4 (±1.6), respectively (p < 0.0001). Twenty patients (90%) experienced improvement of their initial condition, of which 67% reported complete clinical recovery. The mean HIT-6 score decreased from 67 (±15) to 38 (±9) (p < 0.0001), the mean amount of monthly headache days from 23.5 (±10) and 3.2 (±6.6) (p < 0.0001), the visual assessment scale (VAS) for headache severity from 8 (±1.9) to 1.2 (±2) (p < 0.0001), and the mean VAS for perception quality of life improved from 2.6 (±2.5) to 8.6 (±1.8) (p < 0.0001). There were no major complications. The suspected rebound headache rate after treatment was 33%.

CONCLUSION

Transvenous embolization of CSFVF allowed high rates of clinical improvement with no morbidity related to the treatment.

Evaluation of a nnU-Net type automated clinical volumetric tumor segmentation tool for diffuse low-grade glioma follow-up

BACKGROUND AND PURPOSE

Diffuse low-grade gliomas (DLGG) are characterized by a slow and continuous growth and always evolve towards an aggressive grade. Accurate prediction of the malignant transformation is essential as it requires immediate therapeutic intervention. One of its most precise predictors is the velocity of diameter expansion (VDE). Currently, the VDE is estimated either by linear measurements or by manual delineation of the DLGG on T2 FLAIR acquisitions. However, because of the DLGG's infiltrative nature and its blurred contours, manual measures are challenging and variable, even for experts. Therefore we propose an automated segmentation algorithm using a 2D nnU-Net, to 1) gain time and 2) standardize VDE assessment.

MATERIALS AND METHODS

The 2D nnU-Net was trained on 318 acquisitions (T2 FLAIR & 3DT1 longitudinal follow-up of 30 patients, including pre- & post-surgery acquisitions, different scanners, vendors, imaging parameters…). Automated vs. manual segmentation performance was evaluated on 167 acquisitions, and its clinical interest was validated by quantifying the amount of manual correction required after automated segmentation of 98 novel acquisitions.

RESULTS

Automated segmentation showed a good performance with a mean Dice Similarity Coefficient (DSC) of 0.82±0.13 with manual segmentation and a substantial concordance between VDE calculations. Major manual corrections (i.e., DSC<0.7) were necessary only in 3/98 cases and 81% of the cases had a DSC>0.9.

CONCLUSION

The proposed automated segmentation algorithm can successfully segment DLGG on highly variable MRI data. Although manual corrections are sometimes necessary, it provides a reliable, standardized and time-winning support for VDE extraction to asses DLGG growth.

Low levels of peripheral blood activated and senescent T cells characterize people with HIV-1-associated neurocognitive disorders

Background

HIV infection induces a 75% increase in the risk of developing neurocognitive impairment (NCI), which has been linked to immune activation. We therefore looked for immune activation markers correlating with NCI.

Method

Sixty-five people aged 55-70 years living with controlled HIV-1 infection were enrolled in the study and their neurocognitive ability was assessed according to the Frascati criteria. Fifty-nine markers of T4 cell, T8 cell, NK cell, and monocyte activation, inflammation and endothelial activation were measured in their peripheral blood. White matter hyperintensities (WMH) were identified by magnetic resonance imaging. Double hierarchical clustering was performed for the activation markers and 240 patients including the 65 whose neurocognitive performance had been evaluated.

Results

Thirty-eight percent of volunteers presented NCI. Twenty-four percent of them were asymptomatic and fourteen percent had a mild disorder. Strikingly, activated (HLA-DR+) as well as senescent (CD57+CD28-CD27±) T4 cells and T8 cells were less prevalent in the peripheral blood of participants with NCI than in participants without the disorder. Accordingly, the percentage of HLA-DR+ T4 cells was lower in volunteers with periventricular and deep WMH. The double hierarchical clustering unveiled six different immune activation profiles. The neurocognitive performances of participants with two of these six profiles were poor. Here again, these two profiles were characterized by a low level of T4 and T8 cell activation and senescence.

Conclusion

Our observation of low circulating levels of activated and senescent T cells in HIV-1 patients with NCI raises the interesting hypothesis that these lymphocytes may be recruited into the central nervous system.

Functional PET Neuroimaging in Consciousness Evaluation: Study Protocol

Ensuring a robust and reliable evaluation of coma deepness and prognostication of neurological outcome is challenging. We propose to develop PET neuroimaging as a new diagnostic and prognosis tool for comatose patients using a recently published methodology to perform functional PET (fPET). This exam permits the quantification of task-specific changes in neuronal metabolism in a single session. The aim of this protocol is to determine whether task-specific changes in glucose metabolism during the acute phase of coma are able to predict recovery at 18 months. Participation will be proposed for all patients coming for a standard PET-CT in our center in order to evaluate global cerebral metabolism during the comatose state. Legally appointed representative consent will be obtained to slightly modify the exam protocol: (1) ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) bolus plus continuous infusion instead of a simple bolus and (2) more time under camera to perform dynamic acquisition. Participants will undergo a 55-min fPET session with a 20% bolus + 80% infusion protocol. Two occurrences of three block (5-min rest, 10-min auditory stimulation and 10-min emotional auditory stimulation) will be performed after reaching equilibrium of FDG arterial concentration. We will compare the regional brain metabolism at rest and during the sessions of auditory and emotional auditory stimulation to search for a determinant of coma recovery (18 months of follow-up after the exam). Emotional auditory stimulation should induce an activation of: the auditory cortex, the consciousness areas and the neural circuitry for emotion (function to coma deepness). An activation analysis will be carried out to highlight regional brain activation using dedicated custom-made software based on Python statistical and image processing toolboxes. The association between activation levels and the Coma Recovery Scale-Revisited (CRS-R) will be assessed using multivariate analysis. If successful, the results from this study will help improve coma prognosis evaluation based on the pattern of neuronal metabolism at the onset of the pathology. The study protocol, rationale and methods are described in this paper.

Precuneal gliomas promote behaviorally relevant remodeling of the functional connectome

OBJECTIVE

The precuneus hosts one of the most complex patterns of functional connectivity in the human brain. However, due to the extreme rarity of neurological lesions specifically targeting this structure, it remains unknown how focal damage to the precuneus may impact resting-state functional connectivity (rsFC) at the brainwide level. The aim of this study was to investigate glioma-induced rsFC modulations and to identify patterns of rsFC remodeling that accounted for the maintenance of cognitive performance after awake-guided surgical excision.

METHODS

In a unique series of patients with IDH1-mutated low-grade gliomas (LGGs) infiltrating the precuneus who were treated at a single neurosurgical center (Montpellier University Medical Center, 2014-2021), the authors gauged the dynamic modulations induced by tumors on rsFC in comparison with healthy participants. All patients received a preoperative resting-state functional MRI and underwent operation guided by awake cognitive mapping. Connectome multivariate pattern analysis (MVPA), seed-network analysis, and graph theoretical analysis were conducted and correlated to executive neurocognitive scores (i.e., phonological and semantic fluencies, Trail-Making Test [TMT] parts A and B) obtained 3 months after surgery.

RESULTS

Seventeen patients with focal precuneal infiltration were selected (mean age 38.1 ± 11.2 years) and matched to 17 healthy participants (mean age 40.5 ± 10.4 years) for rsFC analyses. All patients underwent awake cognitive mapping, allowing total resection (n = 3) or subtotal resection (n = 14), with a mean extent of resection of 90.6% ± 7.3%. Using MVPA (cluster threshold: p-false discovery rate corrected < 0.05, voxel threshold: p-uncorrected < 0.001), remote hotspots with significant rsFC changes were identified, including both insulas, the anterior cingulate cortex, superior sensorimotor cortices, and both frontal eye fields. Further seed-network analyses captured 2 patterns of between-network redistribution especially involving hyperconnectivity between the salience, visual, and dorsal attentional networks. Finally, the global efficiency of the salience-visual-dorsal attentional networks was strongly and positively correlated to 3-month postsurgical scores (n = 15) for phonological fluency (r15 = 0.74, p = 0.0027); TMT-A (r15 = 0.65, p = 0.012); TMT-B (r15 = 0.70, p = 0.005); and TMT-B-A (r15 = 0.62, p = 0.018).

CONCLUSIONS

In patients with LGGs infiltrating the precuneus, remote and distributed functional connectivity modulations in the preoperative setting are associated with better maintenance of cognitive performance after surgery. These findings provide a new vision of the mechanistic principles underlying neural plasticity and cognitive compensation in patients with LGGs.

Impact of multidomain preventive strategies on functional brain connectivity in older adults with cognitive complaint: Subset from the Montpellier center of the ancillary MAPT-MRI study

Introduction

The impact of multi-domain preventive interventions on older adults, in particular on those with higher risk to develop Alzheimer's disease (AD), could be beneficial, as it may delay cognitive decline. However, the precise mechanism of such positive impact is not fully understood and may involve brain reserve and adaptability of brain functional connectivity (FC).

Methods

To determine the effect of multidomain interventions (involving physical activity, cognitive training, nutritional counseling alone or in combination with omega-3 fatty acid supplementation and vs. a placebo) on the brain, longitudinal FC changes were assessed after 36 months of intervention on 100 older adults (above 70 year-old) with subjective cognitive complaints.

Results

No global change in FC was detected after uni or multidomain preventive interventions. However, an effect of omega-3 fatty acid supplementation dependent on cognitive decline status was underlined for frontoparietal, salience, visual and sensorimotor networks FC. These findings were independent of the cortical thickness and vascular burden.

Discussion

These results emphasize the importance of patient stratification, based on risk factors, for preventive interventions.

The effect of early trauma on suicidal vulnerability depends on fronto-insular sulcation

Improving our understanding of pathophysiology of suicidal behavior (SB) is an important step for prevention. Assessment of suicide risk is based on socio-demographic and clinical risk factors with a poor predictivity. Current understanding of SB is based on a stress-vulnerability model, whereby early-life adversities are predominant. SB may thus result from a cascade of developmental processes stemming from early-life abuse and/or neglect. Some cerebral abnormalities, particularly in fronto-limbic regions, might also provide vulnerability to develop maladaptive responses to stress, leading to SB. We hypothesized that SB is associated with interactions between early trauma and neurodevelopmental deviations of the frontal and insular cortices. We recruited 86 euthymic women, including 44 suicide attempters (history of depression and SB) and 42 affective controls (history of depression without SB). The early development of prefrontal cortex (PFC) and insula was inferred using 3D magnetic resonance imaging-derived regional sulcation indices, which are indirect markers of early neurodevelopment. The insula sulcation index was higher in emotional abused subjects; among those patients, PFC sulcation index was reduced in suicide attempters, but not in affective controls. Such findings provide evidence that SB likely traced back to early stages of brain development in interaction with later environmental factors experienced early in life.

Effects of preventive interventions on neuroimaging biomarkers in subjects at-risk to develop Alzheimer's disease: A systematic review

Alzheimer's Disease (AD) is a multifactorial and complex neurodegenerative disorder. Some modifiable risk factors have been associated with an increased risk of appearance of the disease and/or cognitive decline. Preventive clinical trials aiming at reducing one or combined risk factors have been implemented and their potential effects assessed on cognitive trajectories and on AD biomarkers. However, the effect of interventions on surrogate markers, in particular imaging biomarkers, remains poorly understood. We conducted a review of the literature and analyzed 43 interventional studies that included physical exercise, nutrition, cognitive training or multidomain interventions, and assessed various brain imaging biomarkers, to determine the effects of preventive interventions on imaging biomarkers for subjects at-risk to develop AD. Deciphering the global and regional brain effect of each and combined interventions will help to better understand the interplay relationship between multimodal interventions, cognition, surrogate brain markers, and to better design primary and secondary outcomes for future preventive clinical trials. Those studies were pondered using generally-admitted quality criteria to reveal that interventions may affect the brain of patients with cognitive impairment rather than those without cognitive impairment thus indicating that particular care should be taken when selecting individuals for interventions. Additionally, a majority of the studies concurred on the effect of the interventions and particularly onto the frontal brain areas.

Glucometabolic Changes Are Associated with Structural Gray Matter Alterations in Prodromal Dementia

BACKGROUND

Glucometabolic changes, such as high glycemic load (GL) diet and insulin resistance (IR), are potential risk factor of Alzheimer's disease (AD). Yet, the effect of these factors on brain alterations that contribute to AD pathology has not been clearly demonstrated.

OBJECTIVE

We aimed to assess the relationship of GL and IR with gray matter volumes involved in prodromal dementia.

METHODS

GL and Triglyceride-Glucose (TyG) index, an IR surrogate marker, were calculated in 497 participants who underwent magnetic resonance imaging (MRI). The gray matter volumes most related to prodromal dementia/mild cognitive impairment (diagnosed in 18/158 participants during the 7-year follow-up) were identified using a data-driven machine learning algorithm.

RESULTS

Higher GL diet was associated with reduced amygdala volume. The TyG index was negatively associated with the hippocampus, amygdala, and putamen volumes.

CONCLUSION

These results suggest that GL and IR are associated with lower gray matter volumes in brain regions involved in AD pathology.

Prefrontal activity during experimental ostracism and daily psychache in suicide attempters

BACKGROUND

Suicidal behaviors can result from a complex interaction between social stressors and individual vulnerability. Evidence suggests a specific neural processing of social cues in suicide attempters without knowledge of how it relates to real-world experiences.

OBJECTIVE

To investigate the association between brain activity during experimental social exclusion (measured by functional MRI) and psychological pain in daily life (assessed by Ecological Momentary Assessment) in patients with a lifetime history of suicide attempt.

METHODS

Thirty-three euthymic females with a history of a major depressive episode were recruited: 13 suicide attempters and 20 affective controls (no history of suicide attempt). Functional MRI scans were acquired while participants played the Cyberball game, a validated social exclusion paradigm. After fMRI, participants completed EMA for a one-week period. Five times per day, they were asked to rate their psychological pain, hopelessness and the negativity of daily events. EMA indices (psychological pain, hopelessness and their interaction with negative events) were correlated with cerebral activations using a ROI approach (orbitofrontal, dorsal and ventrolateral prefrontal cortices, anterior cingulate cortex and insula) in each group.

RESULTS

We found a negative correlation between daily ratings of psychological pain and orbitofrontal activation for exclusion versus inclusion during the Cyberball game in suicide attempters but not in affective controls. We did not find correlations between cerebral activation and daily hopelessness ratings.

LIMITATIONS

Small sample size CONCLUSION: Scanner-based orbitofrontal activity during social exclusion relates to psychological pain in daily life which participates in suicide risk among vulnerable individuals.

Cerebral Vasoreactivity as an Indirect MRI Marker of White Matter Tracts Alterations in Multiple Sclerosis

Patients with multiple sclerosis (MS) show a diffuse cerebral perfusion decrease, presumably related to multiple metabolism and vascular alterations. It is assumed that white matter fiber alterations cause a localized cerebral vasoreactivity (CVR) disruption through astrocytes metabolism alteration, leading to hypoperfusion. We proposed to (1) evaluate the CVR disruptions in MS, (2) in relation to white matter lesions and (3) compare CVR disruptions maps with standard imaging biomarkers. Thirty-five MS patients (10 progressive, 25 relapsing-remitting) and 22 controls underwent MRI with hypercapnic challenge, DTI imaging and neuropsychological assessment. Areas with disrupted CVR were assessed using a general linear model. Resulting maps were associated with clinical scores, compared between groups, and related to DTI metrics and white matter lesions. MS patients showed stronger disrupted CVR within supratentorial white matter, linking the left anterior insula to both the precentral gyrus and the right middle and superior frontal gyrus through the corpus callosum (P < 0.05, FWE corrected). Patient's verbal intellectual quotient was negatively associated with a pathway linking both hippocampi to the ispilateral prefrontal cortex (P < 0.05, FWE corrected). Disrupted CVR maps unrelated to DTI metrics and white matter lesions. We have demonstrated for the first time that white matter alterations can be indirectly identified through surrounding vessel alterations, and are related to clinical signs of MS. This offers a new, likely independent marker to monitor MS and supports a mediator role of the astrocytes in the fibers/vessels relationship.

Task- and Rest-based Functional Brain Connectivity in Food-related Reward Processes among Healthy Adolescents

It is known that the nucleus accumbens, orbitofrontal cortex and insula play a role in food-related reward processes. Although their interconnectedness would be an ideal topic for understanding food intake mechanisms, it nevertheless remains unclear especially in adolescent. Therefore, this study aims to investigate the effect of hunger on functional connectivity in healthy adolescents using task- and rest-based imaging. Fifteen participants underwent two MRI sessions, pre-lunch (hunger) and post-lunch (satiety), including food cue task and resting-state. During task- and rest-based imaging, functional connectivity was greater when hungry as opposed to satiated between the right posterior insula/nucleus accumbens, suggesting involvement of salient interoceptive stimuli signals. During task-based imaging, an increase was observed in functional connectivity when hungry as opposed to satiated between the medial and lateral orbitofrontal cortex which contributes to the perception of food deprivation as a frustration. A decrease was identified when hungry as opposed to satiated in functional connectivity in the right anterior orbitofrontal/accumbens and posterior insula/medial orbitofrontal cortices reflecting suppression of the affective and sensorial information. Conversely, functional connectivity was increased during aversive stimuli between the right medial orbitofrontal cortex and right posterior insula when hungry as opposed to satiated. This suggests that the value of valence could occur in the shift in connectivity between these two regions. In addition, during rest-based imaging, a left-sided lateralization was reported (accumbens/lateral orbitofrontal and accumbens/posterior insula) when hungry as opposed to satiated which may represent changes in internal state due to focus on the benefit of an upcoming meal.

DWI cerebellar infarct volume as predictor of outcomes after endovascular treatment of acute basilar artery occlusion

BACKGROUND

Preprocedural predictors of outcome in patients with acute basilar artery occlusion (ABAO) who have undergone endovascular treatment (EVT) remain controversial. Our aim was to determine if pre-EVT diffusion-weighted imaging cerebellar infarct volume (CIV) is a predictor of 90-day outcomes.

METHODS

We analyzed consecutive MRI-selected endovascularly treated patients with ABAO within the first 24 hours after symptom onset. Successful reperfusion was defined as a modified Thrombolysis in Cerebral Infarction score of 2b-3. Using the initial MRI, baseline CIV was calculated in mL on an apparent diffusion coefficient map reconstruction (Olea Sphere software). CIV was analyzed in univariate and multivariable models as a predictor of 90-day functional independence (modified Rankin Scale (mRS) 0-2) and mortality. According to receiver operating characteristic (ROC) analysis, the optimal cut-off was determined by maximizing the Youden index to evaluate the prognostic value of CIV.

RESULTS

Of the 110 MRI-selected patients with ABAO, 64 (58.18%) had a cerebellar infarct. The median CIV was 9.6 mL (IQR 2.7-31.4). Successful reperfusion was achieved in 81.8% of the cases. At 90 days the proportion of patients with mRS ≤2 was 31.8% and the overall mortality rate was 40.9%. Baseline CIV was significantly associated with 90-day mRS 0-2 (p=0.008) in the univariate analysis and was an independent predictor of 90-day mortality (adjusted OR 1.79, 95% CI 1.25 to 2.54, p=0.001). The ROC analysis showed that a CIV ≥4.7 mL at the initial MRI was the optimal cut-off to discriminate patients with a higher risk of death at 90 days (area under the ROC curve (AUC)=0.74, 95% CI 0.61 to 0.87, sensitivity and specificity of 87.9% and 58.1%, respectively).

CONCLUSIONS

In our series of MRI-selected patients with ABAO, pre-EVT CIV was an independent predictor of 90-day mortality. The risk of death was increased for baseline CIV ≥4.7 mL.

Prefrontal activation in suicide attempters during decision making with emotional feedback

Emotional feedback, such as faces showing emotions, can influence decision making. Decision making and emotional face processing, mainly mediated by the prefrontal and cingulate cortices, are impaired in suicide attempters. Here, we used functional MRI (fMRI) to study prefrontal activation in suicide attempters during a modified version of the Iowa Gambling Task (IGT) that included emotional face feedback. We randomly distributed the 116 euthymic women (n = 45 suicide attempters, n = 41 affective controls with history of depression without suicide attempt, and n = 30 healthy controls) included in the study in three emotional IGT groups: concordant (safe and risky choices followed by happy and angry faces, respectively), discordant (safe and risky choices followed by angry and happy faces, respectively), and neutral condition (safe and risky choices followed by neutral faces). Considering the two IGT phases (ambiguous and risky), we then analyzed five regions of interest during the risky vs. safe choices: orbitofrontal (OFC), anterior cingulate (ACC), ventrolateral (VLPFC), medial (MPFC) and dorsal prefrontal (DPFC) cortices. We found: (1) impaired decision making and increased DPFC and OFC activation in suicide attempters vs. controls in the discordant condition during the risky phase; (2) reduced VLPFC activation in suicide attempters in the concordant condition during the ambiguous phase; and (3) decreased OFC, ACC and DPFC activation in both control groups in the concordant condition during the ambiguous phase. Suicide attempters showed prefrontal alterations during reward-learning decision making with emotional feedback. Suicide attempters may guide their decisions to avoid social negative feedback despite the expected outcome.

Serum GFAP in multiple sclerosis: correlation with disease type and MRI markers of disease severity

Neurofilament light chain (NfL) has been demonstrated to correlate with multiple sclerosis disease severity as well as treatment response. Nevertheless, additional serum biomarkers are still needed to better differentiate disease activity from disease progression. The aim of our study was to assess serum glial fibrillary acid protein (s-GFAP) and neurofilament light chain (s-NfL) in a cohort of 129 multiple sclerosis (MS) patients. Eighteen primary progressive multiple sclerosis (PPMS) and 111 relapsing remitting MS (RRMS) were included. We showed that these 2 biomarkers were significantly correlated with each other (R = 0.72, p < 0.001). Moreover, both biomarkers were higher in PPMS than in RRMS even if multivariate analysis only confirmed this difference for s-GFAP (130.3 ± 72.8 pg/ml vs 83.4 ± 41.1 pg/ml, p = 0.008). Finally, s-GFAP was correlated with white matter lesion load and inversely correlated with WM and GM volume. Our results seem to confirm the added value of s-GFAP in the context of multiple sclerosis.

Quantitative assessment of near-infrared spectroscopy time course under hypercapnia using an a priori model-based fitting

BACKGROUND

Partial arterial pressure of carbon dioxide (CO₂) modulates cerebral blood flow through a vasoreactivity mechanism. Near infrared spectroscopy (NIRS) can be used to record these changes in cerebral hemodynamics. However, no laterality comparison of the NIRS signal has been performed despite being a prerequisite for the use of such a method in a vasoreactivity monitoring context. We propose to investigate the NIRS signal laterality in response to a CO₂-inhalation-based hypercapnia paradigm in healthy volunteers.

METHODS

Eleven healthy volunteers (6 women, 5 men, mean age: 31 ± 11) underwent a 3-block-design inhalation paradigm: normoxia (5min, "baseline") - hypercapnia (2min, "stimulation") - normoxia (5min, "post-stimulation"). NIRS signal was measured using a two-channel oximeter (INVOS 5100C, Medtronic, USA) with sensors placed symmetrically on both left and right sides on each subject's forehead. Additional heart rate (HR) monitoring was performed simultaneously. Based on the NIRS mean signal pattern, an a priori model of parametric identification was applied for each channel to quantify parameters of interest (amplitude, time delay, excitation and post-stimulation time) for each inhalation block.

RESULTS

HR increased significantly during the stimulation block. The quality of the model was satisfactory: mean absolute errors between modeled and experimental signals were lower than the resolution of the device. No significant lateralization was found between left and right values of most of the parameters.

CONCLUSION

Due to the lack of lateralization, this parametric identification of NIRS responses to hypercapnia could bring light to a potential asymmetry and be used as a biomarker in patients with cerebrovascular diseases.

Retinal vascular fractal dimension and cerebral blood flow, a pilot study

PURPOSE

Ocular and brain microcirculation share embryological and histological similarities. The retinal vascular fractal dimension (FD) is a marker of retinal vascular complexity of the vascular tree. The purpose of this study was to explore the relationship between cerebral blood flow (CBF), retinal vascular FD and other retinal vascular markers.

METHODS

Cross-sectional analysis comprising 26 individuals ≥65 years old from the Cognitive REServe and Clinical ENDOphenotype (CRESCENDO) cohort of relative healthy older adults. Retinal vascular FD was measured from fundus photographs by using the semi-automated Singapore Eye Vessel Assessment (SIVA) software. CBF was estimated using a 2D pulsed ASL MRI sequence. Associations between blood flow and retinal parameters were analysed using linear regression models adjusted for age and sex.

RESULTS

Cerebral blood flow was positively associated with venular FD (R²  = 0.32, p = 0.03). This association was stronger in the anterior versus posterior brain territories (R²  = 0.35 [p = 0.001] versus R²  = 0.16 [p = 0.07], respectively). Global CBF was correlated with arteriolar branching angle (R²  = 0.23, p = 0.01) and tortuosity (R²  = 0.20, p = 0.02). Global CBF was not correlated with other SIVA parameters.

CONCLUSIONS

Retinal venular complexity summarized by the FD was associated with cerebral blood flow as well as retinal arteriolar tortuosity and branching angle. Larger prospective clinical studies are needed to confirm these results.

Rehabilitation of the upper arm early after stroke: Video games versus conventional rehabilitation. A randomized controlled trial

BACKGROUND

Few rehabilitation methods have proven their efficacy in increasing sensori-motor recovery and/or function of the upper limb (UL) after stroke. Video games (VGs) are promising tools in this indication.

OBJECTIVE

To compare UL rehabilitation by using VGs and conventional rehabilitation (CR) in patients with sub-acute stroke.

DESIGN

Single-blind, multicentric trial, with central randomization and stratification by center.

SETTING

Physical and rehabilitation medicine departments of 2 university hospitals.

PARTICIPANTS

Adults within 3 months after a first vascular cerebral accident, with UL Fugl Meyer Score (UL-FMS)<30/66 and without major cognitive impairment.

INTERVENTION

A 45-min additional session of conventional occupational therapy (OT) or a VG-based OT session as add-on therapy to usual rehabilitation programs, 5 days/week for 6 weeks.

MAIN OUTCOME MEASURES

Primary outcome: UL-FMS. Secondary outcome: Box and Block Test (BBT), Wolf Motor Function test (WMFT), Motor Activity Log (MAL), Barthel Index and quality of life (SF-36).

RESULTS

We included 51 patients (20 women) at a mean (SD) of 27.2 (19.4) days post-stroke (mean age 58 years [range 24-83]), 26 in the CR group and 25 in the VG group (23 in each group at 6-month follow-up). The mean duration of the additional rehabilitation session was similar in both groups: 29.3 (4.3) vs 28.0 (4.4) min in CR and VG groups. Shoulder pain occurred in 4 patients in the VG group versus 7 in the CR group. At day 45, gain in UL-FMS did not significantly differ between the groups (CR mean 17.8 [14.6] vs VG 24.1 [14.8]; P=0.10), whereas gain in BBT was doubled in the VG group (CR 7.4 [12.2] vs VG 15.7 [16.3]; P=0.02). At 6-month follow-up, the study was inconclusive about between-group differences in UL-FMS, BBT and other criteria. Post-hoc analysis showed that gains in UL-FMS or BBT were significantly higher in the VG than CR group for patients included within 30 days post-stroke.

CONCLUSION

In general, we cannot conclude that video gaming and conventional OT led to different long-term sensorimotor recovery of the UL after sub-acute stroke. However, when applied within the first month after stroke, video gaming was more efficient than conventional rehabilitation on both sensorimotor recovery and gross grasping function.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01554449).

Alterations in Regional Homogeneity in Patients With Unilateral Chronic Tinnitus

Chronic subjective tinnitus is a widespread disorder. This perceptual anomaly is assumed to result from a dysbalance of excitatory and inhibitory mechanisms on different levels of the auditory pathways. However, the brain areas involved are still under discussion. Using resting-state functional magnetic resonance imaging, we investigate differences in cerebral regional homogeneity (ReHo) between patients with unilateral chronic tinnitus and nontinnitus control subjects. To our knowledge, our study is the first to investigate the intraregional connectivity of patients with unilateral tinnitus in relation to hearing loss. Our analyses, based on strict recruitment and characterization of the participants, showed reduced ReHo in the primary auditory cortex contralateral to the side of the perceived tinnitus percept in patients. Reduced ReHo in this same region was also correlated with increased Tinnitus Handicap Inventory and Visual Analogue Scale for loudness scores, reflecting an alteration of synchronization in this region related to the perceived loudness of the tinnitus and the related distress. Furthermore, increased ReHo in the supramarginal and angular gyri ipsilateral to the tinnitus side was correlated with increased tinnitus duration and hearing threshold at the tinnitus pitch. The correlations observed in these brain areas, which are normally related to the nontinnitus ear, could highlight compensatory mechanisms in these secondary auditory regions.

Phase Contrast MRI Suggests an Internal Carotid Vascular Tone Alteration in Migraines

INTRODUCTION

Migraine is the most common neurological disorder and the third most common disease worldwide. However, the underlying mechanisms contributing to its development are not completely understood. Symptoms may arise from a combination of dilation-independent vascular events and neurogenic mechanisms interacting throughout the brain and within the trigeminovascular system in the meninges MATERIALS AND METHOD:  We report here a case of a patient with a suspected familial hemiplegic migraine who presented an increased recurrence of events from one per month to one every other day. Three magnetic resonance imaging (MRI) acquisitions were performed after the appearance of a strong crisis which included a paresthesia and aphasia along with headaches. Two MRIs were performed close to the crisis, while the last one was done 1 month later.

RESULTS

During the crisis, cerebral perfusion exhibits incoherent results. Blood velocity measurements highlight a strong phase lag between left internal carotid artery (ICA) and basilar artery and more importantly right ICA. After a month, parameters came back to standard values.

CONCLUSION

The transitory nature of the observed modifications suggests a reversible alteration of the vascular tone of the ICA in patients with migraine. This alteration seems to follow recovery pattern of the patient.

Comparison between resting state fMRI networks and responsive cortical stimulations in glioma patients

OBJECTIVES

To validate the functional relevance of resting state networks (RSNs) by means of a comparison of resting state connectivity (RSC) between language regions elicited by direct cortical stimulation versus RSC between random regions; and to evaluate the accuracy of resting state fMRI in surgical planning by assessing the overlap between RSNs and intraoperative functional mapping results.

METHODS

Sensorimotor and language eloquent sites were identified by direct electrical cortical stimulation in 98 patients with a diffuse low-grade glioma. A seed to voxel analysis with inter-language stimulation point connectivity versus inter-random ROIs connectivity was performed (19 patients). An independant component analysis (ICA) was also applied to rsfMRI data. Language and sensorimotor components were selected over 20 independent components and compared to the corresponding stimulation points and resected cortex masks (31 and 90 patients, respectively).

RESULTS

Mean connectivity value between language seeds was significantly higher than the one between random seeds (0.68 ± 0.39 and 0.12 ± 0.21 respectively, P < 10^-10 ). 96 ± 11% of sensorimotor stimulation points were located within 10 mm from sensorimotor ICA maps versus 92 ± 21% for language. 3.1 and 15% of resected cortex overlapped sensorimotor and language networks, respectively. Mean sensorimotor stimulation points and resected cortex z-scores were 2.0 ± 1.2 and -0.050 ± 0.60, respectively (P < 10^-10 ). Mean language stimulation points and resected cortex z-scores were 1.6 ± 1.9 and 0.68 ± 0.91, respectively, P < 0.005.

CONCLUSION

The significantly higher RSC between language seeds than between random seeds validated the functional relevance of RSC. ICA partly succeeded to distinguish eloquent versus surgically removable areas and may be possibly used as a complementary tool to intraoperative mapping. Hum Brain Mapp 37:3721-3732, 2016. © 2016 Wiley Periodicals, Inc.

Assessment of Translocator Protein Density, as Marker of Neuroinflammation, in Major Depressive Disorder: A Pilot, Multicenter, Comparative, Controlled, Brain PET Study (INFLADEP Study)

Background: Major depressive disorder (MDD) is a serious public health problem with high lifetime prevalence (4.4-20%) in the general population. The monoamine hypothesis is the most widespread etiological theory of MDD. Also, recent scientific data has emphasized the importance of immuno-inflammatory pathways in the pathophysiology of MDD. The lack of data on the magnitude of brain neuroinflammation in MDD is the main limitation of this inflammatory hypothesis. Our team has previously demonstrated the relevance of [18F] DPA-714 as a neuroinflammation biomarker in humans. We formulated the following hypotheses for the current study: (i) Neuroinflammation in MDD can be measured by [18F] DPA-714; (ii) its levels are associated with clinical severity; (iii) it is accompanied by anatomical and functional alterations within the frontal-subcortical circuits; (iv) it is a marker of treatment resistance. Methods: Depressed patients will be recruited throughout 4 centers (Bordeaux, Montpellier, Tours, and Toulouse) of the French network from 13 expert centers for resistant depression. The patient population will be divided into 3 groups: (i) experimental group-patients with current MDD (n = 20), (ii) remitted depressed group-patients in remission but still being treated (n = 20); and, (iii) control group without any history of MDD (n = 20). The primary objective will be to compare PET data (i.e., distribution pattern of neuroinflammation) between the currently depressed group and the control group. Secondary objectives will be to: (i) compare neuroinflammation across groups (currently depressed group vs. remitted depressed group vs. control group); (ii) correlate neuroinflammation with clinical severity across groups; (iii) correlate neuroinflammation with MRI parameters for structural and functional integrity across groups; (iv) correlate neuroinflammation and peripheral markers of inflammation across groups. Discussion: This study will assess the effects of antidepressants on neuroinflammation as well as its role in the treatment response. It will contribute to clarify the putative relationships between neuroinflammation quantified by brain neuroimaging techniques and peripheral markers of inflammation. Lastly, it is expected to open innovative and promising therapeutic perspectives based on anti-inflammatory strategies for the management of treatment-resistant forms of MDD commonly seen in clinical practice. Clinical trial registration (reference: NCT03314155): https://www.clinicaltrials.gov/ct2/show/NCT03314155?term=neuroinflammation&cond=depression&cntry=FR&rank=1.

Time-of-flight MR angiography in cerebral venous sinus thrombosis

Recently, time-of-flight (TOF) and gadolinium-enhanced MR angiography (MRA) imaging have been used to demonstrate subacute intramural hematoma in cervical artery dissection and to detect intraplaque haemorrhage. Our aim was to perform an exploratory study to analyse if venous thrombus-related signal changes (potentially showing iso- or hyperintensity) in cerebral venous sinus thrombosis (CVST) could be observed on 3D-TOF MRA imaging. We analysed retrospectively MRIs of CVST patients in whom both contrast-enhanced MR venography (CEMRV) and 3D-TOF sequences were performed in the acute/subacute phase (i.e. < 31 days after symptom onset). The occluded sinus segments were defined on CEMRV. First, analyses of signal changes in occluded venous sinuses segments (defined by and unblinded to CEMRV) on native 3D-TOF images and morphological MRI sequences were performed. Second, a blinded (to CEMRV and other morphological MRI sequences) analysis was performed on 3D-TOF imaging assessing signal changes on 3D-TOF considering all sinus segments. Twenty-five CVST patients were included. 3D-TOF imaging showed signal changes (most often hyperintensity and less often isointensity) in 84% of the occluded sinus segments. Signal changes were observed in 91% of the occluded sinus segments on T1-weighted imaging, in 69% on T2-weighted imaging, in 68% on FLAIR, in 32% on DWI, and in 55% on T2*-weighted imaging. On blinded analysis, sensitivity of 3D-TOF sequences decreased to 80%, whereas specificity was only 65%. Abnormal signal in the venous sinuses on 3D-TOF may possibly help to suspect CVST, especially when CEMRV sequences lack.

Is impaired cerebral vasoreactivity an early marker of cognitive decline in multiple sclerosis patients?

OBJECTIVE

The link between cerebral vasoreactivity and cognitive status in multiple sclerosis remains unclear. The aim of the present study was to investigate a potential decrease of cerebral vasoreactivity in multiple sclerosis patients and correlate it with cognitive status.

METHODS

Thirty-three patients with multiple sclerosis (nine progressive and 24 remitting forms, median age: 39 years, 12 males) and 22 controls underwent MRI with a hypercapnic challenge to assess cerebral vasoreactivity and a neuropsychological assessment. Cerebral vasoreactivity, measured as the cerebral blood flow percent increase normalised by end-tidal carbon dioxide variation, was assessed globally and by regions of interest using the blood oxygen level-dependent technique. Non-parametric statistics tests were used to assess differences between groups, and associations were estimated using linear models.

RESULTS

Cerebral vasoreactivity was lower in patients with cognitive impairment than in cognitively normal patients (p=0.004) and was associated with education level in patients (R² = 0.35; p = 0.047). There was no decrease in cerebral vasoreactivity between patients and controls.

CONCLUSIONS

Cognitive impairment in multiple sclerosis may be mediated through decreased cerebral vasoreactivity. Cerebral vasoreactivity could therefore be considered as a marker of cognitive decline in multiple sclerosis.

KEY POINTS

• Cerebral vasoreactivity does not differ between multiple sclerosis patients and controls. • Cerebral vasoreactivity measure is linked to cognitive impairment in multiple sclerosis. • Cerebral vasoreactivity is linked to level of education in multiple sclerosis.

MRI volumetric morphometry in vascular parkinsonism

Vascular parkinsonism is a difficult clinical differential diagnosis in elderly subjects. We aimed at identifying morphometric markers in the brain of elderly patients with vascular parkinsonism (VP) compared with age-matched patients with Parkinson's disease (PD) and healthy controls. In this multicenter prospective study, 46 patients (80 ± 5 years old; male 32) with parkinsonism (32 PD and 14 VP) and 29 controls (mean age 78 ± 3 years; male 21) underwent brain MRI on a 3-T scanner including T1 MPRAGE and FLAIR sequences. Volumetric morphometry was obtained using Morphobox software and compared between patients and controls. Receiver operating characteristics curve analysis with computation of area under the curve (AUC) was used to compare diagnostic values. Caudate nucleus and white matter hyperintense lesions (WMHL) volumes appeared significantly higher in patients with VP. Normalized caudate volume of at least 0.67% and normalized WMHL of at least 1.11% identified patients with VP from patients with PD and controls with similar performances (p > 0.25). Caudate nucleus and WMHL volumes were positively correlated (ρ = 0.74, p < 0.0001), suggesting vascular disease related remodelling in elderly subjects. Caudate nucleus and WMHL MRI volumes might be used as additional markers to help identify patients with VP in the initial workup of elderly subjects with parkinsonian symptoms.

IDH mutation and 1p19q codeletion distinguish two radiological patterns of diffuse low-grade gliomas

Diffuse low-grade gliomas (DLGG) prognosis is variable, depending on several factors, including the isocitrate dehydrogenase (IDH) mutation and the 1p19q codeletion. A few studies suggested associations between these parameters and tumor radiological characteristics including topography. Our aim was analyzing the correlations between the IDH and 1p19q statuses and the tumor intracerebral distribution (at the lobar and voxel levels), volume, and borders. We conducted a retrospective, monocentric study on a consecutive series of 198 DLGG patients. The IDH and 1p19q statuses were recorded. The pre-treatment magnetic resonance FLAIR imagings were reviewed for determination of lobar topography, tumor volume, and characterisation of tumor borders (sharp or indistinct). We conducted a voxel-based lesion-symptom mapping analysis to investigate the correlations between the IDH and 1p19q statuses and topography at the voxel level. The IDH mutation and 1p19q statuses were correlated with the tumor topography defined using lobar anatomy (p < 0.001 and p = 0.004, respectively). Frontal tumors were more frequently IDH-mutant (87.1 vs. 57.4%) and 1p19q codeleted (45.2 vs. 17.0%) than temporo-insular lesions. At the voxel level, these associations were not found. Tumors with sharp borders were more frequently IDH-mutant (p = 0.001) while tumors with indistinct borders were more frequently IDH wild-type and 1p19q non-codeleted (p < 0.001). Larger tumors at diagnosis (possibly linked to a slower growth rate) were more frequently IDH-mutant (p < 0.001). IDH wild-type, 1p19q non-codeleted temporo-insular tumors are distinct from IDH-mutant, 1p19q codeleted frontal tumors. Further studies are needed to determine whether the therapeutic strategy should be adapted to each pattern.

The experience of social exclusion in women with a history of suicidal acts: a neuroimaging study

Suicidal behaviors result from a complex interaction between social stressors and individual vulnerability. However, little is known of the specific neural network supporting the sensitivity to social stressors in patients at risk of suicidal acts. Using functional Magnetic Resonance Imaging, we investigated brain processing of social rejection in suicide attempters. Thirty-six euthymic women with a history of depression and suicidal behavior were compared to 41 euthymic women with a history of depression but no suicidal attempt, and 28 healthy controls. The Cyberball Game was used as a validated social exclusion paradigm. Relative to healthy controls, both patient groups reported higher levels of social distress related to the task, without significant differences according to suicidal status. Compared to patients without any history of suicide attempt and healthy controls, suicide attempters showed decreased contrast in the left insula and supramarginal gyrus during the exclusion vs. inclusion condition, after controlling for number of depressive episodes, medication, mood disorder type or social phobia. Our study highlights impaired brain response to social exclusion in euthymic female suicide attempters in regions previously implicated in pain tolerance and social cognition. These findings suggest sustained brain dysfunctions related to social perception in suicide attempters.

Subcortical nuclei volumes in suicidal behavior: nucleus accumbens may modulate the lethality of acts

Previously, studies have demonstrated cortical impairments in those who complete or attempt suicide. Subcortical nuclei have less often been implicated in the suicidal vulnerability. In the present study, we investigated, with a specific design in a large population, variations in the volume of subcortical structures in patients with mood disorders who have attempted suicide. We recruited 253 participants: 73 suicide attempters with a past history of both mood disorders and suicidal act, 89 patient controls with a past history of mood disorders but no history of suicidal act, and 91 healthy controls. We collected 1.5 T magnetic resonance imaging data from the caudate, pallidum, putamen, nucleus accumbens, hippocampus, amygdala, ventral diencephalon, and thalamus. Surface-based morphometry (Freesurfer) analysis was used to comprehensively evaluate gray matter volumes. In comparison to controls, suicide attempters showed no difference in subcortical volumes when controlled for intracranial volume. However, within attempters negative correlations between the left (r = -0.35, p = 0.002), and right (r = -0.41, p < 0.0005) nucleus accumbens volumes and the lethality of the last suicidal act were found. Our study found no differences in the volume of eight subcortical nuclei between suicide attempters and controls, suggesting a lack of association between these regions and suicidal behavior in general. However, individual variations in nucleus accumbens structure and functioning may modulate the lethality of suicidal acts during a suicidal crisis. The known role of nucleus accumbens in action selection toward goals determined by the prefrontal cortex, decision-making or mental pain processing are hypothesized to be potential explanations.

Corpus callosum integrity is affected by mood disorders and also by the suicide attempt history: A diffusion tensor imaging study

BACKGROUND

Some MRI studies have noted alterations in the corpus callosum (CC) white matter integrity of individuals with mood disorders and also in patients with suicidal behavior. We investigated the specific impact of suicidal behavior on CC integrity in mood disorders.

METHODS

CC structural changes were assessed by diffusion tensor imaging (DTI) in 121 women 18-50-year-old): 41 with bipolar disorder (BD), 50 with major depressive disorder (MDD) and 30 healthy controls (HC). Fractional anisotropy (FA) and DTI metrics were calculated for the genu, body and splenium of CC and compared in the three groups by MANCOVA. Then, they were re-analyzed relative to the suicide attempt history within the MDD and BD groups and to the suicide number/severity.

RESULTS

FA values for the CC genu and body were lower in non-suicide attempters with BD than with MDD and in HC. Conversely, FA values for all CC regions were significantly lower in suicide attempters with BD than in HC. Finally, higher number of suicide attempts (>2) and elevated Suicidal Intent Scale score were associated with significant splenium alterations.

LIMITATIONS

Limitations include the cross-sectional design (non-causal study), the potential influence of medications and concerns about the generalizability to men.

CONCLUSION

Genu and body are altered in non-suicide attempters with BD, while splenium is specifically altered in suicide attempters, independently from their psychiatric status. History of suicide attempts may be a source of heterogeneity in the association between CC alterations and BD and may partially explain the variable results of previous studies.

Recovery of functional connectivity of the sensorimotor network after surgery for diffuse low-grade gliomas involving the supplementary motor area

OBJECTIVE The supplementary motor area (SMA) syndrome is a well-studied lesional model of brain plasticity involving the sensorimotor network. Patients with diffuse low-grade gliomas in the SMA may exhibit this syndrome after resective surgery. They experience a temporary loss of motor function, which completely resolves within 3 months. The authors used functional MRI (fMRI) resting state analysis of the sensorimotor network to investigate large-scale brain plasticity between the immediate postoperative period and 3 months' follow-up. METHODS Resting state fMRI was performed preoperatively, during the immediate postoperative period, and 3 months postoperatively in 6 patients with diffuse low-grade gliomas who underwent partial surgical excision of the SMA. Correlation analysis within the sensorimotor network was carried out on those 3 time points to study modifications of its functional connectivity. RESULTS The results showed a large-scale reorganization of the sensorimotor network. Interhemispheric connectivity was decreased in the postoperative period, and increased again during the recovery process. Connectivity between the lesion side motor area and the contralateral SMA rose to higher values than in the preoperative period. Intrahemispheric connectivity was decreased during the immediate postoperative period and had returned to preoperative values at 3 months after surgery. CONCLUSIONS These results confirm the findings reported in the existing literature on the plasticity of the SMA, showing large-scale modifications of the sensorimotor network, at both inter- and intrahemispheric levels. They suggest that interhemispheric connectivity might be a correlate of SMA syndrome recovery.

Working memory performance is related to intrinsic resting state functional connectivity changes in community-dwelling elderly cohort

Characterization of normal age-related changes in resting state brain networks associated with working memory performance is a major prerequisite for studying neurodegenerative diseases. The aim of this study was to investigate the relationship between performing a working memory task (under MRI) and resting-state brain networks in a large cohort of healthy elderly subjects (n=337). Functional connectivity and interactions between networks were assessed within the default mode (DMN), salience (SN), and right and left central executive (CEN) networks in two groups of subjects classed by their performance (low and high). The low performance group showed lower functional connectivity in both the DMN and SN, and higher functional connectivity in the right and left CEN compared to the high performance group. Overall the functional connectivity within the DMN and the CEN were correlated. The lower functional connectivity within the DMN and SN in the low performance group is suggestive of altered attentional and memory processes and/or altered motivation. The higher functional connectivity within the CEN could be related to compensatory mechanisms, without which the subjects would have even lower performances. The correlation between the DMN and CEN suggests a modulation between the lower functional connectivity within the DMN and the higher functional connectivity within the CEN when performance is reduced. Finally, this study suggests that performance modifications in healthy elderly subjects are associated with reorganization of functional connectivity within the DMN, SN, and CEN.

MR derived volumetric flow rate waveforms of internal carotid artery in patients treated for unruptured intracranial aneurysms by flow diversion technique

Little is known about the hemodynamic disturbances induced by the cerebral aneurysms in the parent artery and the effect of flow diverter stents (FDS) on these latter. A better understanding of the aneurysm-parent vessel complex relationship may aid our understanding of this disease and to optimize its treatment. The ability of volumetric flow rate (VFR) waveform to reflect the arterial compliance modifications is well known. By analyzing the VFR waveform and the pulsatility in the parent vessel, this study aimed to test the hypotheses that (1) intracranial aneurysms might disrupt the blood flow of the parent vessel and (2) the treatment by FDS might have measurable corrective effect on these changes. Ten patients followed for unruptured intracranial aneurysms treated by FDS and ten healthy volunteers as control group were included in this study. Two-dimensional quantitative phase-contrast magnetic resonance imaging (MRI) was performed on each patient on the ICA artery upstream and downstream to the aneurysm, and on each volunteer at similar locations. The aneurysms altered significantly the parent vessel pulsatility and this effect was correlated to their volume. The aneurysms treatment by FDS allowed for the restoration of a normally modulated flow and pulsatility correction in the parent vessel.

Neuroradiological findings expand the phenotype of OPA1-related mitochondrial dysfunction

OBJECTIVE

OPA1 mutations are responsible for more than half of autosomal dominant optic atrophy (ADOA), a blinding disease affecting the retinal ganglion neurons. In most patients the clinical presentation is restricted to the optic nerve degeneration, albeit in 20% of them, additional neuro-sensorial symptoms might be associated to the loss of vision, as frequently encountered in mitochondrial diseases. This study describes clinical and neuroradiological features of OPA1 patients.

METHODS

Twenty two patients from 17 families with decreased visual acuity related to optic atrophy and carrying an OPA1 mutation were enrolled. Patients underwent neuro-ophthalmological examinations. Brain magnetic resonance imaging (T1, T2 and flair sequences) was performed on a 1.5-Tesla MR Unit. Twenty patients underwent 2-D proton spectroscopic imaging.

RESULTS

Brain imaging disclosed abnormalities in 12 patients. Cerebellar atrophy mainly involving the vermis was observed in almost a quarter of the patients; other abnormalities included unspecific white matter hypersignal, hemispheric cortical atrophy, and lactate peak. Neurological examination disclosed one patient with a transient right hand motor deficit and ENT examination revealed hearing impairment in 6 patients. Patients with abnormal MRI were characterized by: (i) an older age (ii) more severe visual impairment with chronic visual acuity deterioration, and (iii) more frequent associated deafness.

CONCLUSIONS

Our results demonstrate that brain imaging abnormalities are common in OPA1 patients, even in those with normal neurological examination. Lactate peak, cerebellar and cortical atrophies are consistent with the mitochondrial dysfunction related to OPA1 mutations and might result from widespread neuronal degeneration.

Corpus callosum size may predict late-life depression in women: a 10-year follow-up study

BACKGROUND

Recent research on late-life depression (LLD) pathophysiology suggests the implication of abnormalities in cerebral white matter and particularly in interhemispheric transfer. Corpus callosum (CC) is the main brain interhemispheric commissure. Hence, we investigated the association between baseline CC measures and risk of LDD.

METHODS

We studied 467 non-demented individuals without LLD at baseline from a cohort of elderly community-dwelling people (the ESPRIT study). LLD was assessed at year 2, 4, 7 and 10 of the study follow-up. At baseline, T1-weighted magnetic resonance images were manually traced to measure the mid-sagittal areas of the anterior, mid and posterior CC. Multivariate Cox proportional hazards models stratified by sex were used to predict LLD incidence over 10 years.

RESULTS

A significant interaction between gender and CC size was found (p=0.02). LLD incidence in elderly women, but not in men, was significantly associated with smaller anterior (HR 1.37 [1.05-1.79] p=0.017), mid (HR 1.43 [1.09-1.86] p=0.008), posterior (HR 1.39 [1.12-1.74] p=0.002) and total (HR 1.53 [1.16-2.00] p=0.002) CC areas at baseline in Cox models adjusted for age, education, global cognitive impairment, ischemic pathologies, left-handedness, white matter lesion, intracranial volume and past depression.

LIMITATIONS

The main limitation was the retrospective assessment of major depression.

CONCLUSION

Smaller CC size is a predictive factor of incident LLD over 10 years in elderly women independently of cognitive deterioration. Our finding suggests a possible role of CC and reduced interhemispheric connectivity in LLD pathophysiology. Extensive explorations are needed to clarify the mechanisms leading to CC morphometric changes in mood disorders.

Diffusion tensor imaging differentiates vascular parkinsonism from parkinsonian syndromes of degenerative origin in elderly subjects

BACKGROUND AND PURPOSE

The etiologic diagnosis of parkinsonian syndromes is of particular importance when considering syndromes of vascular or degenerative origin. The purpose of this study is to find differences in the white-matter architecture between those two groups in elderly patients.

MATERIALS AND METHODS

Thirty-five patients were prospectively included (multiple-system atrophy, n=5; Parkinson's disease, n=15; progressive supranuclear palsy, n=9; vascular parkinsonism, n=6), with a mean age of 76 years. Patients with multiple-system atrophy, progressive supranuclear palsy and Parkinson's disease were grouped as having parkinsonian syndromes of degenerative origin. Brain MRIs included diffusion tensor imaging. Fractional anisotropy and mean-diffusivity maps were spatially normalized, and group analyses between parkinsonian syndromes of degenerative origin and vascular parkinsonism were performed using a voxel-based approach.

RESULTS

Statistical parametric-mapping analysis of diffusion tensor imaging data showed decreased fractional anisotropy value in internal capsules bilaterally in patients with vascular parkinsonism compared to parkinsonian syndromes of degenerative origin (p=0.001) and showed a lower mean diffusivity in the white matter of the left superior parietal lobule (p=0.01). Fractional anisotropy values were found decreased in the middle cerebellar peduncles in multiple-system atrophy compared to Parkinson's disease and progressive supranuclear palsy. The mean diffusivity was increased in those regions for these subgroups.

CONCLUSION

Clinically defined vascular parkinsonism was associated with decreased fractional anisotropy in the deep white matter (internal capsules) compared to parkinsonian syndromes of degenerative origin. These findings are consistent with previously published neuropathological data.

Depression in elderly persons subject to childhood maltreatment is not modulated by corpus callosum and hippocampal loss

Childhood adversity has been observed to engender structural changes in the hippocampus and corpus callosum associated with increased risk for depression in childhood and early adulthood. This study investigated this association in the elderly. Corpus callosum area and hippocampal volume were measured from structural MRI in 427 community dwelling elderly. Information on childhood adversity was obtained in the course of a clinical examination using a questionnaire covering multiple aspects of abuse. Multivariate analyses found a significant increase in corpus callosum area and hippocampal volume in subjects exposed to mental disorder in parents and poverty, respectively. No association was found with childhood sexual and physical abuse.

Middle longitudinal fasciculus delineation within language pathways: a diffusion tensor imaging study in human

INTRODUCTION

The existence in the human brain of the middle longitudinal fasciculus (MdLF), initially described in the macaque monkey, is supported by diffusion tensor imaging studies. In the present work, we aim (1) to confirm that this fascicle is found constantly in control subjects with the use of DTI techniques and (2) to delineate the MdLF from the other fiber bundles that constitute the language pathways.

MATERIALS AND METHODS

Tractography was realized in four right-handed healthy volunteers for the arcuate fascicle, uncinate fascicle, inferior fronto-occipital fascicle, inferior longitudinal fascicle and the middle longitudinal fascicle. The fiber tracts were characterized for their size, mean fractional anisotropy (FA), for their length, number of streamlines, and lateralization indices were calculated.

RESULTS

The MdLF is found constantly and it is clearly delineated from the other fascicles that constitute the language pathways, especially the ventral pathway. It runs within the superior temporal gyrus white matter from the temporal pole, then it extends caudally in the upper part of the sagittal stratum and the posterior part of the corona radiata, to reach the inferior parietal lobule (angular gyrus). We found a leftward asymmetry for all fiber tracts when considering the mean FA.

DISCUSSION

Using DTI methods, we confirm that the MdLF connects the angular gyrus and the superior temporal gyrus. On the basis of these findings, the role of the MdLF is discussed.

CONCLUSION

The middle longitudinal fasciculus, connects the angular gyrus and the superior temporal gyrus and its course can be systematically differenciated from those of other fascicles composing both ventral and dorsal routes (IFOF, IFL, AF and UF).