Neurometabolite correlates with personality and stress in healthy emerging adults: A focus on sex differences.

Personality traits have been linked with both brain structure and function. However, the exact relationship between personality traits and other behavioural measures with neurometabolites, measured with proton magnetic resonance spectroscopy, is not clear. Here we investigated the association between behavioural measures (i.e., personality traits, resilience, perceived stress, self-esteem, hopelessness, psychological distress) and metabolite ratios (i.e., of choline-containing compounds [Cho], creatine and phosphocreatine [Cr], and N-acetyl-aspartate [NAA]) in the posterior cingulate cortex (pCC) and the dorsal anterior cingulate cortex (dACC) and surrounding white matter (WM) regions in healthy emerging adults (N = 57, 26 women, mean age=23.40 years, SD=2.50). The pCC and the dACC were selected for their known involvement as important brain network hubs and their association to five factor personality dimensions and other psychological measures. Spectral analysis as well as statistics for demographic, clinical, and imaging data were performed. Correlation and multiple regression analyses were used to test the relationship between metabolite ratios and behavioural scores in the entire sample as well as in female and male participants separately. The entire sample showed significant (p<0.05) negative correlates of stress with the NAA/Cr ratio in the pCC, and of extraversion with WM metabolite ratios. In regards of sex differences, a significantly higher NAA/Cho ratio in the pCC (p<0.05), the dACC (p<0.01), and in the left and right posterior WM matter (p<0.05), and a lower Cho/Cr ratio in the dACC (p<0.01) was detected in women. Moreover, the two sexes differed in regards of metabolite correlates of openness, conscientiousness, extraversion, agreeableness, neuroticism, stress, hopelessness, and self-esteem, and in multiple regression model predictions. Our results point to a role of the ACC in conscientiousness through its involvement in higher-order cognitive control as part of the salience network and internally directed thoughts as part of the default mode network (DMN). Furthermore, the two sexes differ in terms of metabolite correlates of openness and conscientiousness in the pCC, suggesting mental process involvement through the DMN, and of agreeableness in the dACC, possibly through involvement in social cognitive processes, particularly in women. Additionally, our results suggest that the ACC is linked to the so-called Alpha-factor of personality. Our findings on stress correlates contribute to the existing literature of the involvement of the ACC as part of the limbic system. In addition, our results suggest a possible role of the pCC in stress-regulatory processes through a possible co-involvement of stress, hopelessness, and self-esteem in the pCC in men, where higher self-esteem may help to cope with stress.

Attachment status is associated with grey matter recovery in adolescent anorexia nervosa: Findings from a longitudinal study.

The aim of the present study was to investigate whether grey matter (GM) reductions in acute anorexia nervosa (AN) are (i) valid for adolescents (age 14-18 years), (ii) reversible following short-term psychotherapeutic and nutritional therapy and (iii) depend on psychological components like attachment trauma. 3T MRI including a high-resolution T1 MPRAGE was performed in 22 female adolescents in the acute state of AN (age: 15.2 ± 1.2 years) and after weight restoration (duration: 2.6 ± 1 months, n = 18) and compared with 18 gender-matched healthy controls. The Adult Attachment Projective Picture System was used to classify resolved and unresolved attachment patterns. GM decreases were localized in extensive cortical areas including the insula, prefrontal and cingulate cortices as well as subcortical regions during acute AN, which partially increased after therapy with a relative sparing of the hippocampus and parahippocampal gyrus. The resolved group showed more GM recovery in regions of the left hippocampus and parahippocampal gyrus, bilateral cerebellar regions, right precuneus and adjacent cingulate cortices relative to the unresolved pattern. Structural anomalies in adolescent AN that recovered after treatment may be primarily the consequence of malnutrition, whereas several regions did not display significant recovery. Attachment status seems to influence region-specific GM recovery.

Energy metabolism measured by 31P magnetic resonance spectroscopy in the healthy human brain.

BACKGROUND AND PURPOSE: Phosphorous magnetic resonance spectroscopy (31P-MRS) allows a non-invasive analysis of phosphorus-containing compounds in vivo. The present study investigated the influence of brain region, hemisphere, age, sex and brain volume on 31P-MRS metabolites in healthy adults. MATERIALS AND METHODS: Supratentorial brain 31P-MRS spectra of 125 prospectively recruited healthy volunteers (64 female, 61 male) aged 20 to 85 years (mean: 49.4 ± 16.9 years) were examined with a 3D-31P-MRS sequence at 3T, and the compounds phosphocreatine (PCr), inorganic phosphate (Pi) and adenosine triphosphate (ATP) were measured. From this data, the metabolite ratios PCr/ATP, Pi/ATP and PCr/Pi were calculated for different brain regions. In addition, volumes of gray matter, white matter and cerebrospinal fluid were determined. RESULTS: For all metabolite ratios significant regional differences and in several regions sex differences were found. In some brain regions and for some metabolites hemispheric differences were detected. In addition, changes with aging were found, which differed between women and men. CONCLUSIONS: The present results indicate that 31P-MRS metabolism varies throughout the brain, with age and between sexes, and therefore have important practical implications for the design and the interpretation of future 31P-MRS studies under physiological conditions and in patients with various cerebral diseases.

Familial writer's cramp: a clinical clue for inherited coenzyme Q10 deficiency.

The spectrum of coenzyme Q10 (CoQ10) deficiency syndromes comprises a variety of disorders, including a form of autosomal recessive cerebellar ataxia (ARCA2) caused by mutations in the AarF domain-containing kinase 3 gene (ADCK3). Due to the potential response to CoQ10 supplementation, a timely diagnosis is crucial. Herein, we describe two siblings with a novel homozygous ADCK3 variant and an unusual presentation consisting of isolated writer's cramp with adult-onset. Cerebellar ataxia developed later in the disease course and remained stable during the follow-up. This report highlights that ARCA2 should be considered in the differential diagnosis of familial writer's cramp.

Dual-energy computed tomography in acute ischemic stroke: state-of-the-art.

Dual-energy computed tomography (DECT) allows distinguishing between tissues with similar X-ray attenuation but different atomic numbers. Recent studies demonstrated that this technique has several areas of application in patients with ischemic stroke and a potential impact on patient management. After endovascular stroke therapy (EST), hyperdense areas can represent either hemorrhage or contrast staining due to blood-brain barrier disruption, which can be differentiated reliably by DECT. Further applications are improved visualization of early infarctions, compared to single-energy computed tomography, and prediction of transformation into infarction or hemorrhage in contrast-enhancing areas. In addition, DECT allows detection and evaluation of the material composition of intra-arterial clots after EST. This review summarizes the clinical state-of-the-art of DECT in patients with stroke, and features some prospects for future developments. KEY POINTS: • Dual-energy computed tomography (DECT) allows differentiation between tissues with similar X-ray attenuation but differentatomic numbers. • DECT has several areas of application in patients with ischemic stroke and a potential impact on patient management. • Prospects for future developments in DECT may improve treatment decision-making.

Cerebral Energy Status and Altered Metabolism in Early Severe TBI: First Results of a Prospective 31P-MRS Feasibility Study.

OBJECTIVE: Severe traumatic brain injury (sTBI) represents a serious public health issue with high morbidity and mortality. Neuroimaging plays a crucial role in the evaluation of sTBI patients. Phosphorous magnetic resonance spectroscopy (31P-MRS) is an imaging technique for evaluation of energy metabolites. The aim of this study is to evaluate the feasibility and the diagnostic potential of ultra-early 31P-MRS to detect changes in cerebral energy metabolism in sTBI. METHODS: Adult patients with sTBI presenting with GCS ≤ 8 being eligible for MRI were prospectively included in the study and MRI was performed within 72 h after trauma. Imaging was performed using a 3 Tesla MRI. 31P-MRS data from the structurally affected side were compared to data from normal appearing contralateral areas symmetrically to the location of the traumatic lesions, and to data of matched healthy controls. RESULTS: Ten sTBI patients (3 female, 7 male), aged between 20 and 75 years, with a mean initial GCS of 6 were analyzed. MRI was performed 61 h (mean, range 37-71 h) after trauma. Statistical analysis revealed no significant differences between the lesioned side and contralaterally. An increased PCr/ATP ratio and a decreased PME/PDE ratio were present in structurally normal appearing, but traumatized tissue when compared to the healthy population, thus indicating significant differences in ATP resynthesis and membrane turnover (F (2,33), P = 0.005 and, P = 0.027, respectively). CONCLUSION: 31P-MRS could provide a better understanding of pertinent global changes in cerebral energy metabolism in sTBI patients under general anesthesia.

Impairment of odor discrimination and identification is associated with disability progression and gray matter atrophy of the olfactory system in MS.

BACKGROUND: Impairment of odor discrimination (D), identification (I), and threshold (T) are characteristic features of multiple sclerosis (MS). OBJECTIVE: To identify patterns of gray matter concentration (GMC) associated with different qualities of olfactory function. METHODS: Olfactory function (T and combined DI score) was measured by Sniffin' Sticks-Test over 2 years longitudinally, and T1-weighted 3-T magnetic resonance imaging (MRI) was performed in 37 MS patients and 18 matched healthy controls (HCs). Statistical parametric mapping (SPM) was applied to objectively identify changes of voxel-wise-GMC throughout the entire brain volume and to correlate image parameters with odor function. RESULTS: SPM localized significant GMC decreases in the anterior cingulum as well as temporomesial and frontobasal brain areas of the MS group compared with HCs, and revealed significant correlations between lower DI scores and GMC decreases in the olfactory gyrus, anterior cingulum, temporal regions including the parahippocampus, and putamen. Contrarily, no correlations were found between T and GMC. Patients with disability progression had significantly lower mean temporomesial/putamen GMC (0.782 vs 0.804, p = 0.004) compared to patients without Expanded Disability Status Scale (EDSS) progression. CONCLUSION: Impairment of DI, but not T is associated with GM atrophy in brain regions related to olfactory function. Further studies are warranted to investigate DI scores and temporomesial/putamen GMC as biomarkers for disability progression.

Effects of Cognitive Functioning and Education on Later-Life Health Numeracy.

INTRODUCTION: Previous studies have shown an association between a high health numeracy and good cognitive functioning. OBJECTIVE: To investigate the moderation effect of education on this relationship and which brain structures support health numeracy. METHODS: We examined 70 healthy older persons (66% females; mean ± SD: age, 75.73 ± 4.52 years; education, 12.21 ± 2.94 years). The participants underwent a T1-weighted 3-T MRI and a neuropsychological assessment including a health numeracy task. Statistical parametric mapping was applied to identify focal changes in cortical thickness throughout the entire brain and to correlate image parameters with behavioral measures. RESULTS: Executive functions and mental calculation emerged as predictors of health numeracy (B = 0.22, p < 0.05, and B = 0.38, p < 0.01). An interaction was found between education and executive functions (B = -0.16, p = 0.01) and between education and mental calculation (B = -0.11, p < 0.05). Executive functions and mental calculation had an impact on health numeracy in participants with a low to intermediate edu-cation (≤12 years) but not in those with a higher education (>12 years). Health numeracy scores were associated with cortical thickness in the right dorsomedial prefrontal cortex and the right superior temporal gyrus (p = 0.01). CONCLUSIONS: Older people with a higher education perform better in health numeracy tasks than those with a lower education. They have access to previously acquired knowledge about ratio concepts and do not need to rely on executive functions and computational skills. This is highly relevant when decisions about health care have to be made.

Mapping the human brainstem: Brain nuclei and fiber tracts at 3 T and 7 T.

Structural high-resolution imaging of the brainstem can be of high importance in clinical practice. However, ultra-high field magnetic resonance imaging (MRI) is still restricted in use due to limited availability. Therefore, quantitative MRI techniques (quantitative susceptibility mapping [QSM], relaxation measurements [ R2* , R1 ], diffusion tensor imaging [DTI]) and T2 - and proton density (PD)-weighted imaging in the human brainstem at 3 T and 7 T are compared. Five healthy volunteers (mean age: 21.5 ± 1.9 years) were measured at 3 T and 7 T using multi-echo gradient echo sequences for susceptibility mapping and R2* relaxometry, magnetization-prepared 2 rapid acquisition gradient echo sequences for R1 relaxometry, turbo-spin echo sequences for PD- and T2 -weighted imaging and readout-segmented echo planar sequences for DTI. Susceptibility maps were computed using Laplacian-based phase unwrapping, V-SHARP for background field removal and the streaking artifact reduction for QSM algorithm for dipole inversion. Contrast-to-noise ratios (CNRs) were determined at 3 T and 7 T in ten volumes of interest (VOIs). Data acquired at 7 T showed higher CNR. However, in four VOIs, lower CNR was observed for R2* at 7 T. QSM was shown to be the contrast with which the highest number of structures could be identified. The depiction of very fine tracts such as the medial longitudinal fasciculus throughout the brainstem was only possible in susceptibility maps acquired at 7 T. DTI effectively showed the main tracts (crus cerebri, transverse pontine fibers, corticospinal tract, middle and superior cerebellar peduncle, pontocerebellar tract, and pyramid) at both field strengths. Assessing the brainstem with quantitative MRI methods such as QSM, R2* , as well as PD- and T2 -weighted imaging with great detail, is also possible at 3 T, especially when using susceptibility mapping calculated from a gradient echo sequence with a wide range of echo times from 10.5 to 52.5 ms. However, tracing smallest structures strongly benefits from imaging at ultra-high field.

Morphometric MRI profiles of multiple system atrophy variants and implications for differential diagnosis.

BACKGROUND: Manual width measurements of the middle cerebellar peduncle on MRI were shown to improve the accuracy of an imaging-guided diagnosis of multiple system atrophy (MSA). Recently, automated volume segmentation algorithms were able to reliably differentiate patients with Parkinson's disease (PD) and the parkinsonian variant of MSA. The objective of the current study was to integrate probabilistic information of the middle cerebellar peduncle into an existing MRI atlas for automated subcortical segmentation and to evaluate the diagnostic properties of the novel atlas for the differential diagnosis of MSA (parkinsonian and cerebellar variant) versus PD. METHODS: Three Tesla MRI scans of 48 healthy individuals were used to establish an automated whole-brain segmentation procedure that includes the volumes of the putamen, cerebellar gray and white matter, and the middle cerebellar peduncles. Classification accuracy of segmented volumes were tested in early-stage MSA patients (18 MSA-parkinsonism, 13 MSA-cerebellar) and 19 PD patients using a C4.5 classifier. RESULTS: Putaminal and infratentorial atrophy were present in 77.8% and 61.1% of MSA-parkinsonian patients, respectively. Four of 18 MSA-parkinsonian patients (22.2%) had infratentorial atrophy without evidence of putaminal atrophy. Infratentorial atrophy was present in all MSA-cerebellar patients, with concomitant putaminal atrophy in 46.2% of these cases. The diagnostic algorithm using putaminal and infratentorial volumetric information correctly classified all PD patients and 96.8% of MSA patients. CONCLUSIONS: The middle cerebellar peduncle was successfully integrated into a subcortical segmentation atlas, and its excellent diagnostic accuracy outperformed existing volumetric MRI processing strategies in differentiating MSA patients with variable atrophy patterns from PD patients. © 2019 International Parkinson and Movement Disorder Society.

Improved visualisation of early cerebral infarctions after endovascular stroke therapy using dual-energy computed tomography oedema maps.

OBJECTIVE: The aim was to investigate whether dual-energy computed tomography (DECT) reconstructions optimised for oedema visualisation (oedema map; EM) facilitate an improved detection of early infarctions after endovascular stroke therapy (EST). METHODS: Forty-six patients (21 women; 25 men; mean age: 63 years; range 24-89 years) were included. The brain window (BW), virtual non-contrast (VNC) and modified VNC series based on a three-material decomposition technique optimised for oedema visualisation (EM) were evaluated. Follow-up imaging was used as the standard for comparison. Contralateral side to infarction differences in density (CIDs) were determined. Infarction detectability was assessed by two blinded readers, as well as image noise and contrast using Likert scales. ROC analyses were performed and the respective Youden indices calculated for cut-off analysis. RESULTS: The highest CIDs were found in the EM series (73.3 ± 49.3 HU), compared with the BW (-1.72 ± 13.29 HU) and the VNC (8.30 ± 4.74 HU) series. The EM was found to have the highest infarction detection rates (area under the curve: 0.97 vs. 0.54 and 0.90, p < 0.01) with a cut-off value of < 50.7 HU, despite slightly more pronounced image noise. The location of the infarction did not affect detectability (p > 0.05 each). CONCLUSIONS: The EM series allows higher contrast and better early infarction detection than the VNC or BW series after EST. KEY POINTS: • Dual-energy CT EM allows better early infarction detection than standard brain window. • Dual-energy CT EM series allow better early infarction detection than VNC series. • Dual-energy CT EM are modified VNC based on water content of tissue.

Cervical artery tortuosity-a reliable semi-automated magnetic resonance-based method.

Background: Assessments of subclinical connective tissue disorders depend on complex approaches, emphasizing the need for more accessible methods applicable to clinical routine. Therefore, we aimed to establish a reliable approach assessing cervical vessel tortuosity, which is known to be associated with such disorders. Methods: Magnetic resonance angiography (MRA) images of ReSect study participants [single-center prospective cohort of spontaneous cervical artery dissection (sCeAD) patients] were used. Each patient underwent the same magnetic resonance imaging (MRI) protocol. The segmentation procedure was done using MATrix LABoratory 9.4 [up-sampling of raw MRA images, distance metric (DM) calculation], ITK-SNAP [region of interest (ROI) determination, vessel segmentation] and Vascular Modelling ToolKit (centerline determination). To assess inter-user variability and validity, we (I) had two blinded independent users segment all arteries and we (II) compared the results of our method to visual appraisal of vessel tortuosity done by two blinded expert neuro-radiologists. Results: A total of 526 extracranial cervical arteries were available for analysis. The inter-user variability of our method users was below 0.5% throughout. Overall, our method outperformed the visual tortuosity appraisal, as the visual grading underestimated the DM in 38.8% subjects when tasked to assess overall cervical artery tortuosity (both vertebral and internal carotid arteries) and in 16.6% and 33.3% respectively if tasked to grade anterior or posterior circulation separately. Conclusions: We present a reliable method to assess cervical artery tortuosity derived from MRA images applicable in clinical routine and future research investigating the potential correlation of sCeAD and connective tissue disorder.

Could Phosphorous MR Spectroscopy Help Predict the Severity of Vasospasm? A Pilot Study.

One of the main causes of the dismal prognosis in patients who survive the initial bleeding after aneurysmal subarachnoidal hemorrhage is the delayed cerebral ischaemia caused by vasospasm. Studies suggest that cerebral magnesium and pH may potentially play a role in the pathophysiology of this adverse event. Using phosphorous magnetic resonance spectrocopy (31P-MRS), we calculated the cerebral magnesium (Mg) and pH levels in 13 patients who suffered from aSAH. The values between the group that developed clinically significant vasospasm (n = 7) and the group that did not (n = 6) were compared. The results of this study show significantly lower cerebral Mg levels (p = 0.019) and higher pH levels (p < 0.001) in the cumulative group (all brain voxels together) in patients who developed clinically significant vasospasm. Further clinical studies on a larger group of carefully selected patients are needed in order to predict clinically significant vasospasm.

Mapping of phase singularities with spiral phase contrast microscopy.

In spiral phase contrast (SPC) microscopy the edge-enhancement is typically independent of the helicity of the phase vortex filter. Here we show that for layered specimens containing screw-dislocations, as are e.g. present in mica or some crystallized organic substances, the intensity distribution in the filtered image acquires a dependence on the rotational direction of the filter. This allows one to map the distribution of phase singularities in the topography of the sample, by taking the intensity difference between two images recorded with opposite handedness. For the demonstration of this feature in a microscopy set-up, we encode the vortex filter as a binary off-axis hologram displayed on a spatial light modulator (SLM) placed in a Fourier plane. Using a binary grating, the diffraction efficiencies for the plus and minus first diffraction orders are equal, giving rise to two image waves which travel in different directions and are Fourier filtered with opposite helicity. The corresponding two images can be recorded simultaneously in two separate regions of the camera chip. This enables mapping of dislocations in the sample in a single camera exposure, as was demonstrated for various transparent samples.

Evaluation of visual food stimuli paradigms on healthy adolescents for future use in fMRI studies in anorexia nervosa.

BACKGROUND: Mostly, visual food stimuli paradigms for functional Magnetic Resonance Imaging are used in studies of eating disorders. However, the optimal contrasts and presentation modes are still under discussion. Therefore, we aimed to create and analyse a visual stimulation paradigm with defined contrast. METHODS: In this prospective study, a block-design fMRI paradigm with conditions of randomly altering blocks of high- and low-calorie food images and images of fixation cross was established. Food pictures were rated in advance by a group of patients diagnosed with anorexia nervosa to address the dedicated perception of patients with eating disorders. To optimize the scanning procedure and fMRI contrasts we have analysed neural activity differences between high-calorie stimuli versus baseline (H vs. X), low-calorie stimuli versus baseline (L vs. X) and high- versus low-calorie stimuli (H vs. L). RESULTS: By employing the developed paradigm, we were able to obtain results comparable to other studies and analysed them with different contrasts. Implementation of the contrast H versus X led to increased blood-oxygen-level-dependent signal (BOLD) mainly in unspecific areas, such as the visual cortex, the Broca´s area, bilaterally in the premotor cortex and the supplementary motor area, but also in thalami, insulae, the right dorsolateral prefrontal cortex, the left amygdala, the left putamen (p < .05). When applying the contrast L versus X, an enhancement of the BOLD signal was detected similarly within the visual area, the right temporal pole, the right precentral gyrus, Broca´s area, left insula, left hippocampus, the left parahippocampal gyrus, bilaterally premotor cortex and thalami (p < .05). Comparison of brain reactions regarding visual stimuli (high- versus low-calorie food), assumed to be more relevant in eating disorders, resulted in bilateral enhancement of the BOLD signal in primary, secondary and associative visual cortex (including fusiform gyri), as well as angular gyri (p < .05). CONCLUSIONS: A carefully designed paradigm, based on the subject's characteristics, can increase the reliability of the fMRI study, and may reveal specific brain activations elicited by this custom-built stimuli. However, a putative disadvantage of implementing the contrast of high- versus low-calorie stimuli might be the omission of some interesting outcomes due to lower statistical power. Trial registration NCT02980120.

Although the relationship with food is crucial for living, its underlying mechanisms (e.g., neurological, cognitive, physiological) are still not fully discovered. The development of functional magnetic resonance imaging made it possible to explore brain's responses to images of food. However, a proper methodological analysis of the research paradigm is still lacking. Here, we present the optimization of visual food stimuli paradigms achieved by comparison of neural activations of 20 female healthy adolescents after applying particular contrasts (i.e., high- versus low-calorie food images, high-calorie food images versus baseline, low-calorie food images versus baseline). Application of the contrast high- versus low-calorie food images resulted in stronger neural activation in visual cortex (including fusiform gyri) and angular gyri. This study highlights the importance of choosing a proper contrast regarding the study hypothesis, as it may induce more specific results. However, it may lead to loss of some outcomes, due to lower statistical power. Additionally, we have performed an evaluation of visual food stimuli chosen by patients diagnosed with anorexia nervosa. They have selected images of the most and the least willingly eaten meals. Although they didn't know the exact calorie content, they chose intuitively photos later classified as extremely high- or low-caloric.

Attachment Trauma Is Associated with White Matter Fiber Microstructural Alterations in Adolescents with Anorexia Nervosa before and after Exposure to Psychotherapeutic and Nutritional Treatment.

In the present study, we explore the role of attachment for microstructural white matter (WM) changes in adolescents with anorexia nervosa (AN) before and after exposure to short-term and nutritional treatment. The case sample consisted of 22 female adolescent inpatients with AN (mean age: 15.2 ± 1.2 years) and the control sample were 18 gender-matched healthy adolescents (mean age: 16.8 ± 0.9 years). We performed a 3T MRI in the patient group during the acute state of AN and after weight restoration (duration: 2.6 ± 1 months) and compared the data to a healthy control group. To classify attachment patterns, we used the Adult Attachment Projective Picture System. In the patient sample, over 50% were classified with an attachment trauma/unresolved attachment status. Prior to treatment exposure, fractional anisotropy (FA) reductions and concordant mean diffusivity (MD) increases were evident in the fornix, the corpus callosum and WM regions of the thalamus, which normalized in the corpus callosum and the fornix post-therapy in the total patient sample (p < 0.002). In the acute state, patients with an attachment trauma demonstrated significant FA decreases compared to healthy controls, but no MD increases, in the corpus callosum and cingulum bilaterally, which remained decreased after therapy. Attachment patterns seem to be associated with region-specific changes of WM alterations in AN.

SLM-based off-axis Fourier filtering in microscopy with white light illumination.

In various microscopy applications spatial light modulators (SLMs) are used as programmable Fourier filters to realize different optical contrast enhancement methods. It is often advantageous to use the SLM in off-axis configuration, where the filtered image wave is sent into the first diffraction order of a blazed grating superposed to the phase mask on the SLM. Because of dispersion this approach is, however, typically limited to spectrally narrowband illumination. Here we suggest a method involving a grating for pre-compensation, which allows one to use spectrally broadband (even thermal) light in SLM-based Fourier filtering. The proposed approach is demonstrated by multicolor imaging of amplitude and phase objects, such as a resolution target, onion epidermal cells and human epithelial cheek cells.

Investigating the Migraine Cycle over 21 Consecutive Days Using Proton Magnetic Resonance Spectroscopy and Resting-State fMRI: A Pilot Study.

Recent neuroimaging studies have revealed important aspects of the underlying pathophysiological mechanisms of migraine suggesting abnormal brain energy metabolism and altered functional connectivity. Proton magnetic resonance spectroscopy (1H-MRS) studies investigated migraine patients in the interictal or ictal state. This first-of-its-kind study aimed to investigate the whole migraine cycle using 1H-MRS and resting-state functional magnetic resonance imaging (fMRI). A migraine patient underwent 1H-MRS and resting-state fMRI for 21 consecutive days, regardless of whether he was in an interictal or ictal state. Metabolite ratios were assessed and compared to the intrinsic connectivity of subcortical brain areas. Probable migraine phase-dependent changes in N-acetyl aspartate (NAA)/total creatine (tCr) and choline (Cho)/tCr levels are found in the left occipital lobe and left basal ganglia. NAA reflects neuronal integrity and Cho cellular membrane turnover. Such abnormalities may increase the susceptibility to excitatory migraine triggers. Functional connectivity between the right hippocampus and right or left pallidum was strongly correlated to the NAA/Cho ratio in the right thalamus, suggesting neurochemical modulation of these brain areas through thalamic connections. To draw statistically significant conclusions a larger cohort is needed.

Characterization and diagnostic potential of R2* in early-stage progressive supranuclear palsy variants.

INTRODUCTION: Iron accumulation in subcortical brain nuclei has been shown to be differentially increased in atypical parkinsonian disorders. It is unclear whether the patterns of iron accumulation are consistent between variants of progressive supranuclear palsy (PSP) and their diagnostic utility in early to moderately advanced stages of the diseases. METHODS: Brain iron content (R2*) was quantified using magnetic resonance imaging in patients clinically diagnosed as PSP - parkinsonism (PSP-P, n = 15), PSP - Richardson's syndrome (PSP-RS, n = 14), Parkinson's disease (PD, n = 15), or the parkinsonian variant of multiple system atrophy (MSA-P, n = 14) using established criteria, and healthy controls (HC). Disease duration was less than 5 years in all patients. The quantification of regional R2* was performed using a semi-automatized approach. RESULTS: Significant group differences in R2*, primarily within the red nucleus and the substantia nigra, were identified between PSP, PD, MSA-P, and HC, but not between PSP-P and PSP-RS. However, distinct R2* correlation patterns across brain regions were observed for the different groups. Good classification performances (sensitivity and specificity >80%) were only obtained for PSP vs. HC. For all other comparisons, sensitivity and/or specificity was below <70%. CONCLUSION: Iron accumulation in subcortical brain nuclei has distinct correlated patterns in PSP-P and PSP-RS, which could be reflecting different pathophysiological mechanisms. Increased iron content in these nuclei appears to be a predictor for atypical parkinsonian disorders such as PSP and MSA. Further studies are required to reproduce this finding and elucidate the evolution of these patterns over the course of the disease.

Qualitative and Quantitative Comparison of Hippocampal Volumetric Software Applications: Do All Roads Lead to Rome?

Brain volumetric software is increasingly suggested for clinical routine. The present study quantifies the agreement across different software applications. Ten cases with and ten gender- and age-adjusted healthy controls without hippocampal atrophy (median age: 70; 25-75% range: 64-77 years and 74; 66-78 years) were retrospectively selected from a previously published cohort of Alzheimer's dementia patients and normal ageing controls. Hippocampal volumes were computed based on 3 Tesla T1-MPRAGE-sequences with FreeSurfer (FS), Statistical-Parametric-Mapping (SPM; Neuromorphometrics and Hammers atlases), Geodesic-Information-Flows (GIF), Similarity-and-Truth-Estimation-for-Propagated-Segmentations (STEPS), and Quantib™. MTA (medial temporal lobe atrophy) scores were manually rated. Volumetric measures of each individual were compared against the mean of all applications with intraclass correlation coefficients (ICC) and Bland-Altman plots. Comparing against the mean of all methods, moderate to low agreement was present considering categorization of hippocampal volumes into quartiles. ICCs ranged noticeably between applications (left hippocampus (LH): from 0.42 (STEPS) to 0.88 (FS); right hippocampus (RH): from 0.36 (Quantib™) to 0.86 (FS). Mean differences between individual methods and the mean of all methods [mm3] were considerable (LH: FS -209, SPM-Neuromorphometrics -820; SPM-Hammers -1474; Quantib™ -680; GIF 891; STEPS 2218; RH: FS -232, SPM-Neuromorphometrics -745; SPM-Hammers -1547; Quantib™ -723; GIF 982; STEPS 2188). In this clinically relevant sample size with large spread in data ranging from normal aging to severe atrophy, hippocampal volumes derived by well-accepted applications were quantitatively different. Thus, interchangeable use is not recommended.