Histological studies have suggested differing involvement of the hippocampal subfields in ageing and in Alzheimer's disease. The aim of this study was to assess in vivo local hippocampal changes in ...ageing and Alzheimer's disease based on high resolution MRI at 3 Tesla. T1-weighted images were acquired from 19 Alzheimer's disease patients age 76 ± 6 years, three males, Mini-Mental State Examination 13 ± 4 and 19 controls (age 74 ± 5 years, 11 males, Mini-Mental State Examination 29 ± 1). The hippocampal formation was isolated by manual tracing. Radial atrophy mapping was used to assess group differences and correlations by averaging hippocampal shapes across subjects using 3D parametric surface mesh models. Percentage difference, Pearson's r, and significance maps were produced. Hippocampal volumes were inversely correlated with age in older healthy controls (r = 0.56 and 0.6 to the right and left, respectively, P < 0.05, corresponding to 14% lower volume for every 10 years of older age from ages 65 to 85 years). Ageing-associated atrophy mapped to medial and lateral areas of the tail and body corresponding to the CA1 subfield and ventral areas of the head corresponding to the presubiculum. Significantly increased volume with older age mapped to a few small spots mainly located to the CA1 sector of the right hippocampus. Volumes were 35% and 30% smaller in Alzheimer's disease patients to the right and left (P < 0.0005). Alzheimer's disease-associated atrophy mapped not only to CA1 areas of the body and tail corresponding to those also associated with age, but also to dorsal CA1 areas of the head unaffected by age. Regions corresponding to the CA2–3 fields were relatively spared in both ageing and Alzheimer's disease. Hippocampal atrophy in Alzheimer's disease maps to areas in the body and tail that partly overlap those affected by normal ageing. Specific areas in the anterior and dorsal CA1 subfield involved in Alzheimer's disease were not in normal ageing. These patterns might relate to differential neural systems involved in Alzheimer's disease and ageing.
Clinical observations have suggested that the neuropsychological profile of early and late onset forms of Alzheimer's disease (EOAD and LOAD) differ in that neocortical functions are more affected in ...the former and learning in the latter, suggesting that they might be different diseases. The aim of this study is to assess the brain structural basis of these observations, and test whether neocortical areas are more heavily affected in EOAD and medial temporal areas in LOAD. Fifteen patients with EOAD and 15 with LOAD (onset before and after age 65; Mini Mental State Examination 19.8, SD 4.0 and 20.7, SD 4.2) were assessed with a neuropsychological battery and high-resolution MRI together with 1:1 age- and sex-matched controls. Cortical atrophy was assessed with cortical pattern matching, and hippocampal atrophy with region-of-interest-based analysis. EOAD patients performed more poorly than LOAD on visuospatial, frontal-executive and learning tests. EOAD patients had the largest atrophy in the occipital 25% grey matter (GM) loss in the left and 24% in the right hemisphere and parietal lobes (23% loss on both sides), while LOAD patients were remarkably atrophic in the hippocampus (21 and 22% loss). Hippocampal GM loss of EOAD (9 and 16% to the left and right) and occipital (12 and 14%) and parietal (13 and 12%) loss of LOAD patients were less marked. In EOAD, GM loss of 25% or more was mapped to large neocortical areas and affected all lobes, with relative sparing of primary sensory, motor, and visual cortex, and anterior cingulate and orbital cortex. In LOAD, GM loss was diffusely milder (below 15%); losses of 15-20% were confined to temporoparietal and retrosplenial cortex, and reached 25% in restricted areas of the medial temporal lobe and right superior temporal gyrus. These findings indicate that EOAD and LOAD differ in their typical topographic patterns of brain atrophy, suggesting different predisposing or aetiological factors.
Psoriasis is frequently associated with cardiometabolic comorbidities and depression that are risk factors for cognitive impairment.
To investigate cognitive performance in psoriatic patients.
...Cognitive performances were assessed by neuropsychological tests in 41 patients with psoriasis and 37 controls. Diagnostic criteria for mild cognitive impairment (MCI) were (1) subjective complaint of a memory deficit, confirmed by a relative or caregiver, (2) pathological performance on neuropsychological tests investigating cognitive domains, (3) normal performance of daily living activities and (4) no dementia. Neuroimaging was studied by high-field magnetic resonance imaging and cortical thickness analysis.
MCI was found in 18 out of 41 (44%) patients with psoriasis compared to 4 out of 37 (11%) controls (p = 0.002). In particular, patients with psoriasis had lower scores in the delayed recall of the Rey Auditory Verbal Learning Test (p = 0.04), Backwards Digit Span Test (p = 0.002), Weigl's Sorting Test (p = 0.01) and Trail Making Test B (p = 0.008). In the 7 patients submitted to cortical thickness analysis, a reduction in brain thickness in parahippocampal, superior temporal and frontal gyri of the left hemisphere was observed.
Patients with psoriasis may have a precocious impairment of long-term verbal memory, executive functions and attention.
To date, limited data are available regarding the inter-site consistency of test–retest reproducibility of functional connectivity measurements, in particular with regard to integrity of the Default ...Mode Network (DMN) in elderly participants. We implemented a harmonized resting-state fMRI protocol on 13 clinical scanners at 3.0T using vendor-provided sequences. Each site scanned a group of 5 healthy elderly participants twice, at least a week apart. We evaluated inter-site differences and test–retest reproducibility of both temporal signal-to-noise ratio (tSNR) and functional connectivity measurements derived from: i) seed-based analysis (SBA) with seed in the posterior cingulate cortex (PCC), ii) group independent component analysis (ICA) separately for each site (site ICA), and iii) consortium ICA, with group ICA across the whole consortium. Despite protocol harmonization, significant and quantitatively important inter-site differences remained in the tSNR of resting-state fMRI data; these were plausibly driven by hardware and pulse sequence differences across scanners which could not be harmonized. Nevertheless, the tSNR test–retest reproducibility in the consortium was high (ICC=0.81). The DMN was consistently extracted across all sites and analysis methods. While significant inter-site differences in connectivity scores were found, there were no differences in the associated test–retest error. Overall, ICA measurements were more reliable than PCC-SBA, with site ICA showing higher reproducibility than consortium ICA. Across the DMN nodes, the PCC yielded the most reliable measurements (≈4% test–retest error, ICC=0.85), the medial frontal cortex the least reliable (≈12%, ICC=0.82) and the lateral parietal cortices were in between (site ICA). Altogether these findings support usage of harmonized multisite studies of resting-state functional connectivity to characterize longitudinal effects in studies that assess disease progression and treatment response.
•We implement a multi-site 3T MRI protocol for resting state fMRI in 13 sites.•We acquire across-session test–retest (TRT) data on 64 healthy elderly participants.•Despite harmonization strong phantom and brain tSNR differences remain across sites.•TRT error of regional DMN functional connectivity is consistent across sites.•ICA yields more reliable DMN connectivity measurements relative to SBA.
This case report describes the clinical, imaging, and pathological features of a case of Langerhans cell histiocytosis affecting a patient suffering from chronic thoracic spine pain. Spinal ...localizations of Langerhans cell histiocytosis have been rarely described and they are usually characterized by involvement of vertebral bodies with osteolytic lesions. Our case presented with several unusual features that delayed the diagnosis, including the age of patient and the involvement of left T10 costovertebral junction with relative sparing of vertebral body and costal bone. The clues for diagnosis were represented by increased signal intensity both on
W fat-saturated and
W images after administration of gadolinium. The diagnosis was finally confirmed by means of percutaneous biopsy with subsequent histological/immunohistochemical study.
•IDH mutation is an important genetic marker in natural history of gliomas (WHO 2016).•DTI metrics can help to analyze IDH1 mutation status in HGG.•RD and MD can help to discriminate between HGG IDH1 ...wild-type and HGG IDH1 mutated.
To evaluate any possible correlation between the presence of Isocitrate DeHydrogenase 1 mutation (IDH1m) and specific DTI (Diffusion Tensor Imaging) metrics, such as Fractional Anisotropy (FA), Mean Diffusivity (MD), Radial Diffusivity (RD) and Axial Diffusivity (AD).
We retrospectively analyzed 47 patients who underwent an advanced-MR study with DTI followed by surgical intervention with a subsequent histologic diagnosis of High-Grade Glioma (HGG) and immunohistochemical evaluation of IDH1 (Isocitrate DeHydrogenase) mutation status. For each DTI metrics we measured the ratio between tumor and normal tissue and we evaluated the correlation with IDH1 mutation.
We observed a positive correlation with IDH1 status and RD and MD data. No correlation was demonstrated between IDH1 status and FA and AD.
Our results support the hypothesis that the number of residual axonal fibers, extracellular matrix composition and the presence of colliquated tissue, may together contribute to a global RD increase in HGG, with a relatively higher increase in IDH1m tumors.
Our data are in favor of a need for multimodal advance evaluation of HGG. DTI metrics help to analyze IDH1 mutation status, in order to better characterize the lesions and to tailor treatment and follow up.
Blood oxygen level dependent (BOLD) contrast is influenced by some physiological factors such as blood flow and blood volume that can be a source of variability in fMRI analysis. Previous studies ...proposed to use the cerebrovascular response data to normalize or calibrate BOLD maps in order to reduce variability of fMRI data both among brain areas in single subject analysis and across subjects. Breath holding is one of the most widely used methods to investigate the vascular reactivity. However, little is known about the robustness and reproducibility of this procedure. In this study we investigated three different breath holding periods. Subjects were asked to hold their breath for 9, 15 or 21 s in three separate runs and the fMRI protocol was repeated after 15 to 20 days. Our data show that the BOLD response to breath holding after inspiration results in a complex shape due to physiological factors that influence the signal variation with a timing that is highly reproducible. Nevertheless, the reproducibility of the magnitude of the cerebrovascular response to CO2, expressed as amplitude of BOLD signal and number of responding voxels, strongly depends on duration of breath holding periods. Breath holding period of 9 s results in high variability of the magnitude of the response while longer breath holding durations produce more robust and reproducible BOLD responses.
Large-scale longitudinal neuroimaging studies with diffusion imaging techniques are necessary to test and validate models of white matter neurophysiological processes that change in time, both in ...healthy and diseased brains. The predictive power of such longitudinal models will always be limited by the reproducibility of repeated measures acquired during different sessions. At present, there is limited quantitative knowledge about the across-session reproducibility of standard diffusion metrics in 3T multi-centric studies on subjects in stable conditions, in particular when using tract based spatial statistics and with elderly people. In this study we implemented a multi-site brain diffusion protocol in 10 clinical 3T MRI sites distributed across 4 countries in Europe (Italy, Germany, France and Greece) using vendor provided sequences from Siemens (Allegra, Trio Tim, Verio, Skyra, Biograph mMR), Philips (Achieva) and GE (HDxt) scanners. We acquired DTI data (2×2×2mm3, b=700s/mm2, 5 b0 and 30 diffusion weighted volumes) of a group of healthy stable elderly subjects (5 subjects per site) in two separate sessions at least a week apart. For each subject and session four scalar diffusion metrics were considered: fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial (AD) diffusivity. The diffusion metrics from multiple subjects and sessions at each site were aligned to their common white matter skeleton using tract-based spatial statistics. The reproducibility at each MRI site was examined by looking at group averages of absolute changes relative to the mean (%) on various parameters: i) reproducibility of the signal-to-noise ratio (SNR) of the b0 images in centrum semiovale, ii) full brain test–retest differences of the diffusion metric maps on the white matter skeleton, iii) reproducibility of the diffusion metrics on atlas-based white matter ROIs on the white matter skeleton. Despite the differences of MRI scanner configurations across sites (vendors, models, RF coils and acquisition sequences) we found good and consistent test–retest reproducibility. White matter b0 SNR reproducibility was on average 7±1% with no significant MRI site effects. Whole brain analysis resulted in no significant test–retest differences at any of the sites with any of the DTI metrics. The atlas-based ROI analysis showed that the mean reproducibility errors largely remained in the 2–4% range for FA and AD and 2–6% for MD and RD, averaged across ROIs. Our results show reproducibility values comparable to those reported in studies using a smaller number of MRI scanners, slightly different DTI protocols and mostly younger populations. We therefore show that the acquisition and analysis protocols used are appropriate for multi-site experimental scenarios.
•We implement a multi-site 3T MRI protocol for brain DTI on 10 EU sites.•We acquire across-session test–retest data on 50 healthy elderly subjects.•We use full brain TBSS and ROI analysis to calculate FA, MD, RD and AD.•Reproducibility errors are in the 2–6% range.•Reproducibility errors tended to be lower in sites with shorter acquisitions.
To evaluate the reliability of magnetic resonance imaging performed after intratympanic gadolinium administration in evidencing endolymphatic hydrops in patients with Ménière's disease (MD).
A total ...of 26 patients (18 male and 8 female subjects, aged 25-78 yr; median age, 56 yr) with definite MD and 12 subjects (8 male and 4 female subjects, aged 31-75 yr; median age, 51 yr) with various unilateral non-MD disorders of the inner ear were examined.
A 0.6-ml solution of gadobutrol (1 mmol/ml), diluted 1:7 in saline, was injected in the affected ear through the inferior-posterior quadrant of the tympanic membrane, using a 22-gauge spinal needle. In 9 MD patients, the contralateral ear also was injected. The patient was kept with the head rotated 45 degrees contralaterally for 30 minutes after each injection. Twenty-four hours later, a 3-dimensional fluid-attenuated inversion recovery magnetic resonance imaging using a 3 Tesla unit was performed.
Perilymphatic enhancement was evaluated in different portions of the labyrinth in MD ears and compared with the outcomes obtained in the non-MD ears.
All MD ears showed impaired perilymphatic enhancement of variable degrees. No enhancement defects could be observed in all examined contralateral unaffected ear of the patients with MD, as well as in 11 of the 12 ears of the subjects with various unilateral non-MD disorders.
Perilymphatic enhancement defect of variable degrees is observed in the pathologic ear of every patient with MD. The consistency of this phenomenon in MD ears and the complete enhancement in most of the ears without MD safely enable to attribute these findings to endolymphatic hydrops. It is likely in the near future that imaging may be used to achieve a certain diagnosis of MD in life.
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