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In memory of Marco Leonardi

Mario Muto, Alberto Beltramello
2017 Neuroradiology  
Mario Muto, Alberto Beltramello  ... 
doi:10.1007/s00234-017-1842-y pmid:28597207 fatcat:rkjpiiisn5bzhlxaclcp3vlx6q

Advanced magnetic resonance imaging techniques in brain tumours surgical planning

Giada Zoccatelli, Franco Alessandrini, Alberto Beltramello, Andrea Talacchi
2013 Journal of Biomedical Science and Engineering  
Morphological assessment using Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) is still the workhorse of tumor detection and diagnosis. In particular, MRI provides detailed information about cerebral tumor anatomy, cellular metabolism and hemodynamic features, making it a fundamental tool for a correct diagnosis, treatment and monitoring of the disease. Various new functional imaging modalities assessing tissue microstructure and physiology have increased the scope of neuro imaging
more » ... and raised expectations among clinicians. This article provides an overview of the most advanced MR imaging techniques (functional MRI, perfusion-weighted imaging, diffusion-weighted imaging and MR spectroscopy) now available for neurosurgical planning and their role in brain tumors assessment. Their pros and cons are analyzed in order to find out which one may be chosen as best diagnostic pre-surgical protocol. At the moment none of the single techniques can be considered the golden standard; only the integration of advanced and conventional MR imaging proves to be a reliable tool in the hands of the neuroradiologist and neurosurgeon, thus maximazing tumor resection and function preservation.
doi:10.4236/jbise.2013.63a051 fatcat:yrgo3ve75bfpfnu723lpbi7rda

Progression of Endolymphatic Hydrops in Ménière's Disease as Evaluated by Magnetic Resonance Imaging

Francesco Fiorino, Francesca B. Pizzini, Alberto Beltramello, Franco Barbieri
2011 Otology and Neurotology  
Objective: To evaluate the presence and the degree of endolymphatic hydrops (EHs) in patients with unilateral Ménière's disease (MD), as a function of duration of the disease, estimated using a 3-dimensional fluid-attenuated inversion recovery sequence in a 3-Tesla magnetic resonance imaging unit, after intratympanic gadolinium administration. Patients: A total of 32 patients (21 male and 11 female subjects, aged 25Y78 yr; median, 56 yr) participated in the investigation. The duration of the
more » ... ease ranged from 2 months to 10 years (median, 3 yr), with a prevalence of vertigo spells in the last 6 months ranging from 0.5 to 8 per month (median, 2.5). Intervention: 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. The patient was kept with the head rotated 45 degrees contralaterally for 30 minutes after each injection. Twenty-four hours later, a 3-dimensional fluidattenuated inversion recovery magnetic resonance imaging was performed. Main Outcome Measure: Perilymphatic enhancement was evaluated in different portions of the labyrinth as a function of MD duration. Results: Reduced or absence of enhancement of the vestibule occurred precociously and occurred in all subjects at long term. The prevalence of enhancement abnormalities in the cochlea and the semicircular canals was directly proportional to MD duration. At long term, the vestibule and the cochlea showed a more severe hydropic involvement compared with semicircular canals. A statistical significant correlation between enhancement abnormalities and MD duration was observed for most inner ear sites. Conclusion: The increased prevalence and severity of EH with the duration of MD indicates that hydrops is a progressive degenerative phenomenon. The frequent abnormality in the vestibule and, secondarily, in the cochlea is in line with some histopathologic investigations. It remains to be clarified whether hydropic changes are related to specific signs and symptoms of MD.
doi:10.1097/mao.0b013e31822a1ce2 pmid:21817938 fatcat:vkze7f3rhjhshe4s35qwrsovae

Enlarged hypothalamic volumes in schizophrenia

Stefania Tognin, Gianluca Rambaldelli, Cinzia Perlini, Marcella Bellani, Veronica Marinelli, Giada Zoccatelli, Franco Alessandrini, Francesca Benedetta Pizzini, Alberto Beltramello, Robert Terlevic, Michele Tansella, Matteo Balestrieri (+1 others)
2012 Psychiatry Research : Neuroimaging  
Hypothalamic abnormalities in schizophrenia have been associated with endocrine dysfunctions and stress response. The hypothalamus is involved in several pathways found disrupted in schizophrenia (e.g. hypothalamic-pituitary-adrenal axis, HPA axis); however the available results on potential structural hypothalamic alterations are still controversial. The aim of the study was to investigate the volumes of the hypothalamus and the mammillary bodies in patients with schizophrenia and healthy
more » ... ols. Twenty-six patients with schizophrenia and 26 healthy controls underwent a 3 Tesla magnetic resonance imaging (MRI) scan. Hypothalamus and mammillary bodies were manually traced by a rater who was blind to subjects' identity. The General Linear Model was used in group comparisons of the volumes of the hypothalamus and the mammillary bodies. The hypothalamus and mammillary body volumes were significantly larger in patients with schizophrenia than controls, with significant enlargement of the left hypothalamus and trends for significantly increased right hypothalamus and right mammillary body. The size of the mammillary bodies was inversely correlated with negative symptoms and directly correlated with anxiety. This study showed abnormally increased sizes of the hypothalamus and the mammillary bodies in schizophrenia. Mammillary bodies volumes were associated to negative symptoms and anxiety. Future longitudinal studies on the volumes of the hypothalamus and the mammillary bodies with respect to the levels of related hormones will clarify their role in modulating HPA axis in schizophrenia.
doi:10.1016/j.pscychresns.2012.10.006 pmid:23217575 fatcat:uftjio4qtbd3zaa5g33bmgfbeu

Clinical characteristics of frontotemporal patients with symmetric brain atrophy

Marina Boccardi, Lorena Bresciani, Cristina Geroldi, Alberto Beltramello, Giovanni B. Frisoni, Mikko P. Laakso
2002 European Archives of Psychiatry and Clinical Neuroscience  
Laakso · Lorena Bresciani · Cristina Geroldi · Alberto Beltramello · Giovanni B. Frisoni Clinical characteristics of frontotemporal patients with symmetric brain atrophy 20].  ... 
doi:10.1007/s00406-002-0388-z pmid:12451466 fatcat:46y54xqdr5cwnlasrd7ltzcemy

The topography of grey matter involvement in early and late onset Alzheimer's disease

Giovanni B. Frisoni, Michela Pievani, Cristina Testa, Francesca Sabattoli, Lorena Bresciani, Matteo Bonetti, Alberto Beltramello, Kiralee M. Hayashi, Arthur W. Toga, Paul M. Thompson
2007 Brain  
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
more » ... 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.
doi:10.1093/brain/awl377 pmid:17293358 fatcat:m3uyjreffvemtjgjeu74dvlxj4

The Role of Brain MRI in Mitochondrial Neurogastrointestinal Encephalomyopathy

Mauro Scarpelli, Giuseppe Kenneth Ricciardi, Alberto Beltramello, Isabella Zocca, Francesca Calabria, Anna Russignan, Francesca Zappini, Maria Sofia Cotelli, Alessandro Padovani, Giuliano Tomelleri, Massimiliano Filosto, Paola Tonin
2013 The Neuroradiology Journal  
Leukoencephalopathy is a hallmark of mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) a devastating disorder characterized by ptosis, ophthalmoparesis, gastrointestinal dysfunction and polyneuropathy. To characterize MNGIE-associated leukoencephalopathy and to correlate it with clinical, biochemical and molecular data, four MNGIE patients with heterogeneous clinical phenotypes (enteropathic arthritis, exercise intolerance, CIDP-like phenotype and typical presentation) were studied
more » ... y magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Diffusion weighted imaging (DWI) with apparent diffusion coefficient (ADC) maps were also obtained. In two patients we also investigated the role of brain MRI in monitoring the evolution of leukoencephalopathy by performing follow-up imaging studies at an interval of one and two years. The extension and distribution of leukoencephalopathy were not clearly linked with age, phenotype or disease severity, and did not seem to be related to TYMP mutations, enzyme activity or pyrimidine levels. In the studied patients MRS revealed reduced N-acetyl-aspartate and increased choline signals. Although DWI appeared normal in all patients but one, ADC maps always showed moderate increased diffusivity. Leukoencephalopathy worsened over a two-year period in two patients, regardless of the clinical course, indicating a lack of correlation between clinical phenotype, size and progression of white matter abnormalities during this period. Brain MRI should be considered a very useful tool to diagnose both classical and atypical MNGIE. Serial MRIs in untreated and treated MNGIE patients will help to establish whether the leukoencephalopathy is a reversible condition or not.
doi:10.1177/197140091302600505 pmid:24199812 pmcid:PMC4202835 fatcat:m7lbyt42kfe6hi46ychx4ums2i

Hippocampus and entorhinal cortex in frontotemporal dementia and Alzheimer's disease: a morphometric MRI study

Mikko P. Laakso, Giovanni B. Frisoni, Mervi Könönen, Mia Mikkonen, Alberto Beltramello, Claudia Geroldi, Angelo Bianchetti, Marco Trabucchi, Hilkka Soininen, Hannu J. Aronen
2000 Biological Psychiatry  
Magnetic resonance imaging (MRI) of hippocampal atrophy is a sensitive but not specific method to support the clinical diagnosis of early Alzheimer's disease (AD). We recently described our findings that atrophy of the entorhinal cortex (ERC) in frontotemporal dementia (FTD) is equal to that found in AD but that hippocampal atrophy in FTD is less than that found in AD. The MRI volumes of these structures provide a topographic representation of the region of interest. We hypothesized that two
more » ... ferent dementias with distinct histopathologic and clinical features might, in addition to quantitative patterns, display topographically different patterns of atrophy. Methods: We adopted a morphometric approach to monitor the pattern of atrophy of the hippocampus and the ERC by computing two-dimensional profiles from MRI volumes of the structures in control subjects and patients with FTD and AD. Results: Compared with control subjects, atrophy of the hippocampus in patients with AD was diffuse. In patients with FTD, atrophy of the hippocampus was localized predominantly in the anterior hippocampus, suggesting a different pattern of hippocampal atrophy in FTD compared with AD. The amount and pattern of atrophy of the entorhinal cortex was virtually equal in both demented groups. Conclusions: This study provides novel data on the nature of medial temporal lobe atrophy in FTD. Morphometric MRI may be a useful technique for characterizing different patterns of atrophy in primary degenerative dementias in vivo.
doi:10.1016/s0006-3223(99)00306-6 pmid:10862805 fatcat:aauh5whjabdqdclxfvr7p4mn4i

Effect of Memantine on Resting State Default Mode Network Activity in Alzheimer's Disease

Marco Lorenzi, Alberto Beltramello, Nicola B. Mercuri, Elisa Canu, Giada Zoccatelli, Francesca B. Pizzini, Franco Alessandrini, Maria Cotelli, Sandra Rosini, Daniela Costardi, Carlo Caltagirone, Giovanni B. Frisoni
2011 Drugs & Aging  
Background. Memantine is an approved symptomatic treatment for moderate to severe Alzheimer's Disease(AD) active on the excitotoxic effects of hyperactive glutamatergic transmission. The mechanism of the effect of memantine in AD patients is poorly known. The default mode network (DMN) is hypoactive in AD and is under glutamatergic control. Objective. To assess the effect of memantine on the activity of the DMN in moderate to severe AD. Methods. fMRI data of 15 moderate to severe AD patients, 7
more » ... (age 77±7, MMSE 16±4) treated with memantine and 8 with placebo (age 75±6, MMSE 13±4), were acquired at baseline (T0) and after 6 months of treatment (T6). Resting state components were extracted after spatial normalization on individual patients with independent component analysis. The consistency of the components was assessed using ICASSO and the DMN was recognized through spatial correlation with a predefined template. Voxel-based statistical analyses were performed to study the change of DMN activity from T0 to T6 in the two groups. Results. At T0, the two groups showed similar DMN activity except in the precuneus, where the treated showed slightly greater activity (p<0.05 corrected for family wise error). The prospective comparison between T0 and T6 in the treated showed increased DMN activation mapping to the precuneus (p<0.05 corrected), while the prospective comparison in the untreated did not show significant changes. The treatment x time interaction term was significant at p<0.05 corrected. Conclusions. The results suggest a positive effect of Memantine treatment in moderate to severe AD patients resulting in an increased resting activity in the precuneus region over 6 months. Future confirmatory analysis with adequately powered studies will be required to support the present findings. Disclosure/Conflict of Interest This work has been co-funded by research grant N. 125/2004 of the Italian Ministry of Health, Ricerca Finalizzata "Malattie neurodegenerative legate all'invecchiamento: dalla patogenesi alle prospettive terapeutiche per un progetto traslazionale" and by an unrestricted grant by Lundbeck Italia SpA Pharmaceutical.
doi:10.2165/11586440-000000000-00000 pmid:21250762 fatcat:ioakyauepjfgblqyfwvd5m2jm4

A comparison between the accuracy of voxel-based morphometry and hippocampal volumetry in Alzheimer's disease

Cristina Testa, Mikko P. Laakso, Francesca Sabattoli, Roberta Rossi, Alberto Beltramello, Hilkka Soininen, Giovanni B. Frisoni
2004 Journal of Magnetic Resonance Imaging  
Purpose: To compare the accuracy of voxel-based morphometry (VBM) and region of interest (ROI)-based hippocampal volumetry to detect medial temporal lobe atrophy in Alzheimer's disease (AD). Materials and Methods: A total of 27 AD patients (age 74 Ϯ 9 years; 22 women; Mini-Mental State Exam [MMSE] 21 Ϯ 4) and 25 controls (age 70 Ϯ 8; 16 women; MMSE 29 Ϯ 1) were studied. Accuracy of VBM to detect gray matter loss in those seven AD patients and 11 controls with similar ROIbased hippocampal
more » ... s and of ROI-based volumetry to detect gray matter loss in those four AD patients and five controls with similar VBM-based hippocampal measures was assessed. VBM was performed with statistical parametric mapping (SPM99). Results: The area under the curve was 0.96 (95% C.I., 0.92-1.00) for VBM, 0.89 (95% C.I., 0.80 -0.98) for ROIbased hippocampal measures, and 0.99 (95% C.I., 0.96 -1.00) for both. In subjects with similar ROI-based hippocampal measures, VBM detected atrophy in AD patients at P Ͻ 0.0001, while in subjects with similar VBM-based hippocampal measure, volumetry was not significant (P ϭ 0.11). Both measures independently contributed to discrimination (P ϭ 0.004 and P ϭ 0.032) in a logistic regression model. Conclusion: These results indicate that VBM is more accurate, but the combination of both methods provides the highest accuracy for detection of hippocampal atrophy in AD.
doi:10.1002/jmri.20001 pmid:14994294 fatcat:s7xvm35xsvhwjer4xlig3unlxy

Degenerative spine disease: Italian position paper on acquisition, interpretation and reporting of Magnetic Resonance Imaging

Francesca B. Pizzini, Mattia Poletti, Alberto Beltramello, Mario Muto, Alessandra Splendiani, Sara Mehrabi, Giuseppe Costanzo, Vincenzo Vitiello, Antonio Barile, Stefano Colagrande, Giancarlo Mansueto, Stefano Bastianello
2021 Insights into Imaging  
Objective To promote a better radiological interpretation of spine degeneration, a consistent standardization of the acquisition, interpretation and description of Magnetic Resonance Imaging (MRI) l findings. Materials and methods In order to achieve this objective, a consensus among experts in imaging of degenerative spine disease (DSD) from Italian radiological societies (SIRM—Italian Society of Radiology, AINR—Italian Association of Neuroradiology) was achieved. The representatives of the
more » ... lian inter-societal working group examined the literature produced by European/American task forces on optimizing the study sequences, classification of degenerative disc changes, spondylo-arthrosis, osteochondrosis, synovial and ligament pathologies of the spinal column, and on canal and foraminal stenosis. The document-resulted from the consensus between experts—was then presented to the scientific societies of Neurosurgery (SINCH) and Orthopedics and Traumatology (SIOT) for their approval. Results This position paper presents a proposal for an optimized MRI protocol for studying DSD and provides a glossary of terms related to this pathology and indications on their use. The international terminological recommendations have been translated and adapted to the Italian language and clinical practice and clinical cases have been used to illustrate some of the main classifications. Conclusions This revision of international DSD guidelines/recommendations and consensus made it possible to (1) update the nomenclature to international standards and (2) harmonize the MRI protocol and description of radiological findings, adapting both (1, 2) to the Italian context. With this position paper we intend to contribute to an improvement of the communication among doctors and between physicians and their patients as well as the quality of the radiological reports.
doi:10.1186/s13244-020-00952-w pmid:33575851 fatcat:izn5e5xtyvgdnigwl2vpnbcxgy

Diffuse alterations in grey and white matter associated with cognitive impairment in Shwachman–Diamond syndrome: Evidence from a multimodal approach

Sandra Perobelli, Franco Alessandrini, Giada Zoccatelli, Elena Nicolis, Alberto Beltramello, Baroukh M. Assael, Marco Cipolli
2015 NeuroImage: Clinical  
Shwachman-Diamond syndrome is a rare recessive genetic disease caused by mutations in SBDS gene, at chromosome 7q11. Phenotypically, the syndrome is characterized by exocrine pancreatic insufficiency, bone marrow dysfunction, skeletal dysplasia and variable cognitive impairments. Structural brain abnormalities (smaller head circumference and decreased brain volume) have also been reported. No correlation studies between brain abnormalities and neuropsychological features have yet been
more » ... In this study we investigate neuroanatomical findings, neurofunctional pathways and cognitive functioning of Shwachman-Diamond syndrome subjects compared with healthy controls. To be eligible for inclusion, participants were required to have known SBDS mutations on both alleles, no history of cranial trauma or any standard contraindication to magnetic resonance imaging. Appropriate tests were used to assess cognitive functions. The static images were acquired on a 3 × 0 T magnetic resonance scanner and blood oxygen level-dependent functional magnetic resonance imaging data were collected both during the execution of the Stroop task and at rest. Diffusion tensor imaging was used to assess brain white matter. The Tract-based Spatial Statistics package and probabilistic tractography were used to characterize white matter pathways. Nine participants (5 males), half of all the subjects aged 9-19 years included in the Italian Shwachman-Diamond Syndrome Registry, were evaluated and compared with nine healthy subjects, matched for sex and age. The patients performed less well than norms and controls on cognitive tasks (p = 0.0002). Overall, cortical thickness was greater in the patients, both in the left (+10%) and in the right (+15%) hemisphere, significantly differently increased in the temporal (left and right, p = 0.04), and right parietal (p = 0.03) lobes and in Brodmann area 44 (p = 0.04) of the right frontal lobe. The greatest increases were observed in the left limbic-anterior cingulate cortex (≥43%, p b 0.0004). Only in Broca3s area in the left hemisphere did the patients show a thinner cortical thickness than that of controls (p = 0.01). Diffusion tensor imaging showed large, significant difference increases in both fractional anisotropy (+37%, p b 0.0001) and mean diffusivity (+35%, p b 0.005); the Tract-based Spatial Statistics analysis identified six abnormal clusters of white matter fibres in the fronto-callosal, right fronto-external capsulae, left fronto-parietal, right pontine, temporo-mesial and left anterior-medial-temporal regions. Brain areas activated during the Stroop task and those active during the resting state, are different, fewer and smaller in patients and correlate with worse performance (p = 0.002). Cognitive impairment in Shwachman-Diamond syndrome subjects is associated with diffuse brain anomalies in the grey matter (verbal skills with BA44 and BA20 in the right hemisphere; perceptual skills with BA5, 37, 20, 21, 42 in the left hemisphere) and white matter connectivity (verbal skills with alterations in the fronto-occipital fasciculus and with the inferior-longitudinal fasciculus; perceptual skills with the arcuate fasciculus, limbic and NeuroImage: Clinical 7 (2015) 721-731 ponto-cerebellar fasciculus; memory skills with the arcuate fasciculus; executive functions with the anterior cingulated and arcuate fasciculus).
doi:10.1016/j.nicl.2015.02.014 pmid:25844324 pmcid:PMC4375735 fatcat:alcfmdnw4faere3ycvzjvsvxze

Patient-Specific Detection of Cerebral Blood Flow Alterations as Assessed by Arterial Spin Labeling in Drug-Resistant Epileptic Patients

Ilaria Boscolo Galazzo, Silvia Francesca Storti, Alessandra Del Felice, Francesca Benedetta Pizzini, Chiara Arcaro, Emanuela Formaggio, Roberto Mai, Michael Chappell, Alberto Beltramello, Paolo Manganotti, Yoko Hoshi
2015 PLoS ONE  
Electrophysiological and hemodynamic data can be integrated to accurately and precisely identify the generators of abnormal electrical activity in drug-resistant focal epilepsy. Arterial Spin Labeling (ASL), a magnetic resonance imaging (MRI) technique for quantitative noninvasive measurement of cerebral blood flow (CBF), can provide a direct measure of variations in cerebral perfusion associated with the epileptic focus. In this study, we aimed to confirm the ASL diagnostic value in the
more » ... ication of the epileptogenic zone, as compared to electrical source imaging (ESI) results, and to apply a template-based approach to depict statistically significant CBF alterations. Standard video-electroencephalography (EEG), high-density EEG, and ASL were performed to identify clinical seizure semiology and noninvasively localize the epileptic focus in 12 drug-resistant focal epilepsy patients. The same ASL protocol was applied to a control group of 17 healthy volunteers from which a normal perfusion template was constructed using a mixed-effect approach. CBF maps of each patient were then statistically compared to the reference template to identify perfusion alterations. Significant hypo-and hyperperfused areas were identified in all cases, showing good agreement between ASL and ESI results. Interictal hypoperfusion was observed at the site of the seizure in 10/12 patients and early postictal hyperperfusion in 2/12. The epileptic focus was correctly identified within the surgical resection margins in the 5 patients who underwent lobectomy, all of which had good postsurgical outcomes. The combined use of ESI and ASL can aid in the noninvasive evaluation of drug-resistant epileptic patients. Multimodal approaches combining several imaging methods may further our understanding of the mechanisms underlying the epileptic process and aid in more accurately localizing abnormal neuronal activity, especially in patients with drug-resistant epilepsy [1] [2] . In such patients, the mainstay therapeutic option for reducing or suppressing seizures is surgical resection of the epileptogenic zone [3] [4] [5] . Therefore, precise preoperative localization of the epileptogenic zone is crucial to spare non-epileptogenic brain tissue as best as possible and minimize postoperative neurological deficits [6] . Although highly invasive and burdened by potential risks limiting its use in clinical settings [7] , invasive electroencephalography (EEG) (e.g., stereo-EEG [sEEG]) remains the gold standard to localize the epileptogenic focus when noninvasive presurgical evaluation fails to yield clear-cut information [8] [9] [10] . Noninvasive presurgical workup will usually include long-term EEG, video-EEG and neuropsychological testing, which do not always provide the localization accuracy and precision required for surgical planning. Morphological magnetic resonance imaging (MRI) scans are also routinely acquired in epileptic patients to identify structural brain lesions such as tumors, cortical dysplasia or hippocampal sclerosis, which can define the seizure onset zone and guide surgical resection [11] . In the absence of these findings, however, the MRI scans may be inconclusive for delineating the location of the focal abnormality and will therefore need to be integrated with complementary neuroimaging studies. Imaging techniques such as positron-emission tomography (PET) and single-photon emission computed tomography (SPECT) [12] [13] [14] [15] , dipole localization or electrical source imaging (ESI) [16] [17] [18] [19] , and EEG-functional MRI (fMRI) [20] [21] [22] [23] can all offer additional localization information and improve the yield of routine imaging studies. However, functional neuroimaging techniques (as PET, SPECT, fMRI), though each providing data on metabolism, perfusion, and blood oxygenation, have poor temporal resolution. Conversely, EEG, and high-density EEG (hdEEG) in particular, provide a direct measurement of neuronal activity with high temporal resolution which allows investigation of epileptic activity on a millisecond scale, from the initiation of seizure activity through to the propagation phase [24] . When combined, they can be used to evaluate the same phenomenon from different perspectives, overcoming the limitations inherent to each modality and thus obtain a more complete picture of the dynamics of the epileptic focus [25] [26] [27] [28] [29] . Since the 1980s, perfusion changes during epileptic processes have been investigated using SPECT in combination with technetium-99m hexamethyl-propylene amine oxime (Tc-99m HMPAO) or Tc-99m ethyl cysteinate dimer (Tc-99m ECD), especially during the ictal and postictal phases [30] . While ictal and postictal SPECT demonstrate high sensitivity in focus localization (97-100% and 75-77%, respectively), their sensitivity during the interictal phase is about 50% lower [31] [32] . Moreover, the technique has several limitations, including relatively low spatial resolution, high cost, and difficult logistics that restrict its availability to a few specialized neuroimaging centers [30] . In addition, the localization accuracy of SPECT during the ictal/early postictal phases depends critically on injecting the tracer as early as possible after seizure onset. If the timing is not precise, ambiguous blood flow changes may result, leading to misinterpretation of the main generator of seizure activity. Recently, newer MRI methods to study local cerebral perfusion have been proposed, offering several substantial advantages over nuclear medicine techniques, including noninvasiveness, no radiation exposure, easier accessibility, and higher spatial resolution [33] [34] . Among these innovative techniques, Arterial Spin Labeling (ASL) MRI has been applied to noninvasively study and quantify perfusion changes related to the epileptic focus. ASL provides a quantitative measurement of regional cerebral blood flow (CBF) without the need for contrast Patient-Specific CBF Alterations in Epilepsy PLOS ONE |
doi:10.1371/journal.pone.0123975 pmid:25946055 pmcid:PMC4422723 fatcat:3mm7g6wmvjbwdclcq7yblsebdm

Microstructural Diffusion Changes are Independent of Macrostructural Volume Loss in Moderate to Severe Alzheimer's Disease

Elisa Canu, Donald G. McLaren, Michele E. Fitzgerald, Barbara B. Bendlin, Giada Zoccatelli, Franco Alessandrini, Francesca B. Pizzini, Giuseppe K. Ricciardi, Alberto Beltramello, Sterling C. Johnson, Giovanni B. Frisoni
2010 Journal of Alzheimer's Disease  
Although it is established that Alzheimer's disease (AD) leads to cerebral macrostructural atrophy, microstructural diffusion changes have also been observed, but it is not yet known whether these changes offer unique information about the disease pathology. Thus, a multimodal imaging study was conducted to determine the independent contribution of each modality in moderate to severe AD. 17 patients with moderate-severe AD and 13 healthy volunteers underwent diffusion-weighted and T1-weighted
more » ... scanning. Images were processed to obtain measures of macrostructural atrophy (GM and WM volumes) and microstructural damage (fractional anisotropy and mean diffusivity). Microstructural diffusion changes independent of macrostructural loss were investigated using an ANCOVA where macrostructural maps were used as voxel-wise covariates. The reverse ANCOVA model was also assessed, where macrostructural loss was the dependent variable and microstructural DTI maps were the imaging covariates. Diffusion differences between patients and controls were observed after controlling for volumetric differences in medial temporal, retrosplenial regions, anterior commissure, corona radiata, internal capsule, thalamus, corticopontine tracts, cerebral peduncle, striatum and precentral gyrus. Independent volumetric differences were observed in the entorhinal cortex, inferior temporal lobe, posterior cingulate cortex, splenium and cerebellum. While it is well known that AD is associated with pronounced volumetric change, this study suggests that measures of microstructure provide unique information not obtainable with volumetric mapping in regions known to be pivotal in AD and in those thought to be spared. As such this work provides great understanding of the topography of pathological changes in AD that can be captured with imaging.
doi:10.3233/jad-2010-1295 pmid:20157252 pmcid:PMC2889147 fatcat:uiwkexllmve5znhhuvrtaasgjq

Mapping the Structural Brain Changes in Alzheimer's Disease: The Independent Contribution of Two Imaging Modalities

Elisa Canu, Donald G. McLaren, Michele E. Fitzgerald, Barbara B. Bendlin, Giada Zoccatelli, Franco Alessandrini, Francesca B. Pizzini, Giuseppe K. Ricciardi, Alberto Beltramello, Sterling C. Johnson, Giovanni B. Frisoni, J. Wesson Ashford (+7 others)
2011 Journal of Alzheimer's Disease  
The macrostructural atrophy of Alzheimer's disease (AD) has been fully described. Current literature reports that also microstructural alterations occur in AD since the early stages. However, whether the microstructural changes offer unique information independent from macrostructural atrophy is unclear. Aim of this study is to define the independent contribution of macrostructural atrophy and microstructural alterations on AD pathology. The study involved 17 moderate to severe AD patients and
more » ... 3 healthy controls. All participants underwent conventional and non conventional MRI (respectively, diffusion-weighted and T1weighted MR scanning). We processed the images in order to obtain gray and white matter volumes to assess macrostructural atrophy, and fractional anisotropy and mean diffusivity to assess the microstructural damage. Analyses of covariance between patients and controls were performed to investigate microstructural tissue damage independent of macrostructural tissue loss, and viceversa, voxel by voxel. We observed microstructural differences, independent of macrostructural atrophy, between patients and controls in temporal and retrosplenial regions, as well as in thalamus, corticopontine tracts, striatum and precentral gyrus. Volumetric differences, independent of microstructural alterations, were observed mainly in the entorhinal cortex, posterior cingulum, and splenium. Measures of microstructural damage provide unique information not obtainable with volumetric mapping in regions known to be pivotal in AD as well as in others thought to be spared. This work
doi:10.3233/jad-2011-0040 pmid:21971466 pmcid:PMC3267543 fatcat:qz3zwk7k4jha5n5uh4xe76kvne
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