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Magnetic resonance imaging-positive temporal lobe atrophy with temporo-polar grey/white matter abnormalities (usually called 'blurring') has been frequently reported in patients with temporal lobe epilepsy associated with hippocampal sclerosis. The poor distinction of grey and white matter has been attributed to various causes, including developmental cortical abnormalities, gliosis, myelin alterations, a non-specific increase in temporal lobe water content and metabolic/perfusion alterations. However, there is still no consensus regarding the genesis of these abnormalities and no histopathological proof for a structural nature of magnetic resonance imaging changes. The aim of this study was to investigate the pathological substrate of temporo-polar blurring using different methodological approaches and evaluate the possible clinical significance of the abnormalities. The study involved 32 consecutive patients with medically intractable temporal lobe epilepsy and hippocampal sclerosis who underwent surgery after a comprehensive electroclinical and imaging evaluation. They were divided into two groups on the basis of the presence/absence of temporo-polar blurring. Surgical specimens were examined neuropathologically, and selected samples from both groups underwent high-field 7 T magnetic resonance imaging and ultrastructural studies. At the clinical level, the two groups were significantly different in terms of age at epilepsy onset (earlier in the patients with blurring) and epilepsy duration (longer in the patients with blurring). Blurring was also associated with lower neuropsychological test scores, with a significant relationship to abstract reasoning. On 7 T magnetic resonance image examination, the borders between the grey and white matter were clear in all of the samples, but only those with blurring showed a dishomogeneous signal in the white matter, with patchy areas of hyperintensity mainly in the depth of the white matter. Sections from the patients with blurring that were processed for myelin staining revealed dishomogeneous staining of the white matter, which was confirmed by analyses of the corresponding semi-thin sections. Ultrastructural examinations revealed the presence of axonal degeneration and a significant reduction in the number of axons in the patients with blurring; there were no vascular alterations in either group. These data obtained using different methodological approaches provide robust evidence that temporo-polar blurring is caused by the degeneration of fibre bundles and suggest slowly evolving chronic degeneration with the redistribution of the remaining fibres. The article also discusses the correlations between the morphological findings and clinical data.

We applied a data‐driven analysis based on self‐organizing group independent component analysis (sogICA) to fMRI data from a three‐stimulus visual oddball task. SogICA is particularly suited to the investigation of the underlying functional connectivity and does not rely on a predefined model of the experiment, which overcomes some of the limitations of hypothesis‐driven analysis. Unlike most previous applications of ICA in functional imaging, our approach allows the analysis of the data at the group level, which is of particular interest in high order cognitive studies. SogICA is based on the hierarchical clustering of spatially similar independent components, derived from single subject decompositions. We identified four main clusters of components, centered on the posterior cingulate, bilateral insula, bilateral prefrontal cortex, and right posterior parietal and prefrontal cortex, consistently across all participants. Post hoc comparison of time courses revealed that insula, prefrontal cortex and right fronto‐parietal components showed higher activity for targets than for distractors. Activation for distractors was higher in the posterior cingulate cortex, where deactivation was observed for targets. While our results conform to previous neuroimaging studies, they also complement conventional results by showing functional connectivity networks with unique contributions to the task that were consistent across subjects. SogICA can thus be used to probe functional networks of active cognitive tasks at the group‐level and can provide additional insights to generate new hypotheses for further study. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.

In patients with progressive supranuclear palsy (PSP), previous reports have shown a severe white matter (WM) damage involving supra and infratentorial regions including cerebellum. In the present study, we investigated potential correlations between WM integrity loss and clinical-cognitive features of patients with PSP. By using magnetic resonance imaging and diffusion tensor imaging with tract based spatial statistic analysis, we analyzed WM volume in 18 patients with PSP and 18 healthy controls (HCs). All patients and HCs underwent a detailed clinical and neuropsychological evaluation. Relative to HCs, patients with PSP showed WM changes encompassing supra and infratentorial areas such as corpus callosum, fornix, midbrain, inferior fronto-occipital fasciculus, anterior thalamic radiation, superior cerebellar peduncle, superior longitudinal fasciculus, uncinate fasciculus, cingulate gyrus, and cortico-spinal tract bilaterally. Among different correlations between motor-cognitive features and WM structural abnormalities, we detected a significant association between fronto-cerebellar WM loss and executive cognitive impairment in patients with PSP. Our findings, therefore, corroborate the hypothesis that cognitive impairment in PSP may result from both "intrinsic" and "extrinsic" frontal lobe dysfunction, likely related to cerebellar disconnection.

Paediatric urology often presents challenging scenarios. Magnetic resonance urography (MRU) and laparoscopy are increasingly used. We retrospectively studied children affected by a disease of the upper urinary tract who after MRU were elected for laparoscopic treatment. This pictorial essay draws on our experience; it illustrates some specific MRU findings and highlights the usefulness of MRU for the diagnosis of upper urinary tract pathology in children. It also offers some examples of the potential additional diagnostic information provided by laparoscopy as well as its therapeutic role.

ObjectiveTo improve the characterization of asymptomatic subjects with brain magnetic resonance imaging (MRI) abnormalities highly suggestive of multiple sclerosis (MS), a condition named as "radiologically isolated syndrome" (RIS).MethodsQuantitative MRI metrics such as brain volumes and magnetization transfer (MT) were assessed in 19 subjects previously classified as RIS, 20 demographically-matched relapsing-remitting MS (RRMS) patients and 20 healthy controls (HC). Specific measures were: white matter (WM) lesion volumes (LV), total and regional brain volumes, and MT ratio (MTr) in lesions, normal-appearing WM (NAWM) and cortex.ResultsLV was similar in RIS and RRMS, without differences in distribution and frequency at lesion mapping. Brain volumes were similarly lower in RRMS and RIS than in HC (pConclusionsMacroscopic brain damage was similar in RIS and RRMS. However, the subtle tissue damage detected by MTr was milder in RIS than in RRMS in clinically relevant brain regions, suggesting an explanation for the lack of clinical manifestations of subjects with RIS. This new approach could be useful for narrowing down the RIS individuals with a high risk of progression to MS.

Ultrasound (US) and MR imaging have been shown able to detect in-depth features of brachial plexus anatomy and to localize pathological lesions in disorders where electrophysiology and physical findings are nonspecific or nonlocalizing. High-end gradient technology, phased array coils, and selection of an appropriate protocol of pulse sequences are the main requirements to evaluate the brachial plexus nerves with MR imaging and to distinguish between intrinsic and extrinsic pathological changes. A careful scanning technique based on anatomical landmarks is required to image the brachial plexus nerves with US. In traumatic injuries, MR imaging and myelographic techniques can exclude nerve lesions at the level of neural foramina and at intradural location. Outside the spinal canal, US is an excellent alternative to MR imaging to determine the presence of a lesion, to establish the site and the level of nerve involvement, as well as to confirm or exclude major nerve injuries. In addition to brachial plexus injuries, MR imaging and US can be contributory in a variety of nontraumatic brachial plexopathies of a compressive, neoplastic, and inflammatory nature. In the thoracic outlet syndrome, imaging performed in association with postural maneuvers can help diagnose dynamic compressions. MR imaging and US are also effective to recognize neuropathies about the shoulder girdle involving the suprascapular, axillary, long thoracic, and spinal accessory nerves that may mimic brachial plexopathy. In this article, the clinical entities just listed are discussed independently, providing an overview of the current status of knowledge regarding imaging assessment.

Pre‐attentive registration of aberrations in predictable sound patterns is attributed to the temporal cortex. However, electrophysiology suggests that frontal areas become more important when deviance complexity increases. To play an instrument in an ensemble, professional musicians have to rely on the ability to detect even slight deviances from expected musical patterns and therefore have highly trained aural skills. Here, we aimed to identify the neural correlates of experience‐driven plasticity related to the processing of complex sound features. We used functional magnetic resonance imaging in combination with an event‐related oddball paradigm and compared brain activity in professional musicians and non‐musicians during pre‐attentive processing of melodic contour variations. The melodic pattern consisted of a sequence of five tones each lasting 50 ms interrupted by silent interstimulus intervals of 50 ms. Compared to non‐musicians, the professional musicians showed enhanced activity in the left middle and superior temporal gyri, the left inferior frontal gyrus and in the right ventromedial prefrontal cortex in response to pattern deviation. This differential brain activity pattern was correlated with behaviorally tested musical aptitude. Our results thus support an experience‐related role of the left temporal cortex in fast melodic contour processing and suggest involvement of the prefrontal cortex. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.

Functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) represent brain activity in terms of a reliable anatomical localization and a detailed temporal evolution of neural signals. Simultaneous EEG-fMRI recordings offer the possibility to greatly enrich the significance and the interpretation of the single modality results because the same neural processes are observed from the same brain at the same time. Nonetheless, the different physical nature of the measured signals by the two techniques renders the coupling not always straightforward, especially in cognitive experiments where spatially localized and distributed effects coexist and evolve temporally at different temporal scales. The purpose of this article is to illustrate the combination of simultaneously recorded EEG and fMRI signals exploiting the principles of EEG distributed source modeling. We define a common source space for fMRI and EEG signal projection and gather a conceptually unique framework for the spatial and temporal comparative analysis. We illustrate this framework in a graded-load working-memory simultaneous EEG-fMRI experiment based on the n-back task where sustained load-dependent changes in the blood-oxygenation-level-dependent (BOLD) signals during continuous item memorization co-occur with parametric changes in the EEG theta power induced at each single item. In line with previous studies, we demonstrate on two single-subject cases how the presented approach is capable of colocalizing in midline frontal regions two phenomena simultaneously observed at different temporal scales, such as the sustained negative changes in BOLD activity and the parametric EEG theta synchronization. We discuss the presented approach in relation to modeling and interpretation issues typically arising in simultaneous EEG-fMRI studies.

An overview is given of magnetic resonance (MR) techniques sensitized to diffusion, flow, magnetization transfer effect, and local field inhomogeneities induced by physiological changes, that can be viewed, in the clinical practice, as advanced because of their challenging implementation and interpretation. These techniques are known as diffusion-weighted, perfusion, magnetization transfer, functional MRI and MR spectroscopy. An important issue is that they can provide quantitative estimates of structural and functional characteristics that are below the voxel resolution. This review does not deal with the basic concepts of the MR physics and the description of the available acquisition and postprocessing methods, but hopefully provides an adequate background to readers and hence facilitate the understanding of the following clinical contributions.

This study aimed to determine whether white matter lesions, previously described as a frequent feature in myotonic dystrophy type 1 (DM1), aggregate within DM1 families or are sporadic findings, and to explore the relationship between these lesions and clinical or genetic features. Brain MRI of 60 DM1 patients belonging to 22 families were evaluated and white matter lesions were rated according to a semiquantitative method. Presence and extent of lobar, temporal or periventricular lesions showed a significant association with the family history of lesions and the disease duration, and no association with the CTG repeat size. Furthermore, parent-offspring and sibling pairs showed a significant positive concordance for lesion severity. White matter lesions demonstrate familial aggregation in DM1 and no relationship with CTG repeat length. These findings suggest that other genetic causes and/or unknown environmental factors influence the occurrence and severity of lesions in patients carrying the DM1 genetic defect.

We compared 3-Tesla (3-T) and 1.5-Tesla (1.5-T) cardiac magnetic resonance imaging (MRI) for the assessment of myocardial viability in nearly identical experimental conditions.Thirty-five patients (mean age 63+/-11; 94.2% men) submitted to primary coronary angioplasty underwent both 3-T and 1.5-T cardiac MRI, which was considered the gold standard. Comparison was performed on the basis of the same viability imaging protocol, which included resting cine-MR [balanced fast-field echo (B-FFE) sequence] followed by contrast-enhanced MR to evaluate perfusion and delayed enhancement (DE). We then performed functional index measurements and visual estimation of kinesis, perfusion and DE referring to a 5-point scale. Image quality was assessed on the basis of signal to noise ratio (SNR) and contrast to noise ratio (CNR).We found nonsignificant differences between the two scanners (P=NS) in measuring the functional and viability parameters. Myocardial SNR was significantly higher with 3-T MRI compared with 1.5-T MRI (61.3% gain). Even though a loss of CNR was recorded in B-FFE and in first-pass perfusion sequences (12.4% and 23.7%, respectively), on DE images, we quantified the increase of SNR and CNR of infarction of 387.8% and 330%, respectively.We found that 3-T MRI showed high concordance with 1.5-T MRI in the evaluation of functional and viability parameters and provided better evidence of damaged myocardium.

The aim of this paper is to illustrate the technical, methodological and diagnostic features of functional imaging (comprising spectroscopy, diffusion, perfusion and cortical activation techniques) and its principal neuroradiological applications on the basis of the experience gained by the authors in the 5 years since the installation of a high-field magnetic resonance (MR) magnet. These MR techniques are particularly effective at 3.0 Tesla (T) owing to their high signal, resolution and sensitivity, reduced scanning times and overall improved diagnostic ability. In particular, the high-field strength enhances spectroscopic analysis due to a greater signal-to-noise ratio (SNR) and improved spectral, space and time resolution, resulting in the ability to obtain high-resolution spectroscopic studies not only of the more common metabolites, but also--and especially--of those which, due to their smaller concentrations, are difficult to detect using 1.5-T systems. All of these advantages can be obtained with reduced acquisition times. In diffusion studies, the high-field strength results in greater SNR, because 3.0-T magnets enable increased spatial resolution, which enhances accuracy. They also allow exploration in greater detail of more complex phenomena (such as diffusion tensor and tractography), which are not clearly depicted on 1.5-T systems. The most common perfusion study (with intravenous injection of a contrast agent) benefits from the greater SNR and higher magnetic susceptibility by achieving dramatically improved signal changes, and thus greater reliability, using smaller doses of contrast agent. Functional MR imaging (fMRI) is without doubt the modality in which high-field strength has had the greatest impact. Images acquired with the blood-oxygen-level-dependent (BOLD) technique benefit from the greater SNR afforded by 3.0-T magnets and from their stronger magnetic susceptibility effects, providing higher signal and spatial resolution. This enhances reliability of the localisation of brain functions, making it possible to map additional areas, even in the millimetre and submillimetre scale. The data presented and results obtained to date show that 3.0-T morphofunctional imaging can become the standard for high-resolution investigation of brain disease.

In the last few years, Functional Magnetic Resonance Imaging (fMRI) has been widely accepted as an effective tool for mapping brain activities in both the neurosensorial and the cognitive field. The present work aims to assess the possibility of using fMRI methods to perform a non-invasive evaluation of the human auditory function. To this end the cortical response to different non speech stimuli (pure tones, pulsed tones) was examined for ten subjects with no audiological impairment. Our findings point out some remarkable differences in both the spatial and the temporal features of the primary auditory cortex response to pulsed tones and to pure tones.

To assess whether brain tissue loss occurs after profound and sustained suppression of magnetic resonance imaging (MRI) enhancement, we measured brain volume changes from 10 patients with rapidly evolving secondary progressive multiple sclerosis (MS) treated with autologous haematopoietic stem cell transplantation and followed up for 24 months. An average yearly decrease of brain volume of about 1.9% was observed despite only five enhancing lesions seen on triple dose follow up scans of two patients. This indicates that, in MS, progressive loss of tissue can occur independently of concomitant MRI-visible inflammation.

The "default-mode" network is an ensemble of cortical regions that are typically deactivated during demanding cognitive tasks in functional magnetic resonance imaging (fMRI) studies. Using functional connectivity analysis, this network can be studied as a "stand-alone" brain system whose functional role is supposed to consist in the dynamic control of intrinsic processing activities like attention focusing and task-unrelated thought generation and suppression. Independent component analysis (ICA) is the method of choice for generating a statistical image of the "default-mode" network (DMN) using a task- and seed-independent distributed model of fMRI functional connectivity without prior specification of node region extent and timing of neural activation. We used a standard graded working-memory task (n-back) to induce fMRI changes in the default-mode regions and ICA to evaluate to DMN functional connectivity in nineteen healthy volunteers. Based on the known spatial variability of the ICA-DMN maps with the task difficulty levels, we hypothesized the ICA-DMN may also correlate with the subject performances. We confirmed that the relative extent of the anterior and posterior midline spots within the DMN were oppositely (resp. positively in the anterior and negatively in the posterior cingulate cortex) correlated with the level of task difficulty and found out that the spatial distribution of DMN also correlates with the individual task performances. We conclude that the working-memory function is related to a spatial re-configuration of the DMN functional connectivity, and that the relative involvement of the cingulate regions within the DMN might function as a novel predictor of the working-memory efficiency.