Yuri Errante

Gadodiamide and Dentate Nucleus T1 Hyperintensity in Patients With Meningioma Evaluated by Multiple Follow-Up Contrast-Enhanced Magnetic Resonance Examinations With No Systemic Interval Therapy.

The dentate nucleus of the cerebellum may appear as hyperintense on unenhanced T1 magnetic resonance images (MRIs) of the brain. Recently, T1 signal hyperintensity has received attention owing to data on the association of this finding with the history of multiple injections of gadolinium-based contrast agents, specifically gadodiamide, in patients with multiple sclerosis and brain metastases. We conducted a retrospective study on patients with a meningioma who had routinely undergone follow-up enhanced MRI scans with gadodiamide. Across a time interval of 18 months (from January 2013 to July 2014), we identified 102 consecutive patients eligible for this study. A significant increase in T1 hyperintensity of the dentate nuclei of the cerebellum on nonenhanced scans was observed between the first and the last MRI in the group of patients with a history of at least 6 enhanced MRI scans (P < 0.01), whereas no differences were observed in the group with 1 to 5 enhanced MRI scans (P = 0.74). Further research is necessary to shed light on the mechanism of the T1 hyperintensity as well as on the histological and microstructural appearance of the dentate nucleus after multiple intravenous injections of gadodiamide. The finding raises the question of substantial dechelation of this agent in patients with normal renal function.

Diffusion-weighted lesions after carotid artery stenting are associated with cognitive impairment.

The effect of carotid artery stenting (CAS) on cognitive function is still debated. Cerebral microembolism, detectable by post-procedural diffusion-weighted imaging (DWI) lesions, has been suggested to predispose to cognitive decline. Our study aimed at evaluating the effect of CAS on cognitive profile focusing on the potential role of cerebral microembolic lesions, taking into consideration the impact of factors potentially influencing cognitive status (demographic features, vascular risk profile, neuropsychological evaluation at baseline and magnetic resonance (MR) markers of brain structural damage). Thirty-seven patients with severe carotid artery stenosis were enrolled. Neurological assessment, neuropsychological evaluation and brain MR were performed the day before CAS (E0). Brain MR with DWI was repeated the day after CAS (E1), while neuropsychological evaluation was done after a 14-month median period (E2). Volumes of both white matter hyperintensities and whole brain were estimated at E0 on axial MR FLAIR and T1w-SE sequences, respectively. Unadjusted ANOVA analysis showed a significant CAS*DWI interaction for MMSE (F=7.154(32), p=.012). After adjusting for factors potentially influencing cognitive status CAS*DWI interaction was confirmed for MMSE (F=7.092(13), p=.020). Patients with DWI lesions showed a mean E2-E0 MMSE reduction of -3.1, while group without DWI lesions showed a mean E2-E0 MMSE of +1.1. Our study showed that peri-procedural brain microembolic load impacts negatively on cognitive functions, independently from the influence of patients-related variables.

Regional MRI Diffusion, White-Matter Hyperintensities, and Cognitive Function in Alzheimer's Disease and Vascular Dementia

Background and Purpose An increase in brain water diffusivity as measured using magnetic resonance imaging (MRI) has been recently reported in normal-appearing white matter (NAWM) in patients affected by cognitive impairment. However, it remains to be clarified if this reflects an overt neuronal tissue disruption that leads to degenerative or microvascular lesions. This question was addressed by comparing the regional MRI apparent diffusion coefficients (ADCs) of NAWM in patients affected by Alzheimers disease (AD) or vascular dementia (VaD). The relationships of ADCs with the white-matter hyperintensity (WMH) burden, carotid atherosclerosis, and cognitive performance were also investigated. Methods Forty-nine AD and 31 VaD patients underwent brain MRI to assess the WMH volume and regional NAWM ADCs, neuropsychological evaluations, and carotid ultrasound to assess the plaque severity and intima-media thickness (IMT). Results Regional ADCs in NAWM did not differ between VaD and AD patients, while the WMH volume was greater in VaD than in AD patients. The ADC in the anterior corpus callosum was related to the WMH volume, while a greater carotid IMT was positively correlated with the temporal ADC and WMH volume. The memory performance was worse in patients with higher temporal ADCs. Constructional praxis scores were related to ADCs in the frontal, and occipital lobes, in the anterior and posterior corpus callosum as well as to the WMH volume. Abstract reasoning was related to frontal, parietal, and temporal ADCs. Conclusions Our data show that higher regional ADCs in NAWM are associated with microcirculatory impairment, as depicted by the WMH volume. Moreover, regional ADCs in NAWM are differently associated with the neuropsychological performances in memory, constructional praxia, and abstract reasoning domains.

MR differential diagnosis of acute deep grey matter pathology in paediatric patients

A high metabolic demand, rich vascularization and high concentrations of ionic elements leading to the generation of oxygen free radicals, give to the deep grey matter (DGM) nuclei specific susceptibility to both acute and chronic insults, especially in paediatric patients. Reaching a diagnosis in the early stages of acute diseases in many patients is crucial for instigating prompt specific therapy leading to a favourable outcome. On the basis of a review of a 10-year in-house database and a review of the literature on CNS pathology involving the DGM nuclei in paediatric patients, we summarize the MR findings and clinical clues that may help the radiologist in the difficult differential diagnosis process. The terms “acute” and “chronic” refer to the clinical onset of the disease. MR imaging allows the detection of an injury, determination of its precise anatomical location and characterization of the signal changes. This, combined with a knowledge of specific MRI patterns, may be a roadmap to a definite diagnosis. Clinical history, physical and laboratory findings, timing of the MR examination and advanced MR imaging techniques (diffusion-weighted imaging and 1H-MR spectroscopy), are crucial in some patients.

Magnetic resonance imaging differential diagnosis of brainstem lesions in children

Differential diagnosis of brainstem lesions, either isolated or in association with cerebellar and supra-tentorial lesions, can be challenging. Knowledge of the structural organization is crucial for the differential diagnosis and establishment of prognosis of pathologies with involvement of the brainstem. Familiarity with the location of the lesions in the brainstem is essential, especially in the pediatric population. Magnetic resonance imaging (MRI) is the most sensitive and specific imaging technique for diagnosing disorders of the posterior fossa and, particularly, the brainstem. High magnetic static field MRI allows detailed visualization of the morphology, signal intensity and metabolic content of the brainstem nuclei, together with visualization of the normal development and myelination. In this pictorial essay we review the brainstem pathology in pediatric patients and consider the MR imaging patterns that may help the radiologist to differentiate among vascular, toxico-metabolic, infective-inflammatory, degenerative and neoplastic processes. Helpful MR tips can guide the differential diagnosis: These include the location and morphology of lesions, the brainstem vascularization territories, gray and white matter distribution and tissue selective vulnerability.

Increased alpha band functional connectivity following the quadrato motor training: A longitudinal study

Quadrato Motor Training (QMT) is a new training paradigm, which was found to increase cognitive flexibility, creativity and spatial cognition. In addition, QMT was reported to enhance inter- and intra-hemispheric alpha coherence as well as Fractional Anisotropy (FA) in a number of white matter pathways including corpus callosum. Taken together, these results seem to suggest that electrophysiological and structural changes induced by QMT may be due to an enhanced interplay and communication of the different brain areas within and between the right and the left hemisphere. In order to test this hypothesis using the exact low-resolution brain electromagnetic tomography (eLORETA), we estimated the current neural density and lagged linear connectivity (LLC) of the alpha band in the resting state electroencephalography (rsEEG) recorded with open (OE) and closed eyes (CE) at three different time points, following 6 and 12 weeks of daily QMT. Significant changes were observed for the functional connectivity. In particular, we found that limbic and fronto-temporal alpha connectivity in the OE condition increased after 6 weeks, while it enhanced at the CE condition in occipital network following 12-weeks of daily training. These findings seem to show that the QMT may have dissociable long-term effects on the functional connectivity depending on the different ways of recording rsEEG. OE recording pointed out a faster onset of Linear Lag Connectivity modulations that tend to decay as quickly, while CE recording showed sensible effect only after the complete 3-months training.

Bilateral remote cerebellar haemorrhage after spinal surgery: a case study and review of the literature.

Abstract Background: Remote cerebellar haemorrhage is a rare and unpredictable complication after intracranial and spinal surgery, although less frequently found in the latter. The physiopathology of this phenomenon has not been definitely explained. Objectives: To describe and discuss the potential implications and pathomechanism of a bilateral remote cerebellar haemorrhage case after spinal surgery and review the literature related to this rare phenomenon. Case report: A 75 year-old man developed bilateral remote cerebellar haemorrhage after a lumbar laminectomy. Brain CT and MRI examinations showed chronic bilateral remote cerebellar haemorrhage, right haemoventricle and bilateral supratentorial subarachnoid haemorrhage. Subsequently, the patient underwent rehabilitation therapy with improvement of symptoms. Conclusion: When large cerebrospinal fluid loss is observed during spinal surgery, brain imaging study should be carried out. The pathogenetic hypothesis of microcirculation vessels tearing, the role of previous spinal surgery and of cerebellar atrophy should be considered and validated with further investigation.

Differential effect of zoledronic acid on normal trabecular and cortical bone density in oncologic patients with bone metastases

Purpose To evaluate bone density changes at the level of normal bone and bone metastases after zoledronic acid (ZA) treatment in oncologic patients. Materials and methods We retrospectively evaluated 72 consecutive adult patients with histologically confirmed solid tumors with at least 1 newly diagnosed bone metastatic lesion. Bone metastases were diagnosed by bone scans and confirmed with computed tomography (CT). Patients received intravenous ZA, 4 mg, by 15-min infusion every 28 day through a peripheral or a central venous access and were monitored for at least 3 months and a maximum of 24 months. Bone density was determined at the level of bone metastases and at the level of normal trabecular and cortical bone using a ROI-based approach. Results A significant increase was demonstrated at the level of normal trabecular bone of the calvarium and the femoral neck. No significant increase of density was observed at the level of the normal cortical bone. Bone metastases showed a significant increase in CT density as compared to baseline up to 24 months after zoledronic acid. Conclusion We have found that long term treatment with ZA increases trabecular bone density in oncologic patients whereas normal cortical bone changes are not detectable.

Central nervous system tuberculosis in non-HIV-positive children: a single-center, 6 year experience

PurposeThe aim of this paper is to describe the imaging features of central nervous system (CNS) tuberculosis on computed tomography (CT) and magnetic resonance imaging (MRI) studies in non-HIV-positive children.Materials and methodsA retrospective descriptive evaluation was conducted on imaging studies obtained from ten children admitted to our hospital over a 6-year period who fulfilled criteria for a diagnosis of CNS tuberculosis. Data were collected with regard to patients’ clinical, laboratory and demographic characteristics, as well as results of radiological investigation.ResultsWe studied ten children, of whom five were boys and five were girls and whose mean age was 4 (range 7 months to16) years. Neuroradiological findings on the first imaging study were basal meningeal enhancement (100%), hydrocephalus (70%), infarcts (90%), tuberculomas (40%) and cranial nerve involvement (20%). Follow-up studies revealed basal meningeal enhancement, hydrocephalus, and infarcts in all patients, tuberculomas in 70% and cranial nerve involvement in 50%. Only one patient showed a pattern of miliary tuberculosis.ConclusionsCNS tuberculosis is still an important cause of childhood morbidity and mortality even in nonimmunosuppressed children. Because prompt diagnosis results in earlier treatment, it is crucial to be aware of tuberculous meningitis and its complications at imaging, especially because of the impact on patients’ prognosis.RiassuntoObiettivoScopo di questo studio è descrivere le caratteristiche della tubercolosi del sistema nervoso centrale alla tomografia computerizzata e alla risonanza magnetica, in un gruppo di bambini non positivi al virus dell’immunodeficienza umana acquisita (HIV).Materiali e metodiAbbiamo condotto una indagine retrospettiva descrittiva su 10 bambini con diagnosi di tubercolosi del sistema nervoso centrale, ricoverati nel nostro ospedale in un periodo di 6 anni. I dati dei pazienti riguardavano gli aspetti clinici, laboratoristici, demografici e neuroradiologici.RisultatiSono stati ammessi nello studio 10 pazienti, 5 maschi e 5 femmine. L’età media dei pazienti era di 4 anni (tra 7 mesi e 16 anni). I reperti neuroradiologici rilevati all’indagine iniziale sono stati impregnazione delle meningi della base cranica (100%), idrocefalo (70%), lesioni infartuali (90%), tubercolomi (40%) e interessamento dei nervi cranici (20%). Nel controllo successivo tutti i pazienti presentavano impregnazione delle meningi della base cranica, idrocefalo e infarti, il 70% presentava tubercolomi e il 50% interessamento dei nervi cranici. Solo in un paziente è stata evidenziata una forma miliare.ConclusioniLa infezione tubercolare del sistema nervoso centrale è ancora un’importante causa di morbilità e mortalità in bambini non immunodepressi. Poiché l’inizio precoce della terapia determina una prognosi migliore è importante effettuare una diagnosi neuroradiologica tempestiva.

White Matter Microstructural Changes Following Quadrato Motor Training: A Longitudinal Study

Diffusion tensor imaging (DTI) is an important way to characterize white matter (WM) microstructural changes. While several cross-sectional DTI studies investigated possible links between mindfulness practices and WM, only few longitudinal investigations focused on the effects of these practices on WM architecture, behavioral change, and the relationship between them. To this aim, in the current study, we chose to conduct an unbiased tract-based spatial statistics (TBSS) analysis (n = 35 healthy participants) to identify longitudinal changes in WM diffusion parameters following 6 and 12 weeks of daily Quadrato Motor Training (QMT), a whole-body mindful movement practice aimed at improving well-being by enhancing attention, coordination, and creativity. We also investigated the possible relationship between training-induced WM changes and concomitant changes in creativity, self-efficacy, and motivation. Our results indicate that following 6 weeks of daily QMT, there was a bilateral increase of fractional anisotropy (FA) in tracts related to sensorimotor and cognitive functions, including the corticospinal tracts, anterior thalamic radiations, and uncinate fasciculi, as well as in the left inferior fronto-occipital, superior and inferior longitudinal fasciculi. Interestingly, significant FA increments were still present after 12 weeks of QMT in most of the above WM tracts, but only in the left hemisphere. FA increase was accompanied by a significant decrease of radial diffusivity (RD), supporting the leading role of myelination processes in training-related FA changes. Finally, significant correlations were found between training-induced diffusion changes and increased self-efficacy as well as creativity. Together, these findings suggest that QMT can improve WM integrity and support the existence of possible relationships between training-related WM microstructural changes and behavioral change.