Inefficient white matter activity in Schizophrenia evoked during intra and inter-hemispheric communication.

Intensive cognitive tasks induce inefficient regional and network responses in schizophrenia (SCZ). fMRI-based studies have naturally focused on gray matter, but appropriately titrated visuo-motor integration tasks reliably activate inter- and intra-hemispheric white matter pathways. Such tasks can assess network inefficiency without demanding intensive cognitive effort. Here, we provide the first application of this framework to the study of white matter functional responses in SCZ. Event-related fMRI data were acquired from 28 patients (nine females, mean age 43.3, ±11.7) and 28 age- and gender-comparable controls (nine females, mean age 42.1 ± 10.1), using the Poffenberger paradigm, a rapid visual detection task used to induce intra- (ipsi-lateral visual and motor cortex) or inter-hemispheric (contra-lateral visual and motor cortex) transfer. fMRI data were pre- and post-processed to reliably isolate activations in white matter, using probabilistic tractography-based white matter tracts. For intra- and inter-hemispheric transfer conditions, SCZ evinced hyper-activations in longitudinal and transverse white matter tracts, with hyper-activation in sub-regions of the corpus callosum primarily observed during inter-hemispheric transfer. Evidence for the functional inefficiency of white matter was observed in conjunction with small (~50 ms) but significant increases in response times. Functional inefficiencies in SCZ are (1) observable in white matter, with the degree of inefficiency contextually related to task-conditions, and (2) are evoked by simple detection tasks without intense cognitive processing. These cumulative results while expanding our understanding of this dys-connection syndrome, also extend the search of biomarkers beyond the traditional realm of fMRI studies of gray matter.

Two years' effect of dimethyl fumarate on focal and diffuse gray matter pathology in multiple sclerosis.

BACKGROUND: Data on the effect of dimethyl fumarate (DMF) on focal and diffuse gray matter (GM) damage, a relevant pathological substrate of multiple sclerosis (MS)-related disability are lacking. OBJECTIVE: To evaluate the DMF effect on cortical lesions (CLs) accumulation and global and regional GM atrophy in subjects with relapsing-remitting MS. METHODS: A total of 148 patients (mean age 38.1 ± 9.7 years) treated with DMF ended a 2-year longitudinal study. All underwent regular Expanded Disability Status Scale (EDSS assessment), and at least two 3T-magnetic resonance imaging (MRI) at 3 and 24 months after DMF initiation. CLs and changes in global and regional atrophy of several brain regions were compared with 47 untreated age and sex-matched patients. RESULTS: DMF-treated patients showed lower CLs accumulation (median 0[0-3] vs 2[0-7], p < 0.001) with respect to controls. Global cortical thickness (p < 0.001) and regional thickness and volume were lower in treated group (cerebellum, hippocampus, caudate, and putamen: p < 0.001; thalamus p = 0.03). Lower relapse rate (14% vs 40%, p < 0.001), EDSS change (0.2 ± 0.4 vs 0.4 ± 0.9, p < 0.001), and new WM lesions (median 0[0-5] vs 2[0-6], p < 0.001) were reported. No severe adverse drug reactions occurred. CONCLUSIONS: Beyond the well-known effect on disease activity, these results provide evidence of the effect of DMF through reduced progression of focal and diffuse GM damage.

CSF TNF and osteopontin levels correlate with the response to dimethyl fumarate in early multiple sclerosis.

Background: Disease activity in the first years after a diagnosis of relapsing-remitting multiple sclerosis (RRMS) is a negative prognostic factor for long-term disability. Markers of both clinical and radiological responses to disease-modifying therapies (DMTs) are advocated. Objective: The objective of this study is to estimate the value of cerebrospinal fluid (CSF) inflammatory markers at the time of diagnosis in predicting the disease activity in treatment-naïve multiple sclerosis (MS) patients exposed to dimethyl fumarate (DMF). Methods: In total, 48 RRMS patients (31 females/17 males) treated with DMF after the diagnosis were included in this 2-year longitudinal study. All patients underwent a CSF examination, regular clinical and 3T magnetic resonance imaging (MRI) scans that included the assessment of white matter (WM) lesions, cortical lesions (CLs) and global cortical thickness. CSF levels of 10 pro-inflammatory markers - CXCL13 [chemokine (C-X-C motif) ligand 13 or B lymphocyte chemoattractant], CXCL12 (stromal cell-derived factor or C-X-C motif chemokine 12), tumour necrosis factor (TNF), APRIL (a proliferation-inducing ligand, or tumour necrosis factor ligand superfamily member 13), LIGHT (tumour necrosis factor ligand superfamily member 14 or tumour necrosis factor superfamily member 14), interferon (IFN) gamma, interleukin 12 (IL-12), osteopontin, sCD163 [soluble-CD163 (cluster of differentiation 163)] and Chitinase3-like1 - were assessed using immune-assay multiplex techniques. The combined three-domain status of 'no evidence of disease activity' (NEDA-3) was defined by no relapses, no disability worsening and no MRI activity, including CLs. Results: Twenty patients (42%) reached the NEDA-3 status; patients with disease activity showed higher CSF TNF (p = 0.009), osteopontin (p = 0.005), CXCL12 (p = 0.037), CXCL13 (p = 0.040) and IFN gamma levels (p = 0.019) compared with NEDA-3 patients. After applying a random forest approach, TNF and osteopontin revealed the most important variables associated with the NEDA-3 status. Six molecules that emerged at the random forest approach were added in a multivariate regression model with demographic, clinical and MRI measures of WM and grey matter damage as independent variables. TNF levels confirmed to be associated with the absence of disease activity: odds ratio (OR) = 0.25, CI% = 0.04-0.77. Conclusion: CSF inflammatory markers may provide prognostic information in predicting disease activity in the first years after DMF initiation. CSF TNF levels are a possible candidate in predicting treatment response, in addition to clinical, demographic and MRI variables.

Diffuse gliomas in patients aged 55 years or over: A suggestion for IDH mutation testing.

Diffuse gliomas are defined on the isocitrate dehydrogenase (IDH) gene (IDH) mutational mutational status. The most frequent IDH mutation is IDH1 R132H, which is detectable by immunohistochemistry; other IDH mutations are rare (10%). IDH mutant gliomas have better prognosis. Further, IDH wild-type low-grade (II/III) gliomas have clinical behaviors similar to those of glioblastoma (GBM) and it was suggested that they are submitted to similar post-surgical treatment. The incidence of IDH mutant gliomas (2%) and that of GBMs with non-canonical IDH mutations (< 1%) are very low in patients ≥ 55 years. For this reason, it was suggested that immunohistochemistry against IDH1 R132H is sufficient to classify GBM as IDH wild-type in this age group. However, no indication was provided for IDH mutational testing in low-grade diffuse gliomas. To address this issue, 273 diffuse gliomas were tested for IDH1 R132H immunohistochemistry. 2/4 diffuse astrocytomas (DAs), 4/9 anaplastic astrocytomas (AAs), 2/256 GBMs, and 4/4 oligodendrogliomas had positive staining. No other IDH mutations were found in immuno-negative low-grade cases by DNA sequencing. To validate our findings, we considered 311 diffuse gliomas in patients ≥ 55 years in The Cancer Genome Atlas database. Fifty-five out of 311 gliomas had IDH R132H mutations (9/16 DAs; 8/48 AAs; 3/211 GBMs; 35/36 oligodendrogliomas), one DA, and one oligodendroglioma had other IDH mutations. IDH mutant gliomas had significantly higher frequency of O-6-methylguanine-DNA methyltransferase promoter methylation (P = 0.0008) and longer overall survival (P < 0.0001). In conclusion, low-grade gliomas are a minor part of gliomas (117/584) in patients ≥ 55 years, albeit they represent most IDH mutant gliomas in this age group (64/69 cases). IDH non-canonical mutations can be found in immunonegative low-grade gliomas (2/54). In view of its significance for prognosis and therapeutic management, our results suggest that IDH mutational status is assessed in all diffuse gliomas in patients ≥ 55 years by immunohistochemistry, followed by IDH sequencing in low-grade immunonegative cases.

Magnetic resonance diffusion-tensor imaging metrics in High Grade Gliomas: Correlation with IDH1 gene status in WHO 2016 era.

PURPOSE: 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). METHODS: 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. RESULTS: We observed a positive correlation with IDH1 status and RD and MD data. No correlation was demonstrated between IDH1 status and FA and AD. DISCUSSION: 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. CONCLUSIONS: 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.

The use of electrical source imaging in targeting lesional mesial temporal epilepsy for radiosurgical treatment.

Gamma knife radiosurgery (GK-RS) is a technique applied in selected cases of mesial-temporal epilepsy, although still limited to centres with adequate instrumentation and expertise. Here, we report a case of radio surgery targeted with the aid of electrical source imaging that localizes the cortical area generating the scalp epileptic discharges. The patient, a 39-year-old male, presented with a right mesio-temporal lesion; electrical source imaging localization partially overlapped with the lesional area but showed an important activation of the omolateral frontal area, concordant with the epileptic network. The patient underwent GK-RS, with good neurosurgical and clinical results. A radiosurgical ellipsoidal treatment volume area of 2 × 2 × 2 cm³, located over the right temporo-mesial region within a centre showing abnormal signal intensity, was considered. Seven months after treatment, the patient developed brain oedema that gradually resolved after one year. After three years of follow-up, the patient was seizure-free (Engel class I). Our very preliminary experience suggests that electrical source imaging appears to be a useful supporting tool for the definition of the radiosurgical treatment volume in selected patients with temporo-mesial lesional epilepsy.

Integration of functional neuroimaging in CyberKnife radiosurgery: feasibility and dosimetric results.

OBJECT: The integration of state-of-the-art neuroimaging into treatment planning may increase the therapeutic potential of stereotactic radiosurgery. Functional neuroimaging, including functional MRI, navigated brain stimulation, and diffusion tensor imaging-based tractography, may guide the orientation of radiation beams to decrease the dose to critical cortical and subcortical areas. The authors describe their method of integrating functional neuroimaging technology into radiosurgical treatment planning using the CyberKnife radiosurgery system. METHODS: The records of all patients who had undergone radiosurgery for brain lesions at the CyberKnife Center of the University of Messina, Italy, between July 2010 and July 2012 were analyzed. Among patients with brain lesions in critical areas, treatment planning with the integration of functional neuroimaging was performed in 25 patients. Morphological and functional imaging data sets were coregistered using the Multiplan dedicated treatment planning system. Treatment planning was initially based on morphological data; radiation dose distribution was then corrected in relation to the functionally relevant cortical and subcortical areas. The change in radiation dose distribution was then calculated. RESULTS: The data sets could be easily and reliably integrated into the Cyberknife treatment planning. Using an inverse planning algorithm, the authors achieved an average 17% reduction in the radiation dose to functional areas. Further gain in terms of dose sparing compromised other important treatment parameters, including target coverage, conformality index, and number of monitor units. No neurological deficit due to radiation was recorded at the short-term follow-up. CONCLUSIONS: Radiosurgery treatments rely on the quality of neuroimaging. The integration of functional data allows a reduction in radiation doses to functional organs at risk, including critical cortical areas, subcortical tracts, and vascular structures. The relative simplicity of integrating functional neuroimaging into radiosurgery warrants further research to implement, standardize, and identify the limits of this procedure.

Early MRI changes in glioblastoma in the period between surgery and adjuvant therapy.

To investigate the increase in MRI contrast enhancement (CE) occurring in glioblastoma during the period between surgery and initiation of chemo-radiotherapy, thirty-seven patients with newly diagnosed glioblastoma were analyzed by early post-operative magnetic resonance (EPMR) imaging within three days of surgery and by pre-adjuvant magnetic resonance (PAMR) examination before adjuvant therapy. Areas of new CE were investigated by use of EPMR diffusion-weighted imaging and PAMR perfusion imaging (by arterial spin-labeling). PAMR was acquired, on average, 29.9 days later than EPMR (range 20-37 days). During this period an increased area of CE was observed for 17/37 patients. For 3/17 patients these regions were confined to areas of reduced EPMR diffusion, suggesting postsurgical infarct. For the other 14/17 patients, these areas suggested progression. For 11/17 patients the co-occurrence of hyperperfusion in PAMR perfusion suggested progression. PAMR perfusion and EPMR diffusion did not give consistent results for 3/17 patients for whom small new areas of CE were observed, presumably because of the poor spatial resolution of perfusion imaging. Before initiation of adjuvant therapy, areas of new CE of resected glioblastomas are frequently observed. Most of these suggest tumor progression, according to EPMR diffusion and PAMR perfusion criteria.

Mapping the structural brain changes in Alzheimer's disease: the independent contribution of two imaging modalities.

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 13 healthy controls. All participants underwent conventional and non conventional MRI (respectively, T1-weighted and diffusion-weighted 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 vice versa, 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 expands the understanding of the topography of pathological changes in AD that can be captured with imaging techniques.

Microstructural diffusion changes are independent of macrostructural volume loss in moderate to severe 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 multi-modal imaging study was conducted to determine the independent contribution of each modality in moderate to severe AD. Seventeen patients with moderate-severe AD and 13 healthy volunteers underwent diffusion-weighted and T1-weighted MR scanning. Images were processed to obtain measures of macrostructural atrophy (gray and white matter 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 diffusion tensor imaging 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.

Hemangioblastomas of the lower spinal region: report of four cases with preoperative embolization and review of the literature.

BACKGROUND AND PURPOSE: Hemangioblastomas (HBs) are rare lesions accounting for 1-5% of all spinal cord tumors. Seventy-five percent of spinal HBs are intramedullary. Lesions of the conus medullaris and the cauda equina are uncommon, and the filum terminale location is very rare. HBs of the lower spinal region are highly vascular tumors requiring surgery that is potentially complicated by excessive bleeding. In the literature, there are few reports concerning preoperative embolization of HBs, and only few cases are reported in spinal location. Presurgical embolization of HBs located in the lower spinal region has not been described. Although lower spinal HBs are predominantly fed by the anterior spinal artery (ASA), embolization of these lesions is possible and can reduce tumor vascular supply, thus facilitating surgery. We report our experience in four rare cases of solitary HBs occurring in the lower spinal region. METHODS: Clinical charts and radiologic studies of four patients with a preoperatively embolized HB of the lower spinal region were retrospectively reviewed. The lesions were located in the conus medullaris in one case, at the level of the cauda equina in another, and in the filum terminale in two. In the conus medullaris case, the neoplasm was associated with a syrinx. In three patients, the HB was sporadic, while the patient with the HB of the cauda equina had Von Hippel-Lindau disease. Devascularization of the tumor was performed through the ASA in all cases and also through the posterior spinal artery in one by using non reabsorbable calibrated microspheres in three cases and polyvinyl alcohol particles in the other one. RESULTS: Embolization caused no permanent complications, although one patient with a cauda equina HB mildly worsened after the endovascular procedure but recovered before surgery. At surgery, the tumor was completely removed in all cases. Blood loss was reported to be less than usually observed (100, 200, 200, and 400 mL). In addition, manipulation and removal of the tumor was reported to be easy in three of four tumors. Histologic examination confirmed the diagnosis. At 1-year postsurgical follow-up, two patient recovered completely from neurologic deficits, and two showed significant recovery. No tumor recurred during a follow-up period of 1-6 years (mean, 3.5 years). CONCLUSION: Our results indicate that preoperative embolization of HBs of the lower spinal region is an useful procedure in aiding surgical resection of these highly vascular tumors. With a meticulous technique, embolization can be performed through the ASA.

Intra-arterial nimodipine for the treatment of symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage: preliminary results.

BACKGROUND AND PURPOSE: Cerebral vasospasm remains a major problem in patients recovering from aneurysmal subarachnoid hemorrhage despite advances in medical, surgical, and endovascular care. Our purpose was to assess the efficacy of intra-arterial nimodipine, a calcium-channel blocker acting mainly on cerebral vessels, in preventing delayed neurologic deficits in patients with symptomatic vasospasm. METHODS: Clinical charts of 25 consecutively treated patients were retrospectively reviewed. A multifactorial decision tree was used to determine the indication for angiography and subsequent endovascular treatment. Nimodipine was infused intra-arterially via a diagnostic catheter in the internal carotid artery or vertebral artery at a rate of 0.1 mg/min. Angiographic vasospasm before endovascular treatment, immediate vessel caliber modifications, and short- and long-term clinical efficacy of the procedure were assessed. RESULTS: Thirty procedures were performed in 25 patients. Clinical improvement was observed in 19 (76%), 16 of whom improved after the first endovascular procedure, two after the second intra-arterial treatment, and one after the third. Of these 19 patients, only 12 (63%) had notable vascular dilatation at postprocedural angiography. Dilatation of infused vessels occurred in only 13 (43%) of 30 procedures. After follow-up of 3-6 months, 18 (72%) of 25 patients had a favorable outcome (Glasgow outcome scale score of 1-2 and modified Rankin scale score of 0-2). No complications were observed. CONCLUSION: Intra-arterial nimodipine is effective and safe for the treatment of symptomatic vasospasm after subarachnoid hemorrhage. Further prospective randomized studies of cerebral blood flow are needed to confirm these results.

Cavernous sinus dural fistulae treated by transvenous approach through the facial vein: report of seven cases and review of the literature.

BACKGROUND AND PURPOSE: Dural Carotid Cavernous Fistulas (CCFs) can be treated by transarterial and/or transvenous endovascular techniques. The venous route usually goes through the internal jugular vein (IJV) and the inferior petrosal sinus (IPS) up to the pathologic shunts of the cavernous sinus. In case a thrombosed IPS, catheterization through the obstructed sinus is not always possible and a puncture of the superior ophthalmic vein (SOV) can be performed often after a surgical approach. We report our results in the endovascular transvenous treatment of dural CCFs through the facial vein (retrograde catheterization of the IJV, facial vein, angular vein, SOV, and cavernous sinus). METHODS: A retrospective study of seven patients with a dural CCF treated with transvenous embolization via the facial vein was performed. In five patients, the IPS was thrombosed. In one patient, the IPS was patent, but there was not communication between the cavernous sinus compartment in which the CCF shunts were located and the IPS itself. In the only patient with the CCF draining through permeable IPS, the transvenous route through the IPS permitted the occlusion of the posterior CCF shunts and a second session was performed through the facial vein in order to occlude the shunts of the anterior compartment of the cavernous sinus. The other six patients underwent one embolization session only. RESULTS: In all seven cases, it was possible to navigate through the tortuous junction of the angular vein and the SOV. In one patient with a thrombosed SOV, the venous procedure was interrupted because the catheterization through the occluded SOV failed. In the other six patients, after transvenous catheterization of the cavernous sinus via the facial vein, placement of coils resulted in complete occlusion of the dural CCF with clinical cure in four patients and improvement in two. CONCLUSION: In the endovascular treatment of the dural CCFs, the transfemoral approach via the facial vein provides a valuable alternative to other transvenous routes. Catheterization of the cavernous sinus via the facial vein is usually successful. Although this technique requires caution, it allows a safe and effective treatment of these lesions.