Advanced MRI may complement histological diagnosis of lower grade gliomas and help in predicting survival.

MRI grading of grade II and III gliomas may have an important impact on treatment decisions. Occasionally,both conventional MRI (cMRI) and histology fail to clearly establish the tumour grade. Three cMRI features(no necrosis; no relevant oedema; absent or faint contrast enhancement) previously validated in 196 patients with supratentorial gliomas directed our selection of 68 suspected low-grade gliomas (LGG) that were also investigated by advanced MRI (aMRI), including perfusion weighted imaging (PWI), diffusion weighted imaging(DWI) and spectroscopy. All the gliomas had histopathological diagnoses. Sensitivity and specificity of cMRI preoperative diagnosis were 78.5 and 38.5 %, respectively, and 85.7 and 53.8 % when a MRI was included, respectively. ROC analysis showed that cut-off values of 1.29 for maximum rCBV, 1.69 for minimum rADC, 2.1 for rCho/Cr ratio could differentiate between LGG and HGG with a sensitivity of 61.5, 53.8, and 53.8 % and a specificity of 54.7, 43 and 64.3 %, respectively. A significantly longer OS was observed in patients with a maximum rCBV<1.46 and minimum rADC>1.69 (80 vs 55 months, p = 0.01; 80 vs 51 months, p = 0.002, respectively). This result was also confirmed when cases were stratified according to pathology (LGG vs HGG). The ability of a MRI to differentiate between LGG and HGG and to predict survival improved as the number of a MRI techniques considered increased. In a selected population of suspected LGG,classification by cMRI underestimated the actual fraction of HGG. aMRI slightly increased the diagnostic accuracy compared to histopathology. However, DWI and PWI were prognostic markers independent of histological grade.

Enhanced torque-based impedance control to assist brain targeting during open-skull neurosurgery: a feasibility study.

BACKGROUND: Cooperatively-controlled robotic assistance could provide increased positional accuracy and stable and safe tissue targeting tasks during open-skull neurosurgical procedures, which are currently performed free-hand. METHODS: Two enhanced torque-based impedance control approaches, i.e. a variable damping criterion and a force-feedback enhancement control, were proposed in combination with an image-based navigation system. Control systems were evaluated on brain-mimicking phantoms by 13 naive users and 8 neurosurgeons (4 novices and 4 experts). RESULTS: In addition to a 60% reduction of user effort, the combination of the proposed strategies showed comparable performances with respect to state-of-the-art admittance controller, thus satisfying the clinical accuracy requirements (below 1 mm), reducing the hand tremor (by a factor of 10) and the tissue's indentation overshooting (by 80%). CONCLUSION: Although the perceived reliability of the system should be improved, the proposed control was suitable to assist targeting procedures, such as brain cortex stimulation, allowing for accurate, stable and safe contact with soft tissues. Copyright © 2015 John Wiley & Sons, Ltd.

Iatrogenic intracranial pseudoaneurysms: neuroradiological and therapeutical considerations, including endovascular options.

Intracranial pseudoaneurysms represent a potentially fatal complication of intracranial surgery. Our purpose is to describe their neuroradiological characteristics, prognostic features and possible treatment. Eight cases of postsurgical intracranial pseudoaneurysms have been observed at our institution since 1988. Four were observed following transsphenoidal (TS) surgery and four after pterional craniotomies. Two types of iatrogenic pseudoaneurysms were observed: "fusiform", probably due to weakening of the adventitia during surgical peeling of the tumour from the artery (three cases) and "saccular", occurring after a more focal or complete laceration of the vessel (five cases), more often after TS surgery. A thorough preoperative neuroradiological examination may identify anatomical conditions at risk for development of this severe complication. Postoperative neuroradiological follow-up is mandatory in cases in which unusual bleeding has occurred during the perioperative period, but absence of bleeding does not exclude the possible development of a pseudoaneurysm. Endovascular treatment of pseudoaneurysms represents a safe and durable procedure, specifically in those cases in which damage to the carotid siphon occurred during TS surgery.

Local drug delivery in recurrent malignant gliomas.

In recurrent malignant gliomas, we scheduled a protocol by adding to systemic temozolomide a local treatment delivered through a reservoire positioned in the surgically created cavity, consisting of either mitoxantrone, liposome-loaded doxorubicine or nimustine (ACNU). The progression-free survival (PFS) and survival time (ST) of the whole group of 112 patients were 8.3 and 11 months, respectively, in GBM patients, and 14 and 18 months in AA patients. To limit the selection bias in recruitment we matched locally treated patients with the whole group of patients treated for 3 years and having undergone the same protocol with the exception of local drug delivery. Variables such as age, histology and local chemotherapy delivery were proved to be statistically significant independent factors on adjunctive PFS and ST. Another group of 12 recurrent malignant gliomas with further progression was locally managed according to convection-enhanced delivery (CED) of mitoxantrone; the preliminary results show good tolerability of the schedule.

Gene therapy of experimental brain tumors using neural progenitor cells.

Glioblastomas, the most frequent and malignant of primary brain tumors, have a very poor prognosis. Gene therapy of glioblastomas is limited by the short survival of viral vectors and by their difficulty in reaching glioblastoma cells infiltrating the brain parenchyma. Neural stem/progenitor cells can be engineered to produce therapeutic molecules and have the potential to overcome these limitations because they may travel along the white matter, like neoplastic cells, and engraft stably into the brain. Retrovirus-mediated transfer of the gene for interleukin-4 is an effective treatment for rat brain glioblastomas. Here, we transferred the gene for interleukin-4 into C57BL6J mouse primary neural progenitor cells and injected those cells into established syngeneic brain glioblastomas. This led to the survival of most tumor-bearing mice. We obtained similar results by implanting immortalized neural progenitor cells derived from Sprague-Dawley rats into C6 glioblastomas. We also documented by magnetic resonance imaging the progressive disappearance of large tumors, and detected 5-bromodeoxyuridine-labeled progenitor cells several weeks after the injection. These findings support a new approach for gene therapy of brain tumors, based on the grafting of neural stem cells producing therapeutic molecules.

Gene transfer of suicide genes for the treatment of malignant gliomas: efficacy, limitations, and perspectives for a combined immunotherapy.

The potential of gene therapy strategies for malignant gliomas that are based on retroviral-mediated transfer of a "suicide gene" such as Herpes Simplex Virus-thymidine kinase HSV-tk and subsequent treatment by a prodrug (ganciclovir, for example), has been emphasized by the promising results obtained by several groups. However, further experimental data as well as preliminary clinical results indicate that the low efficiency of retroviral-mediated gene transfer in vivo as well as difficulties for the diffusion of the prodrug inside the tumour mass can limit the efficacy of this form of gene therapy. To achieve a more effective limitation of tumour growth other approaches may be combined with the "suicide gene" strategy and the enhancement of the immunological response to the tumour by cytokine gene transfer is prominent among these approaches. The authors' experiments in nude mice confirm the antineoplastic role of IL-4 and encourage testing the effects of the simultaneous transfer of IL-4 and HSV-tk genes in immunocompetent animals.

Perspectives for the gene therapy of malignant gliomas by suicide gene transfer.

A promising strategy in the treatment of malignant gliomas involves the creation of Herpes Simplex Virus-thymidine kinase (HSV-tk) modified tumor cells. Some authors have observed complete tumor regression after ganciclovir (GCV) treatment of established gliomas transduced in vivo by the HSV-tk gene. Yet, further investigations did not confirm completely these results, even if confirmed the therapeutic potential of such a therapy. Using the rat C6 glioblastoma as a model of malignant brain tumor, we investigated the efficacy of in vivo and in vitro transduction of growing brain tumors with the HSV-tk gene, followed by GCV administration. The stereotactic injection into the left striatum of C6 cells mixed with retroviral producer cells and GCV treatment did not improve significantly the animal survival compared to controls. On the contrary, there was a significant prolongation of the survival of rats inoculated with C6 cells engineered in vitro to express the HSV-tk gene. Nevertheless, complete eradication of the tumors was not achieved. We also injected a group of six rats with a mixture of cells expressing the murine Interleukin-4 (IL-4) gene and C6 cells. IL-4 has been shown to produce the regression of experimental brain tumors. Our preliminary experience seems to confirm that hypothesis. Our results indicate that the outcome of HSV-tk gene therapy can be limited not only by low gene transfer but also by insufficient delivery of GCV to tumor cells. Combined strategies, based on contemporary transduction of HSV-tk and IL-4, may enhance the therapeutic perspectives of such a therapy.

[Etiopathogenesis of dilated cardiomyopathies]. / Eziopatogenesi delle cardiomiopatie dilatative.

This study was carried out on 43 patients affected by dilated cardiomyopathy to investigate some of the etiopathological hypotheses on this illness. The Authors investigated: the persistence of virus genoma (coxsackie, HBV) on endomyocardial biopsies; the pattern of the II class major histocompatibility complex (MHC) were in the blood lymphocytes; the microvascular aspect of coronary circulation in the endomyocardial biopsies. Finally, in a separated group of 19 patients, the microvascular circulation was studied on skin biopsies and correlated with diabetic, valvular and normal subject. The results showed a 14% positivity for the presence of the virus genoma and a significant predominate of DR5 in the II class MHC of patients with a worse ventricular function. Capillary vessels of the coronary microcirculation were dilated in the 48% of the patients, especially in more compromised subjects. Viral myocarditis seem to play a role in the etiopathogenesis of dilated cardiomyopathies (DCM) and the pattern of MHC could influence the progression of the illness. The microcirculation is probably a pathophysiological aspect. No etiological hypothesis seems to predominate.