Sergio Balbi

Glioblastoma multiforme (GBM) is usually treated with surgery followed by adjuvant partial radiotherapy combined with temozolomide (TMZ) chemotherapy. Recent studies demonstrated a better survival and good response to TMZ in methylguanine-DNA methyltransferase (MGMT)-methylated GBM cases. However, approximately 20% of patients with MGMT-unmethylated GBM display an unexpectedly favorable outcome. Therefore, additional mechanisms related to the TMZ response need to be investigated. As such, we decided to investigate the clinical relevance of six miRNAs involved in brain tumorigenesis (miR-181c, miR-181d, miR-21, miR-195, miR-196b, miR-648) as additional markers of response and survival in patients receiving TMZ for GBM. We evaluated miRNA expression and the interplay between miRNAs in 112 IDH wt GBMs by applying commercial assays. Then, we correlated the miRNA expression with patients’ clinical outcomes. Upon bivariate analyses, we found a significant association between the expression levels of the miRNAs analyzed, but, more interestingly, the OS curves show that the combination of low miR-648 and miR-181c or miR-181d expressions is associated with a worse prognosis than cases with other low-expression miRNA pairs. To conclude, we found how specific miRNA pairs can influence survival in GBM cases treated with TMZ.

This work focuses the attention on the segmentation of meningioma and peritumoral edema from multispectral brain MR imagery. Precise tumour and edema delineation and volume quantification from preoperative MRI data contribute to formulate surgical indications in elderly patients harbouring intracranial meningioma. The authors propose a fully automatic procedure based on the allied use of Graph Cut and support vector machine. The overall strategy combines the advantages of the image-based and machine learning techniques adopted, optimising the balancing between accuracy and stability/reproducibility of the results. Experimental results, obtained by processing in-house collected data, prove that the method is robust and oriented to the use in clinical practice.

Peritumoral brain edema is a frequently encountered phenomenon that strongly contributes to neurological signs and symptoms. This paper presents a fully automated procedure based on Support Vector Machine for the accurate and efficient edema delineation in brain MRI imagery. The segmentation procedure is conceived fully automatic and specifically oriented to non-volumetric data to facilitate the insertion in clinical practice. The major efforts in building a robust classifier were concentrated in the extraction and selection of a set of significant features from multispectral brain MR images. Preliminary experimental results obtained by processing in-house collected data, are encouraging creating the premises for an effective use of the automated segmentation procedure in brain tumor clinical studies. To see if the proposed supervised method can be considered an alternative to other contemporary approaches, the results obtained were compared with those obtained by an unsupervised region-based segmentation procedure based on Graph Cut

Objectives Although diffusion tensor imaging (DTI) and postmortem dissections improved the knowledge of white matter (WM) anatomy, functional information is lacking. Our aims are: to provide a subcortical atlas of human brain functions; to elucidate the functional roles of different bundles; to provide a probabilistic resection map of WM. Experimental design We studied 130 patients who underwent awake surgery for gliomas (82 left; 48 right) with electrostimulation mapping at cortical and subcortical levels. Different aspects of language, sensori‐motor, spatial cognition, and visual functions were monitored. 339 regions of interest (ROIs) including the functional response errors collected during stimulation were co‐registered in the MNI space, as well as the resections’ areas and residual tumors. Functional response errors and resection areas were matched with DTI and cortical atlases. Subcortical maps for each function and a probability map of resection were computed. Principal observations The medial part of dorsal stream (arcuate fasciculus) subserves phonological processing; its lateral part [indirect anterior portion of the superior longitudinal fascicle (SLF)] subserves speech planning. The ventral stream subserves language semantics and matches with the inferior fronto‐occipital fascicle. Reading deficits match with the inferior longitudinal fascicle. Anomias match with the indirect posterior portion of the SLF. Frontal WM underpins motor planning and execution. Right parietal WM subserves spatial cognition. Sensori‐motor and visual fibers were the most preserved bundles. Conclusions We report the first anatomo‐functional atlas of WM connectivity in humans by correlating cognitive data, electrostimulation, and DTI. We provide a valuable tool for cognitive neurosciences and clinical applications. Hum Brain Mapp 36:3117–3136, 2015.

Rusconi A, et al. J Korean Neurosurg Soc. 2015 May;57(5):379-385. http://dx.doi.org/10.3340/jkns.2015.57.5.379

The temporo‐parieto‐occipital (TPO) junction is a complex brain territory heavily involved in several high‐level neurological functions, such as language, visuo‐spatial recognition, writing, reading, symbol processing, calculation, self‐processing, working memory, musical memory, and face and object recognition. Recent studies indicate that this area is covered by a thick network of white matter (WM) connections, which provide efficient and multimodal integration of information between both local and distant cortical nodes. It is important for neurosurgeons to have good knowledge of the three‐dimensional subcortical organisation of this highly connected region to minimise post‐operative permanent deficits. The aim of this dissection study was to highlight the subcortical functional anatomy from a topographical surgical perspective. Eight human hemispheres (four left, four right) obtained from four human cadavers were dissected according to Klingler's technique. Proceeding latero‐medially, the authors describe the anatomical courses of and the relationships between the main pathways crossing the TPO. The results obtained from dissection were first integrated with diffusion tensor imaging reconstructions and subsequently with functional data obtained from three surgical cases, all resection of infiltrating glial tumours using direct electrical mapping in awake patients. The subcortical limits for performing safe lesionectomies within the TPO region are as follows: within the parietal region, the anterior horizontal part of the superior longitudinal fasciculus and, more deeply, the arcuate fasciculus; dorsally, the vertical projective thalamo‐cortical fibres. For lesions located within the temporal and occipital lobes, the resection should be tailored according to the orientation of the horizontal associative pathways (the inferior fronto‐occipital fascicle, inferior longitudinal fascicle and optic radiation). The relationships between the WM tracts and the ventricle system were also examined. These results indicate that a detailed anatomo‐functional awareness of the WM architecture within the TPO area is mandatory when approaching intrinsic brain lesions to optimise surgical results and to minimise post‐operative morbidity.

Pituitary apoplexy is a rare endocrine emergency that occurs in a small number of patients with a pituitary tumor. It is a clinical syndrome characterized by the sudden onset of headache, nausea, vomiting, visual impairment, and decreased consciousness, caused by hemorrhage and/or infarction of the pituitary gland. Pituitary apoplexy has very rarely been described during pregnancy, when it is potentially life-threatening to both the mother and the fetus, if unrecognized. Only a few cases have been published to date. The review of the existing literature underlines that pituitary apoplexy, although rare, should be borne in mind when a pregnant woman presents with severe headache and visual defects of sudden onset. After initial management, which includes intravenous glucocorticoid therapy, fluid and electrolyte replacement, the final selection of medical or surgical treatment should result from a multidisciplinary approach involving expert specialists, keeping into account both severity of clinical presentation and gestational week.

In this work, we propose a novel behavioural comparison strategy specifically oriented to accuracy assessment in MRI glial tumour segmentation studies. A salient aspect of the proposed strategy is the use of the fuzzy set framework in modelling visual inspection and interpretation processes. In particular, a reference estimation strategy based on fuzzy connectedness principles is designed to merge individual labels and produce a common segmentation. The estimation is based exclusively on highly reliable partial information provided by experts. Interaction is then drastically limited compared with a complete manual tracing, leaving the estimation of the complete segmentation to the fuzzy connectedness method. A set of experiments was conceived and conducted to evaluate the contribution of the solutions proposed in the process of truth label collection and reference data estimation. A comparison analysis was also developed to see whether our method could constitute a worthy alternative to well-known and state-of-the-art solutions.