Renzo Minotto

Glial brain tumor detection by using symmetry analysis

In this work a fully automatic algorithm to detect brain tumors by using symmetry analysis is proposed. In recent years a great effort of the research in field of medical imaging was focused on brain tumors segmentation. The quantitative analysis of MRI brain tumor allows to obtain useful key indicators of disease progression. The complex problem of segmenting tumor in MRI can be successfully addressed by considering modular and multi-step approaches mimicking the human visual inspection process. The tumor detection is often an essential preliminary phase to solvethe segmentation problem successfully. In visual analysis of the MRI, the first step of the experts cognitive process, is the detection of an anomaly respect the normal tissue, whatever its nature. An healthy brain has a strong sagittal symmetry, that is weakened by the presence of tumor. The comparison between the healthy and ill hemisphere, considering that tumors are generally not symmetrically placed in both hemispheres, was used to detect the anomaly. A clustering method based on energy minimization through Graph-Cut is applied on the volume computed as a difference between the left hemisphere and the right hemisphere mirrored across the symmetry plane. Differential analysis involves the loss the knowledge of the tumor side. Through an histogram analysis the ill hemisphere is recognized. Many experiments are performed to assess the performance of the detection strategy on MRI volumes in presence of tumors varied in terms of shapes positions and intensity levels. The experiments showed good results also in complex situations.

Lhermitte-duclos disease: A case report

Lhermitte-Duclos disease is a rare pathologic condition consisting of a dysplastic gangliocytoma of the cerebellum. Its association with phacomatosis and an autosomal dominant neoplastic syndrome, Cowdens syndrome is also known. Modern neuroimaging contributes to a correct diagnosis and pre- and postoperative evaluation. Here we describe the morphologic and metabolic aspects of the disease as shown by conventional MRI, diffusion imaging and spectroscopy in a 31-year-old woman. In addition, the specific neuroradiologic characteristics are presented and discussed in the light of the main pathologic and clinical features, such as hypertrophy of the cerebellar folia associated with white matter atrophy.

Flow-diverter stenting in post-traumatic pseudoaneurysm of cavernous internal carotid artery with epistaxis

This paper is a case report of a young patient after a major head trauma causing multiple skull base fractures. The trauma occasioned pseudoaneurysm (PSA) from intracavernous C4 segment of left internal carotid artery (ICA) protruding in the sphenoidal sinus. After two months, two episodes of massive epistaxis occurred. Consequently, the post-traumatic PSA was treated, after carotid occlusion test, with flow-diverter stent positioning. A computed tomography angiography study performed in the following days showed complete resolution of the post-traumatic PSA lesion and ICA patency.

Flow-diverter stenting of post-traumatic bilateral anterior cerebral artery pseudoaneurysm: A case report:

The use of flow-diverter (FD) stents in recent years has positively changed the therapeutic approach to some vascular diseases, especially of certain types of aneurysms. This paper describes the case of a young patient after a major head trauma causing multiple skull fractures. The trauma occasioned two pseudoaneurysms from the A1 segment of the right anterior cerebral artery and from the A2 segment of the left anterior cerebral artery. Both lesions were treated with two Pipeline devices (ev3, Irvine, CA, USA) in two different sessions. The CT study and angiographic investigations performed in the following month showed a complete resolution of the post-traumatic pseudoaneurysmal lesions. Although the use of FD stents is described in the literature, particularly in the treatment of selected aneurysms, this paper shows good technical results in the use of these stents in cases of intracranial post-traumatic pseudoaneurysms with clinical improvement.

Endovascular Treatment of Extracranial Internal Carotid Pseudoaneurysm: Description of Three Cases

The aim of this study is to explore the possibility of endovascular treatment of internal carotid artery pseudoaneurysm (PSA). These lesions are difficult to treat with a surgical approach, especially if they are located extracranially and close to the skull base. Endovascular stent placement in symptomatic and unstable extracranial internal carotid PSA was found to be safe and effective. Depending on hemodynamic aspects, complete local exclusion of aneurysmal formation is achieved in few months. We present three patients with carotid dissection and PSA formation that have been successfully treated by stent placement.

Computation and management of weighted activation vectors in support to fMRI analysis of clinical subjects

ABSTRACT In the present work, we investigate the usefulness of a new representation of the results obtained by fMRI data analysis, named weighted activation vector (WAV), built based on statistical parametric mapping. A software package for the generation and management of WAVs is illustrated. It is designed to support single-subject, multi-temporal and collective brain tumour studies. As seen in our experimental context, the combined use of WAVs and statistical parametric maps (SPMs) improves the quality of medical decisions before and after neurosurgical practice. Clustering techniques applied to WAVs can be efficiently analysed and optimised in an attempt to discover relevant properties of collective data.

On the Evaluation of Automated MRI Brain Segmentations: Technical and Conceptual Tools

The present work deals with segmentation of Glial Tumors in MRI images focusing on critical aspects in manual labeling and reference estimation for segmentation validation purposes. A reproducibility analysis was conducted confirming the presence of different sources of uncertainty involved in the process of manual segmentation and responsible of high intra-operator and inter-operator variability. Technical and conceptual solutions aimed to reduce operator variability and support in the reference estimation process are integrated in GliMAn (Glial Tumor Manual Annotator), an application allowing to view and manipulate MRI volumes and implementing a label fusion strategy based on fuzzy connectedness. A set of experiments was conceived and conducted to evaluate the contribution of the solutions proposed in the process of manual segmentation and reference data estimation.

Necrosi avascolare idiopatica del corpo vertebrale: Trattamento mediante vertebroplastica percutanea: Descrizione di un caso e revisione della letteratura

La necrosi avascolare idiopatica del corpo vertebrale è una patologia infrequente . L’osteonecrosi vertebrale è infatti più spesso associata con altre patologie , quali diabete, alcolismo, traumi, infezioni, osteoporosi , pancreatiti , vasculiti, cirrosi ; oppure secondaria a trattamenti prolungati con corticosteroidi 4,5,7 o a terapie radianti . Strettamente associato alla necrosi avascolare del corpo vertebrale è il fenomeno del “vacuum cleft” , apprezzabile sulle radiografie: tale fenomeno, in accordo con le teorie patogenetiche più comunemente accettate, costituisce un segno patognomonico 4,7,8,10 di osteonecrosi della vertebra, insieme al collasso del corpo vertebrale e all’addensamento della trama ossea. Per porre diagnosi di necrosi avascolare del corpo vertebrale bisogna prima di tutto escludere altre possibili cause di collasso somatico, soprattutto una localizzazione neoplastica primitiva o secondaria; inoltre il “vacuum cleft” pone il problema di una diagnosi differenziale con un processo infettivo.