R. Elefante

Neural Processing of Auditory Looming in the Human Brain

Acoustic intensity change, along with interaural, spectral, and reverberation information, is an important cue for the perception of auditory motion. Approaching sound sources produce increases in intensity, and receding sound sources produce corresponding decreases. Human listeners typically overestimate increasing compared to equivalent decreasing sound intensity and underestimate the time to contact of approaching sound sources. These characteristics could provide a selective advantage by increasing the margin of safety for response to looming objects. Here, we used dynamic intensity and functional magnetic resonance imaging to examine the neural underpinnings of the perceptual priority for rising intensity. We found that, consistent with activation by horizontal and vertical auditory apparent motion paradigms, rising and falling intensity activated the right temporal plane more than constant intensity. Rising compared to falling intensity activated a distributed neural network subserving space recognition, auditory motion perception, and attention and comprising the superior temporal sulci and the middle temporal gyri, the right temporoparietal junction, the right motor and premotor cortices, the left cerebellar cortex, and a circumscribed region in the midbrain. This anisotropic processing of acoustic intensity change may reflect the salience of rising intensity produced by looming sources in natural environments.

Craniopharyngioma of the cranial base and nasopharynx

A rare case of craniopharyngioma extending to the cranial base and nasopharynx is reported and eight other cases in the literature are reviewed. The embryology and the clinical features of these tumors are discussed. Tomograms of the skull and computed tomography are the most useful radiological tools of investigation. A nasoseptal or transpalatal approach to surgery, which has been performed in reported cases of cystic nasopharyngeal craniopharyngiomas, was not performed on our patient because of the hard consistency and the diffusely infiltrating aspect of the tumor.

Criteria for the rank ordering of fMRI Independent Components

Introduction Independent Component Analysis (ICA) is a valuable tool for the data-driven analysis of fMRI time-series. Using ICA, BvlRI data are decomposed into 3D maps that are as independent as possible and have a unique associated time-course (I). Individual anatomical constraints can be used to limit the ICA to the “gray-matter” voxels and to enhance the capability of ICA to locate cortical sources (cortex-based ICA, (2)). In ICA methods, however, difficulties arise for the selection and the interpretation of the relevant independent components (ICs). First, the number of ICs is often very high, up to the number of functional scans. Second, it is usually uninformative to sort the ICs according to the variance that each of them explains in the original data. Since WRI-ICA might allow the detection of neural processes that are difficult to model a priori, a method of selection independent of the time-course of the activation is desirable. In this work, two of such methods are investigated and compared.

Tuber Cinereum Hamartomas and Gelastic Epilepsy

We studied five patients with gelastic epilepsy sustained by hamartoma of the tuber cinereum, submitted to EEG and Video-EEG study and to MR examination. The mechanism of ictal laughter, clinical associations and prognosis for seizure control are discussed. Hamartomas should be always suspected when gelastic seizures occur, and appropriate diagnostic tools should be employed for their diagnosis. In patients presenting with gelastic epilepsy, MR assessment of the hypothalamic region is necessary to identify a hamartoma of the tuber cinereum. Moreover, the resolution of MR imaging provides a basis to correlate some of the clinical manifestations with the anatomical disposition of the lesion within the hypothalamus. Gelastic epilepsy seems to correlate with large broad-based hamartomas in relationship with the mamillary bodies. In these cases, surgical treatment should be considered when symptoms are not sufficiently responsive to medical therapy.

Ectopic Suprasellar Pituitary Adenoma A Case Report

The occurrence of a pituitary adenoma located entirely outside the sella turcica, so-called ectopic adenoma, is extremely rare. We report a case of a non secreting-pituitary adenoma located above the diaphragma sellae, with no invasion into the sella turcica, confirmed at surgery. The tumor was initially treated unsuccessfully by operations via the transphenoidal route. After initial negative exploration by the transphenoidal route, the patient was successfully treated by an endoscopic endonasal transphenoidal approach extended to the tuberculum sellae and the posterior planum sphenoidale to access the suprasellar supraglandular region. A brief review of ectopic adenomas and a discussion of the preoperative diagnosis are presented.

Diagnostic Imaging of Paranasal Sinuses

The radiological study of paranasal sinuses has been facilitated by the natural contrast due to the presence of air within the cavities. A detailed study of bony structures has been obtained with the improvement of the tomographic techniqu~s, expecially when multidirectional, which, used with orthogonal planes, can reveal small lesions of the bony walls as well as small radiodense masses jutting out of the cavity. Further advancements in the radiodiagnosis of paranasal sinuses pathology are due to the advent of computed tomography This technique allows scanning of thin sections, on coronal and axial planes, showing at the same time sinusal cavities and their bony walls, soft tissues, adjacent to the sinuses or of the deep faci~l region, and the possible involvement of bram structures. The recently introduced process of magnetic resonance adds the possibility of multiplanar scans, arbitrarily oriented, and in spite of its poor resolution for bone has a diagnostic role, due to its high tissutal discrimination, expecially between tumoral and inflammatory lesions.

Functional MRI at High Field Strength

F. DI SALLE*****, T. SCARABINO***, F. ESPOSITO**, A. ARAGRI*, O. SANTOPAOLO*, A. ELEFANTE*, M. CIRILLO**, S. CIRILLO**, R. ELEFANTE* * Dipartimento di Scienze Neurologiche, Università Federico II di Napoli ** Dipartimento di Scienze Neurologiche, II Università di Napoli *** Neuroradiologia, Casa Sollievo della Sofferenza; S. Giovanni Rotondo, Foggia **** Dipartimento di Neuroscienze, Università di Pisa

Valutazione preoperatoria degli aneurismi intracranici con angio-TC spirale multislice:

Lo scopo di questo lavoro è valutare le informazioni fornite dall’angio-TC multislice nel pianificare un intervento chirurgico o endovascolare di aneurisma intracranico . L’angiografia digitale rimane la metodica di scelta per dimostrare la presenza di aneurismi del circolo intracranico, tuttavia il colletto, l’arteria d’origine ed i rapporti con i vasi adiacenti a volte sono di difficile valutazione, soprattutto in aneurismi di grosse dimensioni. L’angio-TC spirale è una tecnica poco invasiva, con sensibilità molto alta (97% per aneurismi > 3 mm) e può essere utilizzata come indagine di screening in pazienti asintomatici o con ESA . Attraverso procedure di elaborazione delle immagini è possibile ottenere una serie di informazioni aggiuntive a quelle fornite dall’angiografia digitale , utili per una programmazione terapeutica.

Erythrophagocytic Lymphohistiocytosis: MR Findings in Five Cases

Erythrophagocytic Lymphohistiocytosis (EL) is a rare disease characterized by a haemophagocytic syndrome and multisystem involvement including visceral organs, lymph nodes, bone marrow and central nervous system. We retrospectively assessed clinical, cytological and radiological data in five patients with EL. This study was aimed at assessing MR accuracy in the identification and characterization of central nervous system lesions. Our brain MR reports, correlating with pathologic findings described in literature, show a diffuse supra- and infratentorial white matter involvement, associated with deep gray matter infiltration. The overall effect of these reports allows a correct differential diagnosis from other white matter pediatric pathologies. In the only case without neurologic symptoms, brain MR revealed a diffuse atrophy. The only patient who received a bone marrow transplantation is currently in clinical remission; brain MR control showed a substantial stabilization of the central nervous system abnormalities. MR findings show a good correlation with areas of parenchymal and meningeal lymphohistiocytic infiltration; in addition, MR shows the possible stabilization of brain parenchyma abnormalities following bone marrow transplantation.

A Biochemical Approach to the Interpretation of MRI Images: In Vitro Study on a Craniopharyngioma

Magnetic resonance imaging (MRI) provides very promising possibilities in tissue characterization. MRI signal intensity is a complex function of four independent tissue parameters (T1, T2, proton density, and proton flow) and it is influenced by the chosen acquisition sequence (Bradley 1987). The multiple factors that affect MRI signal intensity and the possibility of selecting the most effective acquisition parameters can emphasize tissue contrast. On the other hand, complexity of variables increases the difficulties in establishing a precise correlation between signal intensity and the biochemical composition of the examined tissue (Biagini 1986).