Imaging of inner ear malformations: a primer for radiologists

In the multidisciplinary management of patients with inner ear malformations (IEMs), the correct diagnosis makes the differences in terms of clinical and surgical treatment. The complex anatomical landscape of the inner ear, comprising several small structures, makes imaging of this region particularly challenging for general radiologists. Imaging techniques are important for identifying the presence and defining the type of IEM and the cochlear nerve condition. High-resolution magnetic resonance imaging (MRI) sequences and high-resolution computed tomography (HRCT) are the mainstay imaging techniques in this area. Dedicated MRI and HRCT protocols play an important role in the diagnosis and treatment of patients with inner ear disease. The most suitable technique should be selected depending on the clinical setting. However, in cases of congenital malformation of the inner ear, these techniques should be considered complementary. Since prompt intervention has a positive impact on the treatment outcomes, early diagnosis of IEMs is very important in the management of deaf patients. This article reviews the key concepts of IEMs for clinical radiologists by focusing on recent literature updates, discusses the principal imaging findings and clinical implications for every IEM subgroup, thus providing a practical diagnostic approach

Finding home: the final step of the pigeons' homing process studied with a GPS data logger

Experiments have shown that homing pigeons are able to develop navigational abilities even if reared and kept confined in an aviary, provided that they are exposed to natural winds. These and other experiments performed on inexperienced birds have shown that previous homing experiences are not necessary to determine the direction of displacement. While the cues used in the map process for orienting at the release site have been extensively investigated, the final step of the homing process has received little attention by researchers. Although there is general agreement on the relevance of visual cues in navigation within the home area, there is a lack of clear evidence. In order to investigate the final step of the homing process, we released pigeons raised under confined conditions and others that had been allowed to fly freely around the loft and compared their flight paths recorded with a Global-Positioning-System logger. Our data show that a limited view of the home area impairs the pigeons' ability to relocate the loft at their first homing flight, suggesting that the final step of the homing process is mediated via recognition of familiar visual landmarks in the home area

Homing Pigeons Only Navigate in Air with Intact Environmental Odours: A Test of the Olfactory Activation Hypothesis with GPS Data Loggers

A large body of evidence has shown that anosmic pigeons are impaired in their navigation. However, the role of odours in navigation is still subject to debate. While according to the olfactory navigation hypothesis homing pigeons possess a navigational map based on the distribution of environmental odours, the olfactory activation hypothesis proposes that odour perception is only needed to activate a navigational mechanism based on cues of another nature. Here we tested experimentally whether the perception of artificial odours is sufficient to allow pigeons to navigate, as expected from the olfactory activation hypothesis. We transported three groups of pigeons in air-tight containers to release sites 53 and 61 km from home in three different olfactory conditions. The Control group received natural environmental air; both the Pure Air and the Artificial Odour groups received pure air filtered through an active charcoal filter. Only the Artificial Odour group received additional puffs of artificial odours until release. We then released pigeons while recording their tracks with 1 Hz GPS data loggers. We also followed non-homing pigeons using an aerial data readout to a Cessna plane, allowing, for the first time, the tracking of non-homing homing pigeons. Within the first hour after release, the pigeons in both the Artificial Odour and the Pure Air group (receiving no environmental odours) showed impaired navigational performances at each release site. Our data provide evidence against an activation role of odours in navigation, and document that pigeons only navigate well when they perceive environmental odours

Conventional MRI-Derived Biomarkers of Adult-Type Diffuse Glioma Molecular Subtypes: A Comprehensive Review

The introduction of molecular criteria into the classification of diffuse gliomas has added interesting practical implications to glioma management. This has created a new clinical need for correlating imaging characteristics with glioma genotypes, also known as radiogenomics or imaging genomics. Although many studies have primarily focused on the use of advanced magnetic resonance imaging (MRI) techniques for radiogenomics purposes, conventional MRI sequences remain the reference point in the study and characterization of brain tumors. A summary of the conventional imaging features of glioma molecular subtypes should be useful as a tool for daily diagnostic brain tumor management. Hence, this article aims to summarize the conventional MRI features of glioma molecular subtypes in light of the recent literature

Clinical and brain imaging findings in a child with vitamin B12 deficiency

Vitamin B12 (Vit-B12) deficiency is a rare and treatable cause of failure to thrive and delayed development in infants who are exclusively breastfed. Apart from genetic causes, it can be related to a malabsorption syndrome or when the mother follows a strict vegetarian or vegan diet, causing a low hepatic storage of Vit-B12 in the infant at birth. As the neurological symptoms are nonspecific, a brain magnetic resonance imaging (MRI) exam is usually performed to rule out primary causes of neurodevelopmental delay. Findings related to brain atrophy are usually observed. A favorable response is achieved with Vit-B12 therapy, and neurological symptoms dramatically improve within a few days after the treatment. We present the case of an infant with severe Vit-B12 deficiency, exclusively breastfed by his young vegan mother, and whose clinical symptoms together with MRI findings improved after treatment. Brain atrophy recovery after Vit-B12 therapy has been seldom documented

Isolated, subtle, neurological abnormalities in neurologically and cognitively healthy aging subjects

The aim of this study is to describe the frequency of isolated, subtle, neurological abnormalities (ISNAs) in a large population of neurologically and cognitively healthy subjects and to compare ISNAs to various types of MRI-detected cerebrovascular lesions and subcortical brain atrophy in different age classes. 907 subjects were selected from a large, prospective hospital-based study. At baseline neurological examination, 17 ISNAs were selected. Primitive reflexes were the most common ISNAs (35.8 %), while dysphagia was the most rarely encountered (0.3 %). Measures of small vessel disease, i.e., deep and subcortical white matter hyperintensity and lacunar infarcts as well as subcortical atrophy, were variously associated with ISNAs. In the adult group, the ISNAs were associated with hypertriglyceridemia, TIA, and subcortical lacunar infarcts, while in the elderly-old group they were associated with arterial hypertension, subcortical white matter hyperintensity, and subcortical atrophy. An increased risk of ISNAs was associated with lacunae and white matter hyperintensity in the parietal region. This study shows that white matter hyperintensity, lacunae, and subcortical atrophy are associated with an increased risk of ISNAs in cognitively and neurologically healthy aging subjects. ISNAs are not benign signs. Therefore, adults and elderly people presenting with ISNAs should have access to accurate history and diagnosis to prevent progression of small vessel disease and future neurological and cognitive disabilities

A novel heteroditopic terpyridine-pincer ligand as building block for mono- and heterometallic Pd(II) and Ru(II) complexes

A palladium-catalyzed Stille coupling reaction was employed as a versatile method for the synthesis of a novel terpyridine-pincer (3, TPBr) bridging ligand, 4'-{4-BrC6H2(CH2NMe2)(2)-3,5}-2,2':6',2 ''-terpyridine. Mononuclear species [PdX(TP)] (X = Br, Cl), [Ru(TPBr)(tpy)](PF6)(2), and [Ru(TPBr)(2)](PF6)(2), synthesized by selective metalation of the NCNBr-pincer moiety or complexation of the terpyridine of the bifunctional ligand TPBr, were used as building blocks for the preparation of heterodi- and trimetallic complexes [Ru(TPPdCl)(tpy)](PF6)(2) (7) and [Ru(TPPdCl)(2)]-(PF6)(2) (8). The molecular structures in the solid state of [PdBr(TP)] (4a) and [Ru(TPBr)(2)](PF6)(2) (6) have been determined by single-crystal X-ray analysis. Electrochemical behavior and photophysical properties of the mono-and heterometallic complexes are described. All the above di- and trimetallic Ru complexes exhibit absorption bands attributable to (MLCT)-M-1 (Ru -> tpy) transitions. For the heteroleptic complexes, the transitions involving the unsubstituted tpy ligand are at a lower energy than the tpy moiety of the TPBr ligand. The absorption bands observed in the electronic spectra for TPBr and [PdCl(TP)] have been assigned with the aid of TD-DFT calculations. All complexes display weak emission both at room temperature and in a butyronitrile glass at 77 K. The considerable red shift of the emission maxima relative to the signal of the reference compound [Ru(tpy)(2)](2+) indicates stabilization of the luminescent (MLCT)-M-3 state. For the mono- and heterometallic complexes, electrochemical and spectroscopic studies (electronic absorption and emission spectra and luminescence lifetimes recorded at room temperature and 77 K in nitrile solvents), together with the information gained from IR spectroelectrochemical studies of the dimetallic complex [Ru(TPPdSCN)(tpy)](PF6)(2), are indicative of charge redistribution through the bridging ligand TPBr. The results are in line with a weak coupling between the {Ru(tpy)(2)} chromophoric unit and the (non)metalated NCN-pincer moiety

Olfactory lateralization in homing pigeons: a GPS study on birds released with unilateral olfactory inputs

A large body of evidence has shown that pigeons rely on an olfactory-based navigational map when homing from unfamiliar locations. Previous studies on pigeons released with one nostril occluded highlighted an asymmetry in favour of the right nostril, particularly concerning the initial orientation performance of naïve birds. Nevertheless, all pigeons experiencing only unilateral olfactory input showed impaired homing, regardless of the side of the occluded nostril. So far this phenomenon has been documented only by observing the birds’ vanishing bearings. In the present work we recorded the flight tracks of pigeons with previous homing experience equipped with a GPS data logger and released from an unfamiliar location with the right or the left nostril occluded. The analysis of the tracks revealed that the flight path of the birds with the right nostril occluded was more tortuous than that of unmanipulated controls. Moreover, the pigeons smelling with the left nostril interrupted their journey significantly more frequently and displayed more exploratory activity than the control birds, e.g. during flights around a stopover site. These data suggest a more important involvement of the right olfactory system in processing the olfactory information needed for the operation of the navigational map

Encefalopatia ipertensiva cronica (EIC): sensibilita\u300 delle sequenze GE-T2* a confronto con le SWI nell'identificazione dei micro-sanguinamenti

L'EIC e\u300 caratterizzata dalla presenza di lesioni parenchimali irreversibili, risultato di una lunga esposizione a regimi pressori patologici specie in pazienti che non seguono o non rispondono alle comuni terapie mediche. Si riscontrano quali reperti tipici multipli esiti gliotici, leucoaraiosi e multiple lesioni lacunari con predilezione per le localizzazioni profonde ai nuclei lenticolari, ai talami e al ponte. Piu\u300 raramente possono evidenziarsi minuti foci emorragici parenchimali, piu\u300 frequentemente localizzati nei gangli della base ma anche nel ponte e nel cervelletto, che in alcuni casi possono rappresentare la manifestazione principale della patologia: questi microsanguinamenti, visibili incostantemente in TC, sono classicamente ben individuabili in RM come aree di netta ipointensita\u300 di segnale in GRE (Gradient Recalled Echo) T2* pesate. Scopo del nostro lavoro e\u300 quello di presentare due casi in cui l'EIC si manifesta prevalentemente con un quadro micro-emorragico confrontando la sensibilita\u300 delle convenzionali sequenze GRE T2* pesate con sequenze sensibili al fenomeno della suscettivita\u300 magnetica (Susceptibility-Weighted Imaging, SWI) di piu\u300 recente introduzione nella routine diagnostica

Weak formulation for singular diffusion equation with dynamic boundary condition

In this paper, we propose a weak formulation of the singular diffusion equation subject to the dynamic boundary condition. The weak formulation is based on a reformulation method by an evolution equation including the subdifferential of a governing convex energy. Under suitable assumptions, the principal results of this study are stated in forms of Main Theorems A and B, which are respectively to verify: the adequacy of the weak formulation; the common property between the weak solutions and those in regular problems of standard PDEs.Comment: 23 page