3-d residual eddy current field characterisation: applied to diffusion weighted magnetic resonance imaging.

Clinical use of the Stejskal-Tanner diffusion weighted images is hampered by the geometric distortions that result from the large residual 3-D eddy current field induced. In this work, we aimed to predict, using linear response theory, the residual 3-D eddy current field required for geometric distortion correction based on phantom eddy current field measurements. The predicted 3-D eddy current field induced by the diffusion-weighting gradients was able to reduce the root mean square error of the residual eddy current field to ~1 Hz. The model's performance was tested on diffusion weighted images of four normal volunteers, following distortion correction, the quality of the Stejskal-Tanner diffusion-weighted images was found to have comparable quality to image registration based corrections (FSL) at low b-values. Unlike registration techniques the correction was not hindered by low SNR at high b-values, and results in improved image quality relative to FSL. Characterization of the 3-D eddy current field with linear response theory enables the prediction of the 3-D eddy current field required to correct eddy current induced geometric distortions for a wide range of clinical and high b-value protocols.

Accelerated MR imaging with spread spectrum encoding

We advocate the use of a novel compressed sensing technique for accelerating the magnetic resonance image acquisition process, coined spread spectrum MR imaging or simply s2MRI. The method resides in pre-modulating the signal of interest by a linear chirp, resulting from the application of quadratic phase profiles, before random k-space under-sampling with uniform average density. The effectiveness of the procedure is theoretically underpinned by the optimization of the coherence between the sparsity and sensing bases. The application of the technique for single coil acquisitions is thoroughly studied by means of numerical simulations as well as phantom and in vivo experiments on a 7T scanner. The corresponding results suggest a favorable comparison with state-of-the-art variable density k-space under-sampling approaches.

Imaging of human leukemic T-cell xenografts in nude mice by radiolabeled monoclonal antibodies and F(ab')2 fragments.

Monoclonal antibodies (MoAb) that react with the T-lymphocyte markers called cluster of differentiation CD5 and CD2 were labeled with iodine 131 (131I) and were injected intravenously in nude mice bearing solid subcutaneous xenografts derived from the human T-cell leukemia line Ichikawa. Both MoAb anti-CD5 and anti-CD2 yielded favorable mean tumor to whole-body ratios of 3.8 and 5.1, respectively. These ratios were further increased up to 10.0 for MoAb anti-CD5 and 15.5 for MoAb anti-CD2 by using their F(ab')2 fragments. The tumors could be imaged clearly by external scanning after injection of F(ab')2 fragments from both MoAb. F(ab')2 fragments from MoAb anti-CD2 and of a third MoAb recognizing the clonotypic determinant (Ti) of the antigen receptor expressed by the human T-cell line Jurkat were injected in mice bearing intrasplenic Jurkat xenografts. A selective localization of both fragments in tumor tissue was demonstrated with mean tumor to whole-body ratios of 7.5 and 4.1 for MoAb anti-CD2 and anti-Ti, respectively. These in vivo experimental results may provide useful information for the potential use of radiolabeled MoAb and fragments in the diagnosis and treatment of patients with T-cell lymphoma and different other forms of T-cell malignancies.

Il Discorso dell'amore verso la patria (1631) di Ludovico Zuccolo

Scopo di questo studio è la disamina e la divulgazione dei pregi letterari e del valore concettualmente innovativo del Discorso dell 'amore verso la patria di Ludovico Zuccolo. L'analisi dei contenuti dell'opera, unitamente alla puntualizzazione delle sue caratteristiche formali e stilistiche, permette di vedere come questo scrittore proponga, utilizzando la forma letteraria del discorso politico, una riuscita codificazione della tematica dei diritti e dei doveri dei cittadini verso la patria; operazione in cui si sostanzia, a mio avviso, l'apporto innovativo dello Zuccolo. Dopo l'iniziale riscoperta, da parte di Benedetto Croce, del capitolo delle Considerazioni sulla Ragion di Stato, l`opera dello Zuccolo ha generato un certo interesse critico fra gli studiosi di letteratura politica del "900" senza tuttavia divenire oggetto di contributi esaustivi malgrado, a nostro parere, la presenza di elementi di originalità di pensiero nel Discorso dell 'amore verso la patria. Inoltre, l'opinione degli specialisti non è mai stata unanime riguardo al valore e ai contenuti delle opere di questo autore. Se per il Croce, ne << La Critica >> del 1926, egli appare come colui che ha prodotto, «Lo scritto più acuto e originale sull'argomento [della Ragion di Stato], composto in quel seco1o.>> (p. 301), per altri egli si presenta come un dotto estensore di trattati politici nei quali sfoggia abilmente la sua erudizione classica e Luigi Firpo arriva a suggerire addirittura che lo Zuccolo sia colpevole di plagio proprio laddove tratta il tema della Ragion di Stato : Al punto in cui siamo, una cosa è certa, e cioè che i conti non tornano : non riesco a credere che uno scrittore inzeppi centinaia e centinaia di pagine di luoghi comuni, di erudizione d"accatto, di oziosità accademiche, e poi un bel mattino, morso dalla tarantola o baciato in fronte da Minerva, metta in carta il piccolo capolavoro, le pagine meditate e profonde, e perciò lungamente soffeite, che pure gli appartengono per una paternità incontestata e certa. Dico questo, perché in un caso del genere, non al miracolo s"avrebbe da credere, ma, semmai, al plagio. (1). Catherine Pitiot, nel suo saggio La retorica politica nell 'opera utopica di Ludovico Zuccolo, coglie invece in questo autore unicamente l"utopista che << lntende allontanarsi dalla realtà contemporanea per modificarla, correggerla e presentare un'in1magine che sia fondamentalmente diversa, a livello strutturale. >> (2). Di parere diametralmente opposto Rodolfo de Mattei, che attribuisce allo Zuccolo lo status di anti-utopista per eccellenza, tipico di uno scrittore che, Non ha voluto usufruire della facile libertà della fantasia per sovvertire l'ordine storico e per alterare arbitrariamente la natura umana, cioé per proporre un ordinamento mirante ad una radicale trasformazione della società e quindi di assai dubbia realizzazione. (3). Altri studiosi, fra cui Bruno Nediani, si sono dedicati alla descrizione della personalità dello Zuccolo, attingendo alle sue lettere - che lo stesso Nediani ha riscoperto - oltre che ai brevi accermi che di sé fa lo Zuccolo negli scritti. Dal saggio del Nediani, La personalità di Ludovico Zuccolo (1969), emerge la figura di un uomo tormentato e insoddisfatto, ossessionato dal sospetto dell"autorità ecclesiastica, costretto a procacciarsi impieghi inadeguati presso i potenti, all'inseguimento dell'obiettivo di una carriera che, comunque, finisce con il risultargli sempre, prima o poi, insopportabile. Più recentemente, Sergio Bertelli, nel suo contributo alla Storia della letteratura di Cecchi e Sapegno, ha aperto una nuova prospettiva sullo Zuccolo proponendolo come colui che, Spezza finalmente il cerchio moralistico costruito dal Botero attorno al pensiero machiavelliano e la ragion di stato cessa di essere giudicata vera o falsa, buona o malvagia, interessando in sé e per sé, cioé nei suoi presupposti e nei suoi fini esclusivamente politici. (4).

Al di là del fiume - attraverso il fiume: il basso corso del Ter in Catalogna

La ricerca prende in considerazione dal punto di vista dell’architettura e dell’urbanistica la relazione tra la città e il fiume che la attraversa o la lambisce; l’insediamento umano viene analizzato nel contesto del bacino idrografico al quale appartiene. La ricerca è stata sviluppata in seno alla tesi dottorale ora in fase di elaborazione presso il Departamento de Urbanismo y Ordenación del Territorio dell’Universidad Politecnica de Catalunya. La tesi ha come caso studio il tratto basso del fiume Ter in Catalogna. Nella discussione sul paesaggio urbano contemporaneo oggi la riflessione è centrata sulla città che si territorializza; la dimensione urbana interferisce con gran parte della superficie della terra facendo sfumare le tradizionali distinzioni tra urbano e non-urbano, tra spazio costruito e spazio aperto. In questo contesto, quale termine di conciliazione tra la dinamica naturale e la costruzione storica dei luoghi prodotta dall’intervento umano, il fiume si rivela uno strumento essenziale di analisi e progetto. L’obiettivo di questa ricerca è suggerire un’approssimazione al progetto della città che si sviluppa lungo il corso fluviale costruendo strumenti per la riflessione “attraverso il fiume”. Partendo dall’ipotesi che la città si insedia lungo un corso d’acqua secondo una sintassi territoriale stabilita dalla geografía e dalla geomorfologia del fiume stesso, il fine è fornire strumenti per il processo di recupero degli spazi fluviali in contesti urbanizzati. Il fiume diviene componente geografica chiave degli insediamenti dispersi e risorsa per costruirne l’abitabilità.

Scimitar Syndrome in an Asymptomatic Adult: Fortuitous Diagnosis by Imaging Technique

Congenital cardiopathies in adults are a rare clinical entity in the cardiology consultations. Advances in imaging techniques allow the fortuitous diagnosis of mild forms of these congenital abnormalities. We describe a case of an asymptomatic 41-year-old man, with a medical history of recurrent pneumonia during childhood and an established diagnosis of scimitar syndrome by computed tomography.

SLAM using an Imaging Sonar for Partially Structured Underwater Environments

In this paper we describe a system for underwater navigation with AUVs in partially structured environments, such as dams, ports or marine platforms. An imaging sonar is used to obtain information about the location of planar structures present in such environments. This information is incorporated into a feature-based SLAM algorithm in a two step process: (I) the full 360deg sonar scan is undistorted (to compensate for vehicle motion), thresholded and segmented to determine which measurements correspond to planar environment features and which should be ignored; and (2) SLAM proceeds once the data association is obtained: both the vehicle motion and the measurements whose correct association has been previously determined are incorporated in the SLAM algorithm. This two step delayed SLAM process allows to robustly determine the feature and vehicle locations in the presence of large amounts of spurious or unrelated measurements that might correspond to boats, rocks, etc. Preliminary experiments show the viability of the proposed approach

Coronary MR imaging using free-breathing 3D steady-state free precession with radial k-space sampling.

PURPOSE: To investigate the potential of free-breathing 3D steady-state free precession (SSFP) imaging with radial k-space sampling for coronary MR-angiography (MRA), coronary projection MR-angiography and coronary vessel wall imaging. MATERIALS AND METHODS: A navigator-gated free-breathing T2-prepared 3D SSFP sequence (TR = 6.1 ms, TE = 3.0 ms, flip angle = 120 degrees, field-of-view = 360 mm(2)) with radial k-space sampling (384 radials) was implemented for coronary MRA. For projection coronary MRA, this sequence was combined with a 2D selective aortic spin tagging pulse. Coronary vessel wall imaging was performed using a high-resolution inversion-recovery black-blood 3D radial SSFP sequence (384 radials, TR = 5.3 ms, TE = 2.7 ms, flip angle = 55 degrees, reconstructed resolution 0.35 x 0.35 x 1.2 mm(3)) and a local re-inversion pulse. Six healthy volunteers (two for each sequence) were investigated. Motion artifact level was assessed by two radiologists. Results: In coronary MRA, the coronary lumen was displayed with a high signal and high contrast to the surrounding lumen. Projection coronary MRA demonstrated selective visualization of the coronary lumen while surrounding tissue was almost completely suppressed. In coronary vessel wall imaging, the vessel wall was displayed with a high signal when compared to the blood pool and the surrounding tissue. No visible motion artifacts were seen. Conclusion: 3D radial SSFP imaging enables coronary MRA, coronary projection MRA and coronary vessel wall imaging with a low motion artifact level.

Serum sCD163 levels are associated with type 2 diabetes mellitus and are influenced by coffee and wine consumption: results of the Di@bet.es study.

OBJECTIVE Serum levels of soluble TNF-like weak inducer of apoptosis (sTWEAK) and its scavenger receptor CD163 (sCD163) have been linked to insulin resistance. We analysed the usefulness of these cytokines as biomarkers of type 2 diabetes in a Spanish cohort, together with their relationship to food consumption in the setting of the Di@bet.es study. RESEARCH DESIGN AND METHODS This is a cross-sectional, matched case-control study of 514 type 2 diabetes subjects and 517 controls with a Normal Oral Glucose Tolerance Test (NOGTT), using data from the Di@bet.es study. Study variables included clinical and demographic structured survey, food frequency questionnaire and physical examination. Serum concentrations of sTWEAK and sCD163 were measured by ELISA. Linear regression analysis determined which variables were related to sTWEAK and sCD163 levels. Logistic regression analysis was used to estimate odd ratios of presenting type 2 diabetes. RESULTS sCD163 concentrations and sCD163/sTWEAK ratio were 11.0% and 15.0% higher, respectively, (P<0.001) in type 2 diabetes than in controls. Following adjustment for various confounders, the OR for presenting type 2 diabetes in subjects in the highest vs the lowest tertile of sCD163 was [(OR), 2,01 (95%CI, 1,46-2,97); P for trend <0.001]. Coffee and red wine consumption was negatively associated with serum levels of sCD163 (P = 0.0001 and; P = 0.002 for coffee and red wine intake, respectively). CONCLUSIONS High circulating levels of sCD163 are associated with type 2 diabetes in the Spanish population. The association between coffee and red wine intake and these biomarkers deserves further study to confirm its potential role in type 2 diabetes.

Diffusion spectrum magnetic resonance imaging (DSI) tractography of crossing fibers.

MRI tractography is the mapping of neural fiber pathways based on diffusion MRI of tissue diffusion anisotropy. Tractography based on diffusion tensor imaging (DTI) cannot directly image multiple fiber orientations within a single voxel. To address this limitation, diffusion spectrum MRI (DSI) and related methods were developed to image complex distributions of intravoxel fiber orientation. Here we demonstrate that tractography based on DSI has the capacity to image crossing fibers in neural tissue. DSI was performed in formalin-fixed brains of adult macaque and in the brains of healthy human subjects. Fiber tract solutions were constructed by a streamline procedure, following directions of maximum diffusion at every point, and analyzed in an interactive visualization environment (TrackVis). We report that DSI tractography accurately shows the known anatomic fiber crossings in optic chiasm, centrum semiovale, and brainstem; fiber intersections in gray matter, including cerebellar folia and the caudate nucleus; and radial fiber architecture in cerebral cortex. In contrast, none of these examples of fiber crossing and complex structure was identified by DTI analysis of the same data sets. These findings indicate that DSI tractography is able to image crossing fibers in neural tissue, an essential step toward non-invasive imaging of connectional neuroanatomy.