A comparison between in vivo and ex vivo HR-MAS H-1 MR spectra of a pediatric posterior fossa lesion

The present case report was aimed at identifying the molecular profile characteristic of a primitive neuroectodermal tumor (PNET) in a 3-year-old child affected by a lesion localized in the cerebellar region. The histological diagnosis was medulloblastoma. In vivo single voxel H-1 magnetic resonance spectroscopy (MRS) shows high specificity in detecting the main metabolic alterations in the primitive cerebellar lesion; a very high amount of the choline-containing compounds and very low level of creatine derivatives and N-acetylaspartate. Ex vivo high resolution magic angle spinning (HR-MAS) H-1 magnetic resonance spectroscopy, performed at 9.4 Tesla on the neoplastic specimen collected during surgery, allows for the unambiguous identification of several metabolites giving a more in-depth evaluation of the metabolic pattern of the lesion. The ex vivo HR-MAS MR spectra show that the spectral detail is much higher than that obtained in vivo and that, for example, myo-inositol, taurine and phosphorylethanolamine contribute to the in vivo signal at 3.2 ppm, usually attributed to choline-containing compounds. In addition, the spectroscopic data appear to correlate with some morphological features of the medulloblastoma. Consequently, the present study shows that ex vivo HR-MAS H-1 MRS is able to strongly improve the clinical possibility of in vivo MRS and can be used in conjunction with in vivo spectroscopy for clinical purposes

The impact of transfer learning on 3D deep learning convolutional neural network segmentation of the hippocampus in mild cognitive impairment and Alzheimer disease subjects

Research on segmentation of the hippocampus in magnetic resonance images through deep learning convolutional neural networks (CNNs) shows promising results, suggesting that these methods can identify small structural abnormalities of the hippocampus, which are among the earliest and most frequent brain changes associated with Alzheimer disease (AD). However, CNNs typically achieve the highest accuracy on datasets acquired from the same domain as the training dataset. Transfer learning allows domain adaptation through further training on a limited dataset. In this study, we applied transfer learning on a network called spatial warping network segmentation (SWANS), developed and trained in a previous study. We used MR images of patients with clinical diagnoses of mild cognitive impairment (MCI) and AD, segmented by two different raters. By using transfer learning techniques, we developed four new models, using different training methods. Testing was performed using 26% of the original dataset, which was excluded from training as a hold-out test set. In addition, 10% of the overall training dataset was used as a hold-out validation set. Results showed that all the new models achieved better hippocampal segmentation quality than the baseline SWANS model (ps <.001), with high similarity to the manual segmentations (mean dice [best model] = 0.878 ± 0.003). The best model was chosen based on visual assessment and volume percentage error (VPE). The increased precision in estimating hippocampal volumes allows the detection of small hippocampal abnormalities already present in the MCI phase (SD = [3.9 ± 0.6]%), which may be crucial for early diagnosis

Consistency conditions and trace anomalies in six dimensions

Conformally invariant quantum field theories develop trace anomalies when defined on curved backgrounds. We study again the problem of identifying all possible trace anomalies in d=6 by studying the consistency conditions to derive their 10 independent solutions. It is known that only 4 of these solutions represent true anomalies, classified as one type A anomaly, given by the topological Euler density, and three type B anomalies, made up by three independent Weyl invariants. However, we also present the explicit expressions of the remaining 6 trivial anomalies, namely those that can be obtained by the Weyl variation of local functionals. The knowledge of the latter is in general necessary to disentangle the universal coefficients of the type A and B anomalies from calculations performed on concrete models.Comment: 16 pages, LaTe

Valori ematici di riferimento in suini in accrescimento ingrasso

L'esperienza è stata condotta su suini Dx(LxLW), dai quali ogni 5 settimane è stato prelevato il sangue, tramite venoject dalla vena giugulare, dopo un digiuno di 8 ore. I 128 casi validi ottenuti per ciascun parametro sono stati utilizzati per l'individuazione dei limiti di riferimento definiti dai 2,5 ai 97,5 frattili applicando il metodo parametrico

Humor comprehension and appreciation: an fMRI study

Humor is a unique ability in human beings. Suls [A two-stage model for the appreciation of jokes and cartoons. In P. E. Goldstein & J. H. McGhee (Eds.), The psychology of humour. Theoretical perspectives and empirical issues. New York: Academic Press, 1972, pp. 81-100] proposed a two-stage model of humor: detection and resolution of incongruity. Incongruity is generated when a prediction is not confirmed in the final part of a story. To comprehend humor, it is necessary to revisit the story, transforming an incongruous situation into a funny, congruous one. Patient and neuroimaging studies carried out until now lead to different outcomes. In particular, patient studies found that right brain-lesion patients have difficulties in humor comprehension, whereas neuroimaging studies suggested a major involvement of the left hemisphere in both humor detection and comprehension. To prevent activation of the left hemisphere due to language processing, we devised a nonverbal task comprising cartoon pairs. our findings demonstrate activation of both the left and the right hemispheres when comparing funny versus nonfunny cartoons. In particular, we found activation of the right inferior frontal gyrus (BA 47), the left superior temporal gyrus (BA 38), the left middle temporal gyrus (BA 21), and the left cerebellum. These areas were also activated in a nonverbal task exploring attribution of intention [Brunet, E., Sarfati, Y., Hardy-Bayle, M. C., & Decety, J. A PET investigation of the attribution of intentions with a nonverbal task. Neuroimage, 11, 157-166, 2000]. We hypothesize that the resolution of incongruity might occur through a process of intention attribution. We also asked subjects to rate the funniness of each cartoon pair. A parametric analysis showed that the left amygdala was activated in relation to subjective amusement. We hypothesize that the amygdala plays a key role in giving humor an emotional dimension