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Objective: Normal interictal [18F]FDG‐PET can be predicted from the corresponding T1w MRI with Generative Adversarial Networks (GANs). A technique we call SIPCOM (Subtraction Interictal PET Co‐registered to MRI) can then be used to compare epilepsy patients' predicted and clinical PET. We assessed the ability of SIPCOM to identify the Resection Zone (RZ) in patients with drug‐resistant epilepsy (DRE) with reference to visual and statistical parametric mapping (SPM) analysis. Methods: Patients with complete presurgical work‐up and subsequent SEEG and cortectomy were included. RZ localisation, the reference region, was assigned to one of eighteen anatomical brain regions. SIPCOM was implemented using healthy controls to train a GAN. To compare, the clinical PET coregistered to MRI was visually assessed by two trained readers, and a standard SPM analysis was performed. Results: Twenty patients aged 17‐50 (32 ± 7.8) years were included, 14 (70%) with temporal lobe epilepsy (TLE). Eight (40%) were MRI‐negative. After surgery, 14 patients (70%) had a good outcome (Engel I‐II). RZ localisation rate was 60% with SIPCOM vs 35% using SPM (P = 0.015) and vs 85% using visual analysis (P = 0.54). Results were similar for Engel I‐II patients, the RZ localisation rate was 64% with SIPCOM vs 36% with SPM. With SIPCOM localisation was correct in 67% in MRI‐positive vs 50% in MRI‐negative patients, and 64% in TLE vs 43% in extra‐TLE. The average number of false‐positive clusters was 2.2 ± 1.3 using SIPCOM vs 2.3 ± 3.1 using SPM. All RZs localized with SPM were correctly localized with SIPCOM. In one case, PET and MRI were visually reported as negative, but both SIPCOM and SPM localized the RZ. Significance: SIPCOM performed better than the reference computer‐assisted method (SPM) for RZ detection in a group of operated DRE patients. SIPCOM's impact on epilepsy management needs to be prospectively validated. [ABSTRACT FROM AUTHOR]

The commensal rodent Mastomys natalensis is the natural reservoir of Lassa arenavirus (LASV), which causes hemorrhagic fever in West Africa. To study a possible effect of the virus on phenotypic and genotypic variation of its persistently infected host, we compared LASV-positive and non-infected wild-caught M. natalensis. The LASV effects on the phenotypic variation were explored using standard external morphometric measurements, geometric morphometric analyses of the cranial size and shape, and brain case volume. The genetic variability of M. natalensis specimens was assessed using 9 polymorphic microsatellite markers. Independent of sex and age, LASV-infected animals had smaller external body measurements, reproductive organs, skull size and brain case volume. Cranial shape differences between the 2 groups are represented by a lateral constriction of the entire skull. The genetic variability revealed consanguinity only among the LASV-positive rodents. We hypothesize that growth impairment may result in a selective disadvantage for LASV-infected M. natalensis, leading to a preferably commensal lifestyle in areas where the LAVS is endemic and, thereby, increasing the risk of LASV transmission to humans. [ABSTRACT FROM AUTHOR]

Purpose: To identify MRI biomarkers that could be used to follow disease progression and therapeutic efficacy in one individual muscle in patients with myotonic dystrophy type 1 (DM1). Materials and Methods: Lower limb MRI and maximal ankle dorsiflexor strength assessment, using a hand-held dynamometer, were performed in 19 DM1 patients and 6 control subjects. The volume of residual muscle tissue of Tibialis Anterior (TA) muscle was chosen as an index for muscle atrophy, and the T2-relaxation-time of the residual muscle tissue was measured to evaluate edema-like lesions. The fat-to-water ratio was assessed using three-point Dixon images to quantify fat infiltration in the entire muscle. Results: The intra-observer variability of MRI indices (∼5.2% for the residual muscle tissue volume and 2.5% for the fat-to-water ratio) was lower than that of the dorsiflexor torque measurement (∼11.5%). A high correlation (r = 0.91) was found between maximal ankle dorsiflexor strength and residual TA muscle tissue volume in DM1 patients. Increases in the fat-to-water ratio and T2-relaxation-time were associated with a decrease in maximal ankle dorsiflexor strength. Conclusion: MRI appears as a noninvasive method which can be used to follow disease progression and therapeutic efficacy. J. Magn. Reson. Imaging 2012;35:678-685. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Zebrafish embryo is a well-established model used in many fields of modern experimental biology. We demonstrate that it provides a promising model platform for exploring fundamental MR aspects that can be used to screen and study active MR molecules before progressing to more complex living systems. Setting up a dedicated MRI methodology, we arrayed a large number of living embryos, which were microinjected at very early stages of development with different contrast agents. We also showed that MRI signal intensity correlates with the gadolinium content of zebrafish embryos. This allowed us to validate a new approach for MR compound screening. Using a specific surface coil of 5 mm inner diameter, we obtained for the first time high-spatial-resolution images at 7 T of living zebrafish embryos with a 47 µm isotropic voxel size with an acquisition time of 39 min. Finally, we discuss potential applications of this development: a viable in vivo assay for screening small pharmacological compounds; assessment of and tracking the action of molecules over time. Exploring in vivo biological activity, gene function analysis, and detailed characterization of disease processes in fish are natural extensions of these preliminary studies. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ECG-gated cardiac MRI in the mouse is hindered by many technical difficulties in ECG signal recording inside high magnetic field scanners. The present study proposes a robust rectilinear method of acquiring cardiac and respiratory self-gated cine images in mouse hearts. In this approach, a motion-synchronization MR signal is collected in the center of k-space simultaneously with imaging data in each readout of a nontriggered rectilinear acquisition. This signal is then used for both cardiac and respiratory retrospective gating before cine image reconstruction. The value of this approach for overcoming ECG-gating failure was demonstrated by performing cardiac imaging in eight mice with myocardial infarction. Comparison with an auto-gated radial k-space sampling technique, previously reported for cardiac applications in the mouse, found the rectilinear strategy more robust, thanks to a more reliable self-gating signal, while the radial strategy was less sensitive to motion and flow artifacts. Magn Reson Med 58:745-753, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator-activated receptors (PPARs) are a potential target for neuroprotection in focal ischemic stroke. These nuclear receptors have major effects in lipid metabolism, but they are also involved in inflammatory processes. Three PPAR isotypes have been identified: α, β (or δ) and γ. The development of PPAR transgenic mice offers a promising tool for prospective therapeutic studies. This study used MRI to assess the role of PPAR α and PPAR β in the development of stroke. Permanent middle cerebral artery occlusion induced focal ischemia in wild-type, PPAR α-null mice and PPAR β-null mice. T2-weighted MRI was performed with a 7 T MRI scan on day 0, 1, 3, 7 and 14 to monitor lesion growth in the various genotypes. General Linear Model statistical analysis found a significant difference in lesion volume between wild-type and PPAR-null mice for both α and β isotypes. These data validate high-resolution MRI for monitoring cerebral ischemic lesions, and confirm the neuroprotective role of PPAR α and PPAR β in the brain. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ECG-gated cardiac MRI in the mouse is hindered by many technical difficulties in ECG signal recording inside static and variable high magnetic scanner fields. The present study proposes an alternative robust method of acquiring auto-gated cardiac and respiratory cine images in mouse heart. In our approach, a motion synchronization signal is extracted from the echo peak MR signal of a non-triggered radial acquisition. This signal is then used for both cardiac and respiratory retrospective gating before cine image reconstruction. Highly asymmetric echoes were acquired to achieve the radial k-space sampling in order to avoid radial acquisition related artifacts and to increase auto-gating robustness. In vivo experiments demonstrated the feasibility and robustness of self-gated cine-MRI in the mouse heart at 7T. The signal-to-noise and contrast-to-noise ratios of the self-gated and ECG-gated images were comparable, all parameters being equal. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate color- and spectral Doppler ultrasound in the establishment of normal functional cardiovascular development features in the mouse fetus. Mouse fetuses ( 129Sv strain) were studied in utero between embryonic day (EDs) 9.5 and 19.5. Time–velocity curves were derived from Doppler interrogation of the aorta and umbilical artery. The sample volume was accurately placed on the vessels of interest based on color-Doppler images. From these curves, the following parameters were obtained: heart rate (HR), acceleration time (AT), and deceleration time (DT). HR increased between EDs 9.5 and 19.5 from 102.9 to 303.2 b.p.m. For the other parameters, the most significant change observed was the increase of DT in the umbilical artery at the end of pregnancy, corresponding to the appearance of a diastolic flow. We report the use of a commercially available, clinical, ultrasound unit to obtain quantitative data on the cardiovascular development in the mouse fetus. These results may be useful for the recognition of in utero cardiovascular dysfunction in transgenic or knock-out fetus. [ABSTRACT FROM AUTHOR]

NMR In Biomedicine: MRI monitoring of focal cerebral ischemia in peroxisome proliferator-activated receptor (PPAR)-deficient mice. Jean-Baptiste Pialat, Tae-Hee Chao, Olivier Beuf, Elisabeth Joye, Samir Moucharaffie, Jean-Baptiste Langlois, Chantal Nemoz, Marc Janier, Yves Berthezene, Norbert Nighoghossian, Béatrice Desvergnre and Marlene Wiart. Published online April 24 2007, Issue 20:3, pp. 335-342; DOI: . Following publication it has been noted that an author's name was misspelt. As above, the author was spelt as 'Samir Moucharaffie'. It should have been spelt as 'Samir Moucharrafie'. [ABSTRACT FROM AUTHOR]