Search

Purpose: To design and implement a multi-coil (MC) array for B 0 field generation for image encoding and simultaneous advanced shimming in a novel 1.5T head-only MRI scanner., Methods: A 31-channel MC array was designed following the unique constraints of this scanner design: The vertically oriented magnet is very short, stopping shortly above the shoulders of a sitting subject, and includes a window for the subject to see through. Key characteristics of the MC hardware, the B 0 field generation capabilities, and thermal behavior, were optimized in simulations prior to its construction. The unit was characterized via bench testing. B 0 field generation capabilities were validated on a human 4T MR scanner by analysis of experimental B 0 fields and by comparing images for several MRI sequences acquired with the MC array to those acquired with the system's linear gradients., Results: The MC system was designed to produce a multitude of linear and nonlinear magnetic fields including linear gradients of up to 10 kHz/cm (23.5 mT/m) with MC currents of 5 A per channel. With water cooling it can be driven with a duty cycle of up to 74% and ramp times of 500 μs. MR imaging experiments encoded with the developed multi-coil hardware were largely artifact-free; residual imperfections were predictable, and correctable., Conclusion: The presented compact multi-coil array is capable of generating image encoding fields with amplitudes and quality comparable to clinical systems at very high duty cycles, while additionally enabling high-order B 0 shimming capabilities and the potential for nonlinear encoding fields., (© 2023 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Prenatal exposure to valproic acid (VA) is associated with an increased risk of congenital malformations, especially limb defects like radial ray defects. Tibial developmental field defect in VA embryopathy remains exceptional. We report on three patients presenting with tibial hypo/aplasia associated with either femoral bifurcation or radial ray defect following prenatal exposure to VA. Femoral bifurcation and tibial agenesis has been described in the Gollop-Wolfgang complex and in the tibial agenesis-ectrodactyly syndrome. Tibial agenesis has also been reported in VACTERL association. The relation between prenatal exposure to VA and tibial agenesis is discussed., (© 2010 Wiley-Liss, Inc.)

Subgaleal hematoma in the newborn infant is rare, occurs early, and often bears serious consequences. We report on 2 subacute cases of bruising of the scalp that occurred following the use of a suction cup. Emergency treatment consisted of a transfusion of packed red blood cells and fresh frozen plasma. Children born by use of vacuum extractor or forceps require careful monitoring by the nursing staff throughout their stay in the maternity unit., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Background: In 2005-2006 Reunion Island experienced a massive outbreak of chikungunya, a mosquito-borne alphavirus infection. During this epidemic, early neonatal cases were observed with a highly probable mother-to-child transmission., Methods: A retrospective descriptive study was conducted in 5 neonatal medicine departments. Chikungunya virus infection was confirmed by reverse transcription-polymerase chain reaction or specific serology in mothers and their newborns. Mothers were screened if they presented signs at delivery or if their neonates became ill on the first days of life., Results: Thirty-eight neonates were enrolled. All mothers, except 2 asymptomatic mothers, presented signs during the perinatal period (range, day(D) -4 to D+1). All neonates were symptomatic and presented symptoms on D3 to D7 (mean, D4). The mean interval between onset of maternal illness and onset of neonatal illness was 5 days (range, 3-9). The most frequent clinical signs in neonates were fever (79%), pain (100%), rash (82%), and peripheral edema (58%). Thrombocytopenia (76%), lymphopenia (47%), decreased prothrombin value (65%), and elevation of aspartate aminotransferase (77%) were detected. Complications included seizures (6), hemorrhagic syndrome (6), and hemodynamic disorders (10). Reverse transcription-polymerase chain reaction in cerebrospinal fluid was positive in 22 of 24 cases, and abnormal findings on brain magnetic resonance imaging (14 of 25) with white matter lesions or intraparenchymal hemorrhages or both were found. Echocardiography (16) showed myocardial hypertrophy (5), ventricular dysfunction (2), pericarditis (2), and coronary artery dilatation (6). One neonate died of necrotizing enterocolitis., Conclusions: The chikungunya epidemic that occurred on La Reunion Island revealed for the first time the possibility of mother-to-child transmission in the perinatal period with a high rate of morbidity.