Randomized Trial of Pacemaker and Lead System for Safe Scanning at 1.5 Tesla

BackgroundMagnetic resonance imaging (MRI) of pacemakers is a relative contraindication because of the risks to the patient from potentially hazardous interactions between the MRI and the pacemaker system. Chest scans (ie, cardiac magnetic resonance scans) are of particular importance and higher risk. The previously Food and Drug Administration-approved magnetic resonance conditional system includes positioning restrictions, limiting the powerful utility of MRI.ObjectiveTo confirm the safety and effectiveness of a pacemaker system designed for safe whole body MRI without MRI scan positioning restrictions.MethodsPrimary eligibility criteria included standard dual-chamber pacing indications. Patients (n = 263) were randomized in a 2:1 ratio to undergo 16 chest and head scans at 1.5 T between 9 and 12 weeks postimplant (n = 177) or to not undergo MRI (n = 86) post-implant. Evaluation of the pacemaker system occurred immediately before, during (monitoring), and after MRI, 1-week post-MRI, and 1-month post-MRI, and similarly for controls. Primary end points measured the MRI-related complication-free rate for safety and compared pacing capture threshold between MRI and control subjects for effectiveness.ResultsThere were no MRI-related complications during or after MRI in subjects undergoing MRI (n = 148). Differences in pacing capture threshold values from pre-MRI to 1-month post-MRI were minimal and similar between the MRI and control groups.ConclusionsThis randomized trial demonstrates that the Advisa MRI pulse generator and CapSureFix MRI 5086MRI lead system is safe and effective in the 1.5 T MRI environment without positioning restrictions for MRI scans or limitations of body parts scanned

Edge emitting quantum cascade microlasers on InP with deeply etched one-dimensional photonic crystals

Edge emitting quantum cascade microlasers based on InP have been fabricated and investigated. Deeply etched Bragg mirrors have been manufactured at the end of the resonators, to reduce the mirror losses of short cavity devices. In order to achieve the required high aspect ratio, an optimized plasma dry etching process has been developed, which allows monolithic device fabrication in a single dry etching step. The short resonator length results in a large Fabry-Perot mode spacing, which leads to a single mode operation. A side mode suppression ratio of about 20 dB at 80 K has been observed. (c) 2007 American Institute of Physics.</p

Diodes Laser à puits quantiques de Type I pour Analyse de Gaz Emettant à 3,3 µm à Température Ambiante”

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Mid infrared interband cascade lasers for sensing applications

The growth of Interband Cascade Laser material to cover the wavelength range from 3-4 mu m is presented along with the fabrication and characterization of Broad Area (BA) and Ridge Waveguide (RWG) devices based on this material. Pulsed operation slightly below room temperature is observed for both device types, and a strong reduction of threshold currents can be observed in the RWG lasers. Variation of the active Quantum Well width in the epitaxial structures enables laser emission in the 3-4 mu m wavelength region.</p

Type I quantum well Laser Diodes for Gas Sensing Emitting at 3.3 µm at Room Temperature

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