Contrast-enhanced CMR in patients after percutaneous closure of the left atrial appendage: A pilot study

<p>Abstract</p> <p>Background</p> <p>To evaluate the feasibility and value of first-pass contrast-enhanced dynamic and post-contrast 3D CMR in patients after transcatheter occlusion of left atrial appendage (LAA) to identify incorrect placement and persistent leaks.</p> <p>Methods</p> <p>7 patients with different occluder systems (n = 4 PLAATO; n = 2 Watchman; n = 1 ACP) underwent 2 contrast-enhanced (Gd-DOTA) CMR sequences (2D TrueFISP first-pass perfusion and 3D-TurboFLASH) to assess localization, artifact size and potential leaks of the devices. Perfusion CMR was analyzed visually and semi-quantitatively to identify potential leaks.</p> <p>Results</p> <p>All occluders were positioned within the LAA. The ACP occluder presented the most extensive artifact size. Visual assessment revealed a residual perfusion of the LAA apex in 4 cases using first-pass perfusion and 3D-TurboFLASH indicating a suboptimal LAA occlusion.</p> <p>By assessing signal-to-time-curves the cases with a visually detected leak showed a 9-fold higher signal-peak in the LAA apex (567 ± 120% increase from baseline signal) than those without a leak (61 ± 22%; p < 0.03). In contrast, the signal increase in LAA proximal to the occluder showed no difference (leak 481 ± 201% vs. no leak 478 ± 125%; p = 0.48).</p> <p>Conclusion</p> <p>This CMR pilot study provides valuable non-invasive information in patients after transcatheter occlusion of the LAA to identify correct placement and potential leaks. We recommend incorporating CMR in future clinical studies to evaluate new device types.</p

Characterization of past and present solid waste streams from the plutonium finishing plant

During the next two decades the transuranic (TRU) wastes now stored in the burial trenches and storage facilities at the Hanford Site are to be retrieved, processed at the Waste Receiving and Processing (WRAP) Facility, and shipped to the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico for final disposal. Over 50% of the TRU waste to be retrieved for shipment to the WIPP has been generated at the Plutonium Finishing Plant (PFP), also known as the Plutonium Processing and Storage Facility and Z Plant. The purpose of this report is to characterize the radioactive solid wastes generated by the PFP since its construction in 1947 using process knowledge, existing records, and history-obtained from interviews. The PFP is currently operated by Westinghouse Hanford Company (WHC) for the US Department of Energy (DOE)