Surgicel-Related Uptake on Positron Emission Tomography Scan Mimicking Prosthetic Valve Endocarditis.

A 78-year-old patient who underwent an aortic valve replacement presented 6 months later with clinical symptoms suspicious for prosthetic valve endocarditis. Echocardiography showed no features suggestive of endocarditis, but a positron emission tomography/computed tomography with fluorine-18-fluorodeoxyglucose (F-FDG PET/CT) scan showed an area of hyper-uptake around the ascending aorta. We realized that the sheet of Surgicel (Ethicon, Bridgewater, NJ) hemostat had been placed over the aortotomy suture line at the time of surgery.

Variable Thickness in Plates-A Solution for SHM Based on the Topological Derivative.

The topological derivative tool is applied here in structural health monitoring (SHM) problems to locate small defects in a material plate with complex geometry that is subject to permanent multifrequency guided waves excitation. Compared to more standard SHM methods, based in measuring the time-lag between emitted and received propagative pulses plus some postprocessing, the topological derivative somehow compares the measured and computed (solving the full elasto-dynamic equations) response of the damaged plate, instead of relying on only the time of flight of the wave. Thus, the method profits the knowledge behind the physics of the problem and can cope with scenarios in which classical methods give poor results.