Purpose
Popliteal artery aneurysms (PAAs) are a rare condition with an incidence <0.1%. The objective of this study was to evaluate the effectiveness of endovascular treatment of PAA with a covered ...stent-graft.
Materials and methods
Between January 2009 and July 2010, ten patients (nine men and one woman, mean age 69±12 years) with PAA were treated by endovascular placement of a heparin-coated stent-graft. All procedures were evaluated in terms of technical success, patency at 1, 6 and 12 months as assessed by colour Doppler ultrasound, complications, procedure duration and length of postoperative hospital stay.
Results
We obtained 100% technical success, with no peri- or postprocedural complications. Average duration of the procedure was 40 min, and mean hospital stay was 3 days. Primary and secondary patency rates at 1, 6 and 12 months were 100% and 100%, 90% and 100%, and 90% and 100%, respectively. Only one case of endoleak occurred.
Discussion
In keeping with the literature, our study demonstrates the effectiveness of endovascular repair of PAA, with short- and mid-term patency rates comparable to those of open surgery. Larger series and longer follow-up periods are needed to confirm these preliminary results.
Sonotubometry allows an assessment of the Eustachian tube (ET) function under physiological conditions. The reliability of the application of an 8 kHz pure-tone signal was investigated. In 40 normal ...subjects (80 ears) sonotubometric studies were performed with a custom-made device. ET opening was provoked by swallowing, yawning and Valsalva manoeuvre. An opening was detected in all patients but not in all manoeuvres. Four characteristic sonotubogram types were found. Most common was the spike-type (60%). The double-peak and the plateau-shaped curves occurred in 17% each. The finding of an descendant curve was rare (5%). Of 623 measurements, only in 55% manouvres a positive sonotubometric result was found despite the fact that the patients reported an opening in all cases. The median opening time in dry swallowing, liquid swallowing, yawning and Valsalva was found to be 486, 355, 1,263 and 1,250 ms. A median sound increase of 16.0, 13.8, 15.0 and 15.0 dB was recorded for these manoeuvres. There was a statistic significant difference (P < 0.02) between the increase in sound intensity of liquid and dry swallowing. There was also a statistic significant difference found for the duration of the forced manoeuvres Valsalva and yawning as compared to dry and liquid swallowing (P < 0.0001). The use of an 8 kHz pure-tone signal showed a limited sensitivity for the detection of ET openings. This is mainly due to noise pollution, but also because of an altered positioning and/or dislocation of the probes and compression of the nostrils. The application of an 8 kHz signal is therefore not reliable enough for the use in practice. Further technical refinements and the use of alternative signals are necessary for a broader clinical application.
To investigate and compare the quantitative accuracy of (90)Y imaging across different generation PET/CT scanners, for the purpose of dosimetry after radioembolization with resin microspheres.
A ...strict experimental and imaging protocol was followed by 47 international sites using the NEMA 2007/IEC 2008 PET body phantom with an 8-to-1 sphere-to-background ratio of (90)Y solution. The phantom was imaged over a 7-day period (activity ranging from 0.5 to 3.0 GBq) and all reconstructed data were analysed at a core laboratory for consistent processing. Quantitative accuracy was assessed through measures of total phantom activity, activity concentration in background and hot spheres, misplaced counts in a nonradioactive insert, and background variability.
Of the 69 scanners assessed, 37 had both time-of-flight (ToF) and resolution recovery (RR) capability. These current generation scanners from GE, Philips and Siemens could reconstruct background concentration measures to within 10% of true values over the evaluated range, with greater deviations on the Philips systems at low count rates, and demonstrated typical partial volume effects on hot sphere recovery, which dominated spheres of diameter <20 mm. For spheres >20 mm in diameter, activity concentrations were consistently underestimated by about 20%. Non-ToF scanners from GE Healthcare and Siemens were capable of producing accurate measures, but with inferior quantitative recovery compared with ToF systems.
Current generation ToF scanners can consistently reconstruct (90)Y activity concentrations, but they underestimate activity concentrations in small structures (≤37 mm diameter) within a warm background due to partial volume effects and constraints of the reconstruction algorithm. At the highest count rates investigated, measures of background concentration (about 300 kBq/ml) could be estimated on average to within 1%, 5% and 2% for GE Healthcare (all-pass filter, RR + ToF), Philips (4i8s ToF) and Siemens (2i21s all-pass filter, RR + ToF) ToF systems, respectively. Over the range of activities investigated, comparable performance between GE Healthcare and Siemens ToF systems suggests suitability for quantitative analysis in a scenario analogous to that of postradioembolization imaging for treatment of liver cancer.
We use particular fuzzy relation equations for compression/decompression of colour images in the RGB and YUV spaces, by comparing the results of the reconstructed images obtained in both cases. Our ...tests are made over well known images of 256x256 pixels (8 bits per pixel in each band) extracted from Corel Gallery. After the decomposition of each image in the three bands of the RGB and YUV colour spaces, the compression is performed using fuzzy relation equations of "min - arrow right t" type, where "t" is the Lukasiewicz t-norm and "arrow right t" is its residuum. Any image is subdivided in blocks and each block is compressed by optimizing a parameter inserted in the Gaussian membership functions of the fuzzy sets, used as coders in the fuzzy equations. The decompression process is realized via a fuzzy relation equation of max-t type. In both RGB and YUV spaces we evaluate and compare the root means square error (RMSE) and the consequent peak signal to noise ratio (PSNR) on the decompressed images with respect to the original image under several compression rates. PUBLICATION ABSTRACT
Conclusions Spatial (fMRI) and spectro-temporal (EEG) activation patterns independently confirm the involvement of parietal (left and right) and right frontal cortex during visual mental imagery and ...suggest an early and crucial role for oscillatory (theta/alpha) responses in central frontal brain structures (SMA).
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