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Preoperative Evaluation of Posthepatectomy Liver Failure Using MRI-Based Liver Function Indices in Child-Pugh Class A Patient
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作者 Shigeru Matsushima Yozo Sato +7 位作者 Hidekazu Yamaura Mina Kato Yui Onoda shinichi murata Yasuhiro Shimizu Yasutomi Kinosada Hideyuki Nishiofuku Yoshitaka Inaba 《Open Journal of Radiology》 2016年第2期147-156,共10页
Purpose: To evaluate posthepatectomy liver failure (PHLF) using gadoxetic acid-enhanced magnetic resonance imaging (MRI) with a measure of relative liver enhancement (RLE) on hepatobiliary phase images, thereby facili... Purpose: To evaluate posthepatectomy liver failure (PHLF) using gadoxetic acid-enhanced magnetic resonance imaging (MRI) with a measure of relative liver enhancement (RLE) on hepatobiliary phase images, thereby facilitating safe liver resection. Methods: Twenty patients in Child-Pugh class A underwent tumor excision surgery and indocyanine green (ICG) clearance of future remnant liver (FRL) (ICG-Krem) values were >0.05. PHLF was evaluated using the grading system of the International Study Group of Liver Surgery (ISGLS). The RLE value was defined as the signal gain percentage between the precontrast and hepatocellular images. In the whole liver and FRL, theRLE value measured the tumor-free liver parenchyma in RLE images. We examined the correlation between indocyanine green clearance (ICG-K) and MRI-based liver function in the whole liver. Preoperative PHLF evaluation was predicted using remnant hepatocellular uptake index (rHUI), remnant RLE (rRLE), coefficient variation of Rrle [Cv(rRLE)], and ICG-Krem corrected by heterogeneous liver function(HLF-ICG-Krem). Results: HLF-ICG-Krem and rRLE values correlated with INRs after postoperative day five (r = -0.55 and 0.46, p = 0.01 and 0.04, respectively). Furthermore, HLF-ICG-Krem values ≤0.05 detected two patients with higher INRs after postoperative day five. On the other hand, neither rHUI nor Cv(rRLE) was correlated with INRs after postoperative day five (r = 0.28, and -0.03, respectively;p >0.05 for both). HLF-ICG-Krem was significantly lower with PHLF than without PHLF (p = 0.005). Conclusion: HLF-ICG-Krem is useful for evaluating PHLF more correctly. 展开更多
关键词 Posthepatectomy Liver Failure Heterogeneous Liver Function Gadoxetic Acid Relative Liver Enhancement Indocyanine Green Clearance
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Audio Watermarking Using Wavelet Transform and Genetic Algorithm for Realizing High Tolerance to MP3 Compression
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作者 shinichi murata Yasunari Yoshitomi Hiroaki Ishii 《Journal of Information Security》 2011年第3期99-112,共14页
Recently, several digital watermarking techniques have been proposed for hiding data in the frequency domain of audio signals to protect the copyrights. However, little attention has been given to the optimal position... Recently, several digital watermarking techniques have been proposed for hiding data in the frequency domain of audio signals to protect the copyrights. However, little attention has been given to the optimal position in the frequency domain for embedding watermarks. In general, there is a tradeoff between the quality of the watermarked audio and the tolerance of watermarks to signal processing methods, such as compression. In the present study, a watermarking method developed for a visual image by using a wavelet transform was applied to an audio clip. We also improved the performance of both the quality of the watermarked audio and the extraction of watermarks after compression by the MP3 technique. To accomplish this, we created a multipurpose optimization problem for deciding the positions of watermarks in the frequency domain and obtaining a near-optimum solution. The near-optimum solution is obtained by using a genetic algorithm. The experimental results show that the proposed method generates watermarked audios of good quality and high tolerance to MP3 compression. In addition, the security was improved by using the characteristic secret key to embed and extract the watermark information. 展开更多
关键词 AUDIO WATERMARKING GENETIC Algorithm Optimization WAVELET Transforms SECRET Key
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