Kyoung Ho Lee

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This study aimed to evaluate three image fidelity metrics of different computational principles--peak signal-to-noise ratio (PSNR), high-dynamic range visual difference predictor (HDR-VDP), and multiscale structural similarity (MS-SSIM)--in measuring the fidelity of JPEG2000 compressed abdomen computed tomography images from a viewpoint of visually lossless(More)
BACKGROUND Fat accumulation in android compartments may confer increased metabolic risk. The incremental utility of measuring regional fat deposition in association with metabolic syndrome (MS) has not been well described particularly in an elderly population. METHODS AND FINDINGS As part of the Korean Longitudinal Study on Health and Aging, which is a(More)
This paper presents an efficient feature-based nonrigid registration method for multiphase liver CT volumes. While radiologists routinely examine mul-tiphase liver CT to detect hepatic diseases, they usually search corresponding points between 3D CT volumes by visual inspections using 2D slice images. As the liver is a deformable organ, there exist complex(More)
OBJECTIVE To show the advantages of extended field-of-view sonography in abdominal applications. METHODS Thirty-one cases were prospectively analyzed in our study. Extended field-of-view images were obtained when the radiologist decided that they would offer potential advantages for the examination. When extended field-of-view scanning was used, the(More)
PURPOSE To compare computed tomographic (CT) image interpretation with picture archiving and communication systems (PACS) stack and tile modes for speed and accuracy of transition zone localization in small-bowel obstruction by using ex vivo porcine specimens. MATERIALS AND METHODS Twenty-five small-bowel obstruction phantom models made of ex vivo porcine(More)
Inspired by the ModelFest and ColorFest data sets, a contrast sensitivity function was measured for a wide range of adapting luminance levels. The measurements were motivated by the need to collect visual performance data for natural viewing of static images at a broad range of luminance levels, such as can be found in the case of high dynamic range(More)
OBJECTIVE To compare the in-vitro efficiency of a hypertonic saline (HS)-enhanced bipolar radiofrequency (RF) system with monopolar RF applications by assessing the temperature profile and dimensions of RF-created coagulation necrosis in bovine liver. MATERIALS AND METHODS A total of 27 ablations were performed in explanted bovine livers. After placement(More)
We propose a system that automatically generates multiplanar reformation (MPR) images on-the-fly, which is independent of computed tomography (CT) scanner type. Triggered by digital imaging communication in medicine (DICOM) Storage Commitment or in a time threshold manner, this system generates MPR images from received thin-section CT data sets with(More)
Many visual difference predictors (VDPs) have used basic psychophysical data (such as ModelFest) to calibrate the algorithm parameters and to validate their performances. However, the basic psychophysical data often do not contain sufficient number of stimuli and its variations to test more complex components of a VDP. In this paper we calibrate the Visual(More)
With the increased temporal resolution available in dynamic computed tomography (CT) and magnetic resonance imaging (MRI), hepatic arterioportal shunts are now more frequently encountered than in the past. The condition occurs in various hepatic diseases in which portal or hepatic venous flow is compromised. The underlying mechanism and the degree of shunt(More)