Automatic Segmentation of Liver and Vessels from CT Images for Liver Surgery Planning

( Xiaopeng Yang ),( Younggeun Choi ),( Jae Do Yang ),( Hong Pil Hwang ),( Sung Woo Ahn ),( Ji Hyun Kim ),( Hee Cheon You ),( Hee Chul Yu ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: To present a method for automatic segmentation of liver and its vessels from computer tomography (CT) images for liver surgery planning. Methods: The proposed method consists of three steps: Firstly, the liver is automatically segmented based on histogram analysis and its geometric characteristics by a method which incorporates a fast-marching level-set method and a threshold-based level-set method, in which optimal values of parameters are determined by an exhaustive experiment. Secondly, liver vessels including PV and HV are automatically segmented by a region growing method based on histogram analysis of the image region inside the liver. PV and HV are then separated by a connected component analysis method. Lastly, the liver is divided into 8 segments according to the Couinaud classification by a nearest neighbor approximation method. Results: Experiments were conducted using a public liver database consisting of 20 training and 10 test datasets from the SLIVER07 competition. Optimal parameter values for segmentation were determined by an exhaustive experiment using the 20 training datasets, while performance of the segmentation method was evaluated by using the 10 test datasets. The proposed liver segmentation method was ranked as the 6th best segmentation method out of 104 submissions (2016). For liver vessel segmentation, no false positive errors were found for all datasets. False negative errors were identified at distal vessel branches due to small diameter and low contrast. The average (± S.D.) score of suitability of the segmented liver vessels for liver surgery planning assessed by an expert radiologist was 6.4 (± 0.7) out of 7. Conclusions: The proposed method achieved high performance in liver segmentation by quantitative onsite evaluation and satisfactory performance in liver vessel segmentation assessed by an expert radiologist. The proposed method can be applied to liver surgery planning.

Development of a User-Centered Virtual Liver Surgery System

Xiaopeng Yang,Wonsup Lee,Younggeun Choi,Heecheon You,Ji Hyun Kim,Hee Chul Yu,Baik Hwan Cho 대한인간공학회 2011 대한인간공학회 학술대회논문집 Vol.2011 No.5

Objective: The present study is to develop a user-centered virtual surgery system called Dr. Liver which has clinical applicability and effectiveness to support liver surgery. Materials and methods: The major functions of Dr. Liver include (1) extraction of the liver, vessels, and tumors from abdominal CT images, (2) estimation of the standard liver volume of a patient, (3) volumetry of the extracted liver, vessels, and tumors, (4) segmentation of the liver based on the portal vein structure, and (5) support of surgery planning. A novel semi-automatic liver extraction algorithm was developed and implemented to Dr. Liver for time efficiency and accuracy of extraction. Dr. Liver was evaluated using MDCT data of three patients and compared to the OsriX system in terms of time and accuracy. Results: Dr. Liver was found significantly better than the OsriX system by showing an average (SD) time of liver extraction = 4.4 (2.4) min and an average difference between the volume of a manually extracted liver and that of the corresponding semi-automatically extracted liver = 4.2 (8.9) ml. Furthermore, various user-friendly features such as a procedural interface of virtual surgery planning were implemented into Dr. Liver for usability. Conclusions: It is concluded that Dr. Liver is a clinically effective tool to support liver surgery planning. More sophisticated features and functions are being developed and implemented to Dr. Liver to provide a surgeon with effective information for rational planning of liver surgery.

A User-Centered Virtual Liver Surgery Planning System

Xiaopeng Yang,Wonsup Lee,Younggeun Choi,Heecheon You,Ji Hyun Kim,Hee Chul Yu,Baik Hwan Cho 대한인간공학회 2012 대한인간공학회 학술대회논문집 Vol.2012 No.11

The present study is intended to develop a user-centered virtual liver surgery planning system called Dr. Liver which has clinical applicability and effectiveness to support liver surgery. Existing virtual surgery systems needs to be customized to liver surgery and improved for better usability and time efficiency. A use scenario of a virtual liver surgery planning system was established through literature review, benchmarking, and interviews with surgeons. Based on the use scenario, detailed liver surgery planning procedures were defined. The major functions of Dr. Liver include (1) extraction of the liver, vessels, and tumors from abdominal CT images, (2) estimation of the standard liver volume of a patient, (3) volumetry of the extracted liver, vessels, and tumors, (4) segmentation of the liver into 8 segments based on structures of the extracted portal and hepatic veins, and (5) support of surgery planning. Novel algorithms were developed and implemented into Dr. Liver for accuracy and time efficiency. Various user-friendly features such as a procedural interface of virtual liver surgery planning were integrated into Dr. Liver for better usability. Dr. Liver would be applied to safe and rational planning of liver surgery.

Development and Usability Testing of a User-Centered 3D Virtual Liver Surgery Planning System

Xiaopeng Yang,Hee Chul Yu,Younggeun Choi,Wonsup Lee,Jaedo Yang,Ji Hyun Kim,Baik Hwan Cho,Heecheon You 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.11

The present study developed a user-centered 3D virtual liver surgery planning system called Dr. Liver, which has clinical applicability and effectiveness to support liver surgery. Use scenarios of Dr. Liver were developed through literature review, benchmarking, and interviews with surgeons. User interfaces of Dr. Liver were designed with various user-friendly features such as hierarchical dropdown menus, hotkey menus provided on the screen, and 3D view indication box and resetting buttons. Novel image processing algorithms were developed and implemented into Dr. Liver for accurate and efficient liver surgery planning. Potential usability problems were identified by a preliminary usability testing at the early development stage and improvements were made for the identified usability problems. A usability testing showed that the improved Dr. Liver achieved higher time efficiency (= 21.8 ± 4.4 min) and overall user satisfaction (= 6.2 ± 0.7) than the previous version (time = 36.6 ± 1.7 min; overall satisfaction = 5.6 ± 0.5). The development and evaluation process of Dr. Liver in this study would help practitioners develop a user-friendly virtual surgery planning system.

An Analysis on Serious Games and Stakeholders’ Needs for Vocal Training Game Development

Xiaopeng Yang(양샤오펑),Edwina Dwi Sadika(에드위나 사디카),Gradiyan Budi Pratama(그라디안 프라타),Younggeun Choi(최영근),Yu-Kyung Kim(김유경),Ji-Yun Lee(이지윤),Yunju Jo(조윤주),Giwook Kim(김기욱),Jin-Kook Lee(이진국),Min-Jung Yu(유민정),M 한국언어청각임상학회 2019 Communication Sciences and Disorders Vol.24 No.3

배경 및 목적: 본 연구는 발성훈련에 대한 언어치료 환자의 치료 동기와 참여를 향상시키기 위한 기능성 게임에 대한 요구사항과 개발방향을 파악하기 위해 수행되었다. 방법: 문헌조사, 이해당사자 요구조사, 기존 3가지 발성훈련 게임(Visi Pitch, Dr. Speech, Vox System)의 벤치마킹 분석이 수행되었다. 결과: 문헌조사를 통해 13가지 게임 사용자 경험 척도들(유용성, 서사성, 몰입, 즐거움, 창의성, 오디오 심미성, 개인적 충족감, 사회적 연결성, 시각적 심미성, 정확성, 개인 맞춤형 분석, 게임 분석, 치료 연속성)이 파악되었다. 사용자 경험 척도들 중 기존 언어치료게임에서 일반적으로 미흡한 속성들로는 창의성(평균 만족도=2.5-4.3; Likert 7점 척도 사용), 사회적 연결성(2.4-4.4), 치료 연속성(1.7-4.7), 그리고 개인 맞춤형(2.5-5.0)이 파악되었다. 논의 및 결론: 본 연구의 사용자 경험 척도들은 발성훈련 기능성 게임을 평가하는 데 유용하게 활용될 수 있으며, 기존의 게임들이 상대적으로 미흡한 사용성 경험 척도를 보완하는 새로운 기능성 게임 개발이 필요하다. Objectives: The present study intended to identify the needs and development directions of a serious vocal training game for better motivation and commitment of patients with voice disorder to voice therapy. Methods: A literature review, a survey of stakeholders’ needs, and a benchmarking analysis of three vocal training games (Visi Pitch, Dr. Speech, and Vox System) was conducted. Results: From the literature review, thirteen game user experience scales (usability, narratives, play engrossment, enjoyment, creative freedom, audio aesthetics, personal gratification, social connectivity, visual aesthetics, accuracy, customization, game analytics, and therapy continuity) were identified for vocal training games and then applied to evaluation of the existing games. From the user experience scales, features not commonly implemented in the existing games include creative freedom (average satisfaction score, 2.5 to 4.3 out of 7), social connectivity (2.4 to 4.4), therapy continuity (1.7 to 4.7), and customization (2.5 to 5.0). Conclusion: The user experience scales would be of use to assess vocal training games, and new serious games need to be developed to complement the existing games in terms of the four scales found relatively lacking.

A Usability Test for Dr. Liver, a 3D Virtual Liver Surgical Planning System

Xiaopeng Yang,Younggeun Choi,Wonsup Lee,Baojian Wang,Jaedo Yang,Hongpil Hwang,Ji Hyun Kim,Jisoo Song,Hee Chul Yu,Baik Hwan Cho,Heecheon You 대한인간공학회 2013 대한인간공학회 학술대회논문집 Vol.2013 No.5

A usability test was performed for a 3D virtual liver surgical planning system, named Dr. Liver. The system consists of five modules including (1) (1) Liver Extraction, (2) Vessel Extraction, (3) Tumor Extraction, (4) Liver Segmentation, and (5) Liver Surgery Planning. Various performance and preference measures were applied and opinions of the participants regarding likes, dislikes, and suggestions were collected. Three medical doctors participated in the usability test, consisting of five test modules. The system received a high score of satisfaction (mean = 6.5, S.D. = 0.8) as measured using a 7-point Likert scale throughout the five test modules. Based on the evaluation results, recommendations were made for better usability of the system. The present study would help practitioners to evaluate the usability of a system and identify potential usability problems in a systematic manner.

Effect of machining parameters on surface integrity of silicon carbide ceramic using end electric discharge milling and mechanical grinding hybrid machining

Renjie Ji,Yonghong Liu,Yanzhen Zhang,Baoping Cai,Xiaopeng Li,Chao Zheng 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.1

A novel hybrid process that integrates end electric discharge (ED) milling and mechanical grinding is proposed. The process is able to effectively machine a large surface area on SiC ceramic with good surface quality and fine working environmental practice. The polarity, pulse on-time, and peak current are varied to explore their effects on the surface integrity, such as surface morphology, surface roughness, micro-cracks, and composition on the machined surface. The results show that positive tool polarity, short pulse on-time, and low peak current cause a fine surface finish. During the hybrid machining of SiC ceramic, the material is mainly removed by end ED milling at rough machining mode, whereas it is mainly removed by mechanical grinding at finish machining mode. Moreover, the material from the tool can transfer to the workpiece, and a combination reaction takes place during machining.

Honeypot game‐theoretical model for defending against APT attacks with limited resources in cyber‐physical systems

Wen Tian,Xiaopeng Ji,Weiwei Liu,Jiangztao Zhai,Guangjie Liu,Yauwei Dai,Shuhua Huang 한국전자통신연구원 2019 ETRI Journal Vol.41 No.5

A cyber‐physical system (CPS) is a new mechanism controlled or monitored by computer algorithms that intertwine physical and software components. Advanced persistent threats (APTs) represent stealthy, powerful, and well‐funded attacks against CPSs; they integrate physical processes and have recently become an active research area. Existing offensive and defensive processes for APTs in CPSs are usually modeled by incomplete information game theory. However, honeypots, which are effective security vulnerability defense mechanisms, have not been widely adopted or modeled for defense against APT attacks in CPSs. In this study, a honeypot game‐theoretical model considering both low‐ and high‐interaction modes is used to investigate the offensive and defensive interactions, so that defensive strategies against APTs can be optimized. In this model, human analysis and honeypot allocation costs are introduced as limited resources. We prove the existence of Bayesian Nash equilibrium strategies and obtain the optimal defensive strategy under limited resources. Finally, numerical simulations demonstrate that the proposed method is effective in obtaining the optimal defensive effect.

Designing Rich-Secure Network Covert Timing Channels Based on Nested Lattices

( Weiwei Liu ),( Guangjie Liu ),( Xiaopeng Ji ),( Jiangtao Zhai ),( Yuewei Dai ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.4

As the youngest branch of information hiding, network covert timing channels conceal the existence of secret messages by manipulating the timing information of the overt traffic. The popular model-based framework for constructing covert timing channels always utilizes cumulative distribution function (CDF) of the inter-packet delays (IPDs) to modulate secret messages, whereas discards high-order statistics of the IPDs completely. The consequence is the vulnerability to high-order statistical tests, e.g., entropy test. In this study, a rich security model of covert timing channels is established based on IPD chains, which can be used to measure the distortion of multi-order timing statistics of a covert timing channel. To achieve rich security, we propose two types of covert timing channels based on nested lattices. The CDF of the IPDs is used to construct dot-lattice and interval-lattice for quantization, which can ensure the cell density of the lattice consistent with the joint distribution of the IPDs. Furthermore, compensative quantization and guard band strategy are employed to eliminate the regularity and enhance the robustness, respectively. Experimental results on real traffic show that the proposed schemes are rich-secure, and robust to channel interference, whereas some state-of-the-art covert timing channels cannot evade detection under the rich security model.

Estimation of Standard Liver Volume Using Computed Tomographic Volumetry Data, Body Composition Data, and Abdomen Fat Measurement Data

( Jae Do Yang ),( Xiaopeng Yang ),( Seunghoon Lee ),( Hong Pil Hwang ),( Sung Woo Ahn ),( Ji Hyun Kim ),( Hee Cheon You ),( Hee Chul Yu ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Regression equations for estimation of standard liver volume (SLV, mL) using conventional variables including age, gender, body weight (BW, kg), body height (BH, cm), body surface area (BSA, m˛), and body mass index (BMI) have been developed. However, for more accurate estimation of SLV, use of balanced data by gender and additional regressors such as body composition data and abdomen fat measurement data which may affect SLV need to be considered. Methods: The present study used 910 cases of abdominal CT images from healthy adults collected from Chonbuk National University Hospital. The present study developed SLV estimation regression formulas for two groups of data: (1) gender-balanced and (2) gender- unbalanced. From each data group, three formulas using (1) conventional variables (2) conventional and body composition variables including skeletal body mass (SMM, kg), fat mass (FM, kg), body fat percentage (BFP), and abdominal fat percentage (AFP), and (3) conventional, body composition, and abdomen fat variables including waist circumference (WC, cm), subcutaneous fat area (SFA, cm˛), and visceral fat area (VFA, cm2) were developed. The liver volume of abdominal CT images was measured using Dr. Liver. Results: The gender-balanced formulas showed better performance than the gender-unbalanced formulas and inclusion of body composition and abdomen fat measurements contributed to enhancing performance of SLV estimation regression. The best regression model is SLV = -582 + 16.0 BW - 4.19 age - 102.0 gender - 8.13 BFP + 1468 AFP - 0.00826 SFA(adj. R2 = 0.56, %AE = 12.2% ± 10.0%, percentage of %AE > 20% = 21.2% ) in the present study. Conclusions: The regression equations developed in this study can be used in estimation of SLV with higher accuracy in liver surgery planning.