Tamper Localization and Lossless Recovery Watermarking Scheme with ROI Segmentation and Multilevel Authentication

Tamper localization and recovery watermarking scheme can be used to detect manipulation and recover tampered images. In this paper, a tamper localization and lossless recovery scheme that used region of interest (ROI) segmentation and multilevel authentication was proposed. The watermarked images had a high average peak signal-to-noise ratio of 48.7 dB and the results showed that tampering was successfully localized and tampered area was exactly recovered. The usage of ROI segmentation and multilevel authentication had significantly reduced the time taken by approximately 50 % for the tamper localization and recovery processing.     

An Improved Tamper Detection and Localization Scheme for Volumetric DICOM Images

The development of teleradiology brings the convenience of global medical record access along with the concerns over the security of medical images transmitted over the open network. With the prevailing adoption of three-dimensional (3-D) imaging modalities, it is vital to develop a security mechanism to provide large volumes of medical images with privacy and reliability. This paper presents the development of a new and improved method of implementing tamper detection and localization based on a fully reversible digital watermarking scheme for the protection of volumetric DICOM images. This tamper detection and localization method utilizes the 3-D property of volumetric data to achieve much faster processing time at both sender and receiver sides without compromising tamper localization accuracy. The performance of the proposed scheme was evaluated by using sample volumetric DICOM images. Results show that the scheme achieved on average about 65 % and 72 % reduction in watermarking and dewatermarking processing time, respectively. For cases where the images had been tampered, it is possible to detect and localize the tampered areas with improved localization resolution in the images using the scheme.     

Fusion Viewer: A New Tool for Fusion and Visualization of Multimodal Medical Data Sets

Digital medical images are very easy to be modified for illegal purposes. For example, microcalcification in mammography is an important diagnostic clue, and it can be wiped off intentionally for insurance purposes or added intentionally into a normal mammography. In this paper, we proposed two methods to tamper detection and recovery for a medical image. A 1024 × 1024 x-ray mammogram was chosen to test the ability of tamper detection and recovery. At first, a medical image is divided into several blocks. For each block, an adaptive robust digital watermarking method combined with the modulo operation is used to hide both the authentication message and the recovery information. In the first method, each block is embedded with the authentication message and the recovery information of other blocks. Because the recovered block is too small and excessively compressed, the concept of region of interest (ROI) is introduced into the second method. If there are no tampered blocks, the original image can be obtained with only the stego image. When the ROI, such as microcalcification in mammography, is tampered with, an approximate image will be obtained from other blocks. From the experimental results, the proposed near-lossless method is proven to effectively detect a tampered medical image and recover the original ROI image. In this study, an adaptive robust digital watermarking method combined with the operation of modulo 256 was chosen to achieve information hiding and image authentication. With the proposal method, any random changes on the stego image will be detected in high probability.     

PACS系统影像存储解决方案

医学图像存档与传输系统(PACS)是目前数字化医院建设的重点和难点,PACS系统需要一个高性能的影像存储系统支撑.本文分析了PACS系统影像存储的特点,介绍了分级存储机制实现对医学影像的存储管理,并比较了三种在线存储设备解决方案的优点和缺点.     

A Heuristic Automatic and Robust ROI Detection Method for Medical Image Warermarking

This paper presents an automatic region of interest (ROI) segmentation method for application of watermarking in medical images. The advantage of using this scheme is that the proposed method is robust against different attacks such as median, Wiener, Gaussian, and sharpening filters. In other words, this technique can produce the same result for the ROI before and after these attacks. The proposed algorithm consists of three main parts; suggesting an automatic ROI detection system, evaluating the robustness of the proposed system against numerous attacks, and finally recommending an enhancement part to increase the strength of the composed system against different attacks. Results obtained from the proposed method demonstrated the promising performance of the method.     

Migration of Medical Image Data Archived Using Mini-PACS to Full-PACS

This study evaluated the migration to full-PACS of medical image data archived using mini-PACS at two hospitals of the Yonsei University Medical Center, Seoul, Korea. A major concern in the migration of medical data is to match the image data from the mini-PACS with the hospital OCS (Ordered Communication System). Prior to carrying out the actual migration process, the principles, methods, and anticipated results for the migration with respect to both cost and effectiveness were evaluated. Migration gateway workstations were established and a migration software tool was developed. The actual migration process was performed based on the results of several migration simulations. Our conclusions were that a migration plan should be carefully prepared and tailored to the individual hospital environment because the server system, archive media, network, OCS, and policy for data management may be unique.     

Multidimensional Analysis: A Management Tool for Monitoring HIPAA Compliance and Departmental Performance

Most RIS and PACS systems include extensive auditing capabilities as part of their security model, but inspecting those audit logs to obtain useful information can be a daunting task. Manual analysis of audit trails, though cumbersome, is often resorted to because of the difficulty to construct queries to extract complex information from the audit logs. The approach proposed by the authors uses standard off-the-shelf multidimensional analysis software tools to assist the PACS/RIS administrator and/or security officer in analyzing those audit logs to identify and scrutinize suspicious events. Large amounts of data can be quickly reviewed and graphical analysis tools help explore system utilization. While additional efforts are required to fully satisfy the demands of the ever-increasing security and confidentiality pressures, multidimensional analysis tools are a practical step toward actually using the information that is already being captured in the systems audit logs. In addition, once the work is performed to capture and manipulate the audit logs into a viable format for the multidimensional analysis tool, it is relatively easy to extend the system to incorporate other pertinent data, thereby enabling the ongoing analysis of other aspects of the departments workflow.     

A Review of Medical Image Watermarking Requirements for Teleradiology

Teleradiology allows medical images to be transmitted over electronic networks for clinical interpretation and for improved healthcare access, delivery, and standards. Although such remote transmission of the images is raising various new and complex legal and ethical issues, including image retention and fraud, privacy, malpractice liability, etc., considerations of the security measures used in teleradiology remain unchanged. Addressing this problem naturally warrants investigations on the security measures for their relative functional limitations and for the scope of considering them further. In this paper, starting with various security and privacy standards, the security requirements of medical images as well as expected threats in teleradiology are reviewed. This will make it possible to determine the limitations of the conventional measures used against the expected threats. Furthermore, we thoroughly study the utilization of digital watermarking for teleradiology. Following the key attributes and roles of various watermarking parameters, justification for watermarking over conventional security measures is made in terms of their various objectives, properties, and requirements. We also outline the main objectives of medical image watermarking for teleradiology and provide recommendations on suitable watermarking techniques and their characterization. Finally, concluding remarks and directions for future research are presented.     

Pseudonymization of Radiology Data for Research Purposes

Medical image processing methods and algorithms, developed by researchers, need to be validated and tested. Test data would ideally be real clinical data especially that clinical data is varied and exists in large volumes. Nowadays, clinical data is accessible electronically and has important value for researchers. However, the usage of clinical data for research purposes should respect data confidentiality, patient right to privacy, and patient consent. In fact, clinical data is nominative given that it contains information about the patient such as name, age, and identification number. Evidently, clinical data needs to be de-identified to be exported to research databases. However, the same patient is usually followed during a long period of time. The disease progression and the diagnostic evolution represent extremely valuable information for researchers as well. Our objective is to build a research database from de-identified clinical data while enabling the data set to be easily incremented by exporting new pseudonymous data, acquired over a long period of time. Pseudonymization is data de-identification, such that data belonging to an individual in the clinical environment still belong to the same individual in the de-identified research version. In this paper, we explore various software architectures to enable the implementation of an imaging research database that can be incremented in time. We also evaluate their security and discuss their security pitfalls. As most imaging data accessible electronically is available with the digital imaging and communication in medicine (DICOM) standard, we propose a de-identification scheme that closely follows DICOM recommendations. Our work can be used to enable electronic health record (EHR) secondary usage such as public surveillance and research, while maintaining patient confidentiality.     

关于基于可扩展PACS的医学影像处理科研教学实验室建设的设想

目的：提出了在高校医学影像工程专业建设一个先进的医学影像处理科研教学实验室的设想,以促进医、工、教、研的结合,并方便医学图像处理科研、教学乃至产业化。方法：首先建立基于可扩展PACS系统的研究平台,并在此基础上构建可扩展影像数据库和相关软硬件技术研发平台．逐步形成实验室科研教学所需要的硬环境,同时建立必要的管理制度、项目培育和激励机制以及研究生和优秀本科生能力培养机制等软环境．然后随着实验室与医院和产业界合作程度的加深以及学生毕业后走向社会的“滚动式”的反馈和影响,使得实验室的运作逐步形成良性循环和长效机制。结果：建立这样的实验室不但会方便科研、教学,还可紧扣医院的临床需求把医学影像产品的研发与产业化密切联系在一起,能够形成一个医、工、教、研交叉融合的良好平台和媒介。结论：充分体现卓越工程师教育的新思想和理念,通过不断增强实验室基础职能及其平台和媒介作用,可逐步形成一种范式。可以预见该类实验室建设和良性运作必将同时受到实验室师生、医院相关医生和产业界涉众的欢迎和支持。其对产学研密切结合的教研模式的研究不失为一种有益的试验和探索。     

Bio-Image Warehouse System: Concept and Implementation of a Diagnosis-Based Data Warehouse for Advanced Imaging Modalities in Neuroradiology

Advanced neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), chemical shift spectroscopy imaging (CSI), diffusion tensor imaging (DTI), and perfusion-weighted imaging (PWI) create novel challenges in terms of data storage and management: huge amounts of raw data are generated, the results of analysis may depend on the software and settings that have been used, and most often intermediate files are inherently not compliant with the current DICOM (digital imaging and communication in medicine) standard, as they contain multidimensional complex and tensor arrays and various other types of data structures. A software architecture, referred to as Bio-Image Warehouse System (BIWS), which can be used alongside a radiology information system/picture archiving and communication system (RIS/PACS) system to store neuroimaging data for research purposes, is presented. The system architecture is conceived with the purpose of enabling to query by diagnosis according to a predefined two-layered classification taxonomy. The operational impact of the system and the time needed to get acquainted with the web-based interface and with the taxonomy are found to be limited. The development of modules enabling automated creation of statistical templates is proposed.     

医院备份系统解决方案

我们介绍了一个医院数据备份系统方案。分析了备份系统方案的设计目标 :对医院业务系统和数据库建立一个集中管理的、自动化的、高速有效的备份手段     

Assessment of a Novel,High-Resolution,Color, AMLCD for Diagnostic Medical Image Display: Luminance Performance and DICOM Calibration

This article documents the results of the first in a series of experiments designed to evaluate the suitability of a novel, high resolution, color, digital, liquid crystal display (LCD) panel for diagnostic quality, gray scale image display. The goal of this experiment was to measure the performance of the display, especially with respect to luminance. The panel evaluated was the IBM T221 22.2 backlit active matrix liquid crystal display (AMLCD) with native resolution of 3840 × 2400 pixels. Taking advantage of the color capabilities of the workstation, we were able to create a 256-entry grayscale calibration look-up table derived from a palette of 1786 nearly gray luminance values. We also constructed a 256-entry grayscale calibration look-up table derived from a palette of 256 true gray values for which the red, green, and blue values were equal. These calibrations will now be used in our evaluation of human contrast-detail perception on this LCD panel.     

A New Family of Distance Functions for Perceptual Similarity Retrieval of Medical Images

A long-standing challenge of content-based image retrieval (CBIR) systems is the definition of a suitable distance function to measure the similarity between images in an application context which complies with the human perception of similarity. In this paper, we present a new family of distance functions, called attribute concurrence influence distances (AID), which serve to retrieve images by similarity. These distances address an important aspect of the psychophysical notion of similarity in comparisons of images: the effect of concurrent variations in the values of different image attributes. The AID functions allow for comparisons of feature vectors by choosing one of two parameterized expressions: one targeting weak attribute concurrence influence and the other for strong concurrence influence. This paper presents the mathematical definition and implementation of the AID family for a two-dimensional feature space and its extension to any dimension. The composition of the AID family with L _p distance family is considered to propose a procedure to determine the best distance for a specific application. Experimental results involving several sets of medical images demonstrate that, taking as reference the perception of the specialist in the field (radiologist), the AID functions perform better than the general distance functions commonly used in CBIR.     

磁共振图像k空间数据分析与处理PC平台的开发与应用

目的：开发基于普通PC的软件包,实现磁共振图像k空间数据的读取分析与多种后处理。方法：根据磁共振原始数据的存储规则和文件结构,开发读取磁共振图象k空间数据的PC平台,读取文件头相关信息（图像层数,回波采样点数,相位编码步数,数据偏移量等关系后续图像重建、分析、处理的重点参数必须读出备用,其它辅助参数可不读出,若将来用到,可添加读出代码即可）,开辟内存空间,线性k空间数据读出到内存,根据前面参数提供的信息进行各层面数据重组。各种序列参数放在hd结构中,数据放在data矩阵中。对数据矩阵进行各种处理。结果：在该平台上,可成功进行磁共振原始k空间数据的读取、显示、分析和重建处理及各种后处理操作（图象重建;幅度、实部、虚部、相位的分别显示;锐化、模糊等各种处理）。结论：软件包成功实现了各项预先设计功能,利用该方法开发磁共振图像k空间数据分析与处理PC平台切实可行。     

基于医学图像的人体组织有限元模型的建立方法

在医学图像处理、分析和一些成像算法重构中,建立准确的人体组织轮廓外形和有限元模型对于图像分析和改善重构算法的性能、提高分析和重构结果的准确性具有重要作用。本文使用图像处理与曲线拟合的办法,提取CT图像中的真实人体边界,进行分层的有限元剖分与相关参数设置,获得基于真实人体的有限元重构模型。该方法构建的有限元重构模型已在医学图像处理实际工作中得到了初步的应用。     

Imaging Facilities for Basic Medical Units: A Case in the State of Guerrero, Mexico

This work presents the methodology to design a small imaging unit in a small regional hospital that takes into account the real imaging needs in the region regardless of current administrative guidelines. The situation of the imaging facilities in Mexico’s states is studied and compared with other countries, and a project plan is designed for the specific state (Guerrero) where the clinic is to be located. The proposal includes the acquisition of a basic suite of modalities that include an ultrasound system, a mammography unit, and a conventional X-ray system in addition to a CT system that is not available anywhere within the state. The system should be primarily digital and should incorporate a simple picture archiving and communications system that can be the basis of a future telemedicine unit. The conclusion of this study also proposes changes in the segmented and pyramidal structure of the Mexican health system in order to provide higher quality care at the lower level, to reduce bottlenecks, and to provide higher quality health care near the patient’s home.     

Use of a Thin-Section Archive and Enterprise 3-Dimensional Software for Long-Term Storage of Thin-Slice CT Data Sets—A Reviewers’ Response

Current developments in storage solutions, PACS, and client-server systems allow for 3D imaging at the desktop. This can be achieved together with full storage into PACS of all slices, including the very large thin-section CT datasets. This paper describes a possible setup, which has been in operation for several years now, in response to an article by Meenan et al. previously published in this journal (1).