ICT in telemedicine: conquering privacy and security issues in health care services

Advancement in telecommunication combined with improved information technology infrastructures has opened up new dimensions in e-health environment. Such technologies make readily available to access, store, manipulate and replicate medical information and images. These technologies help reduced the time and effort in diagnoses and treatment at lower cost. However, protection and authentication of such medical information and images are now becoming increasingly important in telemedicine environment, where images are readily distributed over electronic networks. Intruders/hackers may gain access to confidential information and possible alter or even delete such vital records. The ultimate success of telemedicine demands an effective technology as well as privacy and security of records should be main concern. This paper explores recent identified privacy and security issues that affect telemedicine. Featuring threats on security and authentication of medical records, and proposing digital watermarking as a technology to curb authentication issues in telemedicine is highlighted

Assessment of perceptual distortion boundary through applying reversible watermarking to brain MR images

The digital medical workflow faces many circumstances in which the images can be manipulated during viewing, extracting and exchanging. Reversible and imperceptible watermarking approaches have the potential to enhance trust within the medical imaging pipeline through ensuring the authenticity and integrity of the images to confirm that the changes can be detected and tracked. This study concentrates on the imperceptibility issue. Unlike reversibility, for which an objective assessment can be easily made, imperceptibility is a factor of human cognition that needs to be evaluated within the human context. By defining a perceptual boundary of detecting the modification, this study enables the formation of objective guidelines for the method of data encoding and level of image/pixel modification that translates to a specific watermark magnitude. This study implements a relative Visual Grading Analysis (VGA) evaluation of 117 brain MR images (8 original and 109 watermarked), modified by varying techniques and magnitude of image/pixel modification to determine where this perceptual boundary exists and relate the point at which change becomes noticeable to the objective measures of the image fidelity evaluation. The outcomes of the visual assessment were linked to the images Peak Signal to Noise Ratio (PSNR) values, thereby identifying the visual degradation threshold. The results suggest that, for watermarking applications, if a watermark is applied to the 512x512 pixel (16 bpp grayscale) images used in the study, a subsequent assessment of PSNR=82dB or greater would mean that there would be no reason to suspect that the watermark would be visually detectable. Keywords: Medical imaging; DICOM; Reversible Watermarking; Imperceptibility; Image Quality; Visual Grading Analysis

Medical image encryption techniques: a technical survey and potential challenges

Among the most sensitive and important data in telemedicine systems are medical images. It is necessary to use a robust encryption method that is resistant to cryptographic assaults while transferring medical images over the internet. Confidentiality is the most crucial of the three security goals for protecting information systems, along with availability, integrity, and compliance. Encryption and watermarking of medical images address problems with confidentiality and integrity in telemedicine applications. The need to prioritize security issues in telemedicine applications makes the choice of a trustworthy and efficient strategy or framework all the more crucial. The paper examines various security issues and cutting-edge methods to secure medical images for use with telemedicine systems

Distortion-Free Digital Watermarking for Medical Images (Fundus) using Complex- Valued Neural Network

Fundus image is the interior surface of the eye that includes the optic nerves, macula and retinal blood vessels. The optic nerve which is responsible for transmitting of electrical impulses from the retina to the brain is connected to the back of the eye near the macula has a visible portion of the optic nerve called the optic disc. Optic disk has been shown to provide diagnostic information related to diabetic retinopathy (DR) and glaucoma diseases. Since such image are used for early detection of numbers of ocular disease which still remain the legal cause of blindness in working age population. Protection and authentication of such medical images are now becoming increasingly important in an e-Health environment. Though several high-ranking watermarking schemes using neural networks have been proposed in order to make watermark stronger in protection of medical images to resist attacks. However, the current system only deals with real value data. Once the data become complex, the current algorithms are not capable of handling complex data. In this study, a distortion-free digital watermarking scheme based on Complex-Valued Neural Network (CVNN) in transform domain is proposed. Fast Fourier Transform (FFT) was used to obtain the complex number (real and imaginary part) of the host image. The complex values form the input data of the Complex Back-Propagation (CBP) algorithm. Because neural networks perform best on detection, classification, learning and adaption, these features are employed to simulate the Safe Region (SR) to embed the watermark, thus, watermark are appropriately mapped to the mid frequency of selected coefficients. The algorithm was appraised by Mean Squared Error MSE and Average Difference Indicator (ADI). Implementation results have shown that this watermarking algorithm has a high level of robustness and accuracy in recovery of the watermark

Reversible and imperceptible watermarking approach for ensuring the integrity and authenticity of brain MR images

The digital medical workflow has many circumstances in which the image data can be manipulated both within the secured Hospital Information Systems (HIS) and outside, as images are viewed, extracted and exchanged. This potentially grows ethical and legal concerns regarding modifying images details that are crucial in medical examinations. Digital watermarking is recognised as a robust technique for enhancing trust within medical imaging by detecting alterations applied to medical images. Despite its efficiency, digital watermarking has not been widely used in medical imaging. Existing watermarking approaches often suffer from validation of their appropriateness to medical domains. Particularly, several research gaps have been identified: (i) essential requirements for the watermarking of medical images are not well defined; (ii) no standard approach can be found in the literature to evaluate the imperceptibility of watermarked images; and (iii) no study has been conducted before to test digital watermarking in a medical imaging workflow. This research aims to investigate digital watermarking to designing, analysing and applying it to medical images to confirm manipulations can be detected and tracked. In addressing these gaps, a number of original contributions have been presented. A new reversible and imperceptible watermarking approach is presented to detect manipulations of brain Magnetic Resonance (MR) images based on Difference Expansion (DE) technique. Experimental results show that the proposed method, whilst fully reversible, can also realise a watermarked image with low degradation for reasonable and controllable embedding capacity. This is fulfilled by encoding the data into smooth regions (blocks that have least differences between their pixels values) inside the Region of Interest (ROI) part of medical images and also through the elimination of the large location map (location of pixels used for encoding the data) required at extraction to retrieve the encoded data. This compares favourably to outcomes reported under current state-of-art techniques in terms of visual image quality of watermarked images. This was also evaluated through conducting a novel visual assessment based on relative Visual Grading Analysis (relative VGA) to define a perceptual threshold in which modifications become noticeable to radiographers. The proposed approach is then integrated into medical systems to verify its validity and applicability in a real application scenario of medical imaging where medical images are generated, exchanged and archived. This enhanced security measure, therefore, enables the detection of image manipulations, by an imperceptible and reversible watermarking approach, that may establish increased trust in the digital medical imaging workflow

Assuring authenticity of digital mammograms by image watermarking

Wide availability of medical images in digital form introduces risk of changes to the image data, whether by deliberate or accidental means. Some level of protection is afforded by use of encapsulating software such as PACS and other image storage systems, and by making use of file format information (e.g. DICOM header fields). However a greater degree of assurance can be obtained by embedding a subtle hidden pattern within the actual image data, an approach termed image watermarking. The effect of adding the watermark must be below the perceptual threshold of a skilled observer, and must not measurably affect the performance of readers. This paper uses an approach developed specifically for medical image watermarking, and describes efforts to validate its effects on digital mammograms according to the above criteria. The operating region based on embedding strength values for two watermarking methods (DCT and DWT) in the vicinity of the perceptual threshold was characterized using two established perceptual quality metrics (PSNR and SVDP Sum). Subjective testing was then undertaken to compare these metric values with actual observer perception in a 2AFC experiment, and a clear perceptual threshold effect was found