Medical image on the go!

Exploring correlation information for image compression of four-dimensional computed tomography

Background

Nowadays four-dimensional computed tomography (4DCT) is popularly used in evaluating respiration-related organ motion for patients under radiotherapy. As consisting of multiple subsets of CT images, a larger storage space is needed for 4DCT. In this study, the correlations information within these subsets was explored and the popular video encoders were used for 4DCT image compression.

Methods

The images of 4DCT subsets were arranged in an order and put into a sequence for the input of video encoder. The effects of two ordering methods on the compression performance of video encoder were compared. One ordering method, phase-prioritized (PP) sequence, arranged 4DCT images according to their respiration phases. Another ordering method, location-prioritized (LP) sequence, arranged 4DCT images by their slice locations. Three popular video encoders were selected including one lossless compression algorithm and two lossy compression algorithms. Based on a publicly available database consisting of 82 4DCT datasets of 20 lung cancer patients, the performance of two ordering methods and three video encoders was quantitatively assessed.

Results

The highest compression ratios were 310 and 260 for LP and PP ordering methods respectively and achieved by one video encoder employing inter-frame prediction coding algorithm. The highest compression ratios for the other two video encoders employing intra-frame coding algorithms were 16 and 7. The LP ordering method showed less inter-frame variation and higher inter-frame similarity over the PP ordering method.

Conclusions

The LP ordering method would result in higher compression ratio than the PP ordering method for 4DCT image compression. The compression performance of video encoder employing inter-frame prediction coding algorithm is superior to those of video encoders employing intra-frame coding algorithms. The video encoder with inter-frame prediction coding algorithm and LP ordering method would be highly suitable for 4DCT image compression.

Evaluation of video compression methods for cone-beam computerized tomography

PURPOSE

Cone-beam computerized tomography (CBCT) is routinely performed for verification of patient position in radiotherapy. It produced a large amount of data which require a method to compress them for efficient storage. In this study three video compression algorithms were introduced and their performance was evaluated based on real patient data.

MATERIALS AND METHODS

At first CBCT images in multiple sets of a patient were transferred from reconstruction workstation or exported from treatment planning system. Then CBCT images were sorted according to imaging time (time-prioritized sequence) or imaging location (location-prioritized sequence). Next, this sequence was processed by a video compression algorithm and resulted in a movie. Three representative video compression algorithms (Motion JPEG 2000, Motion JPEG AVI, and MPEG-4) were employed and their compression performance was evaluated based on the CBCT data of 30 patients.

RESULTS

Among three video compression algorithms, Motion JPEG 2000 has the least compression ratio since it is a lossless compression algorithm. Motion JPEG AVI and MPEG-4 have higher compression ratios than Motion JPEG 2000 but come with certain image losses. For MPEG-4, location-prioritized sequences show higher compression ratio than time-prioritized sequences. Based on the results achieved on the clinical target verification application, the registration accuracy of CBCT after decompression was comparable to that of the original CBCT.

CONCLUSIONS

Video compression algorithms could provide a higher compression ratio comparing to static image compression algorithm. Although the loss of CBCT image due to compression its impact on registration accuracy of patient positioning is almost negligible. Video compression method is an effective way to substantially reduce the size of CBCT images for storage.

Mobile Volume Rendering: Past, Present and Future

Volume rendering has been a relevant topic in scientific visualization for the last decades. However, the exploration of reasonably big volume datasets requires considerable computing power, which has limited this field to the desktop scenario. But the recent advances in mobile graphics hardware have motivated the research community to overcome these restrictions and to bring volume graphics to these ubiquitous handheld platforms. This survey presents the past and present work on mobile volume rendering, and is meant to serve as an overview and introduction to the field. It proposes a classification of the current efforts and covers aspects such as advantages and issues of the mobile platforms, rendering strategies, performance and user interfaces. The paper ends by highlighting promising research directions to motivate the development of new and interesting mobile volume solutions.

Future trends in Picture Archiving and Communication System (PACS)

This research investigates the opinions of radiologists regards requirements for improving current Picture Archiving and Communication System (PACS). Responses to a questionnaire were collected from 120 of the 200 radiologists in five governmental hospitals of Kuwait. The study the determines the importance of the solutions for future PACS from the radiologists point of view as: PACS must be integrated with other hospital information systems (100%); there must be multi hospital PACS access across different organizations (99%); web based PACS solutions (97%) and PACS applications in mobile phones (97%) are seen as an improved solution for future PACS. Whereas, the radiologists expressed strong concerns over the barriers for implementing web PACS solutions including: technical issues (91%); lack of training (85%); and cost (76%).

Mobile Health (mHealth) biomedical imaging paradigm

Technology assisted methods for medical diagnosis and biomedical health monitoring are rapidly shifting from classical invasive methods to handheld-based non-invasive approaches. Biomedical imagining is one of the most prominent practices of non-invasive mechanisms in medical applications. This paper considers the medical imaging schemes for Mobile Health (mHealth) applications and studies the feasibility of future mobile systems for accommodating image informatics capabilities.

A web service system supporting three-dimensional post-processing of medical images based on WADO protocol

Three-dimensional post-processing operations on the volume data generated by a series of CT or MR images had important significance on image reading and diagnosis. As a part of the DIOCM standard, WADO service defined how to access DICOM objects on the Web, but it didn't involve three-dimensional post-processing operations on the series images. This paper analyzed the technical features of three-dimensional post-processing operations on the volume data, and then designed and implemented a web service system for three-dimensional post-processing operations of medical images based on the WADO protocol. In order to improve the scalability of the proposed system, the business tasks and calculation operations were separated into two modules. As results, it was proved that the proposed system could support three-dimensional post-processing service of medical images for multiple clients at the same moment, which met the demand of accessing three-dimensional post-processing operations on the volume data on the web.

Characterization of image transfer patterns in a regional trauma network

Trauma Networks are currently founded in Germany to improve patient care of severely injured persons. To assure appropriate patient treatment in a short time, the transfer of radiological image data between the connected hospitals over the internet is an important method. This paper characterizes radiological image transfer patterns in a regional trauma network and analyzes various compression options. Within the "TraumaNetwork NorthWest" in Germany, the web-based platform "MedSix" was developed. MedSix is able to transfer DICOM-data quickly and easily between connected hospitals and can be directly connected to the local PACS. Audit data of the routine system between the 01.01.2012 and the 31.12.2012 were analyzed to identify typical characteristics of radiological image exchanges. Five different compression methods were compared by a simulation. MedSix has been used by 12 hospitals. 87 % of the transfers were uploaded within 15 min. Lossless compression is able to save about 50 % bandwidth. 82 % of the transfers have a data volume of less than 200 MB. Temporary accounts for non-regular users were used regularly. Most transfers were done from small to maximum care hospitals. It is feasible to substitute physical image exchange in a trauma network with electronic exchange of radiological images between the connected hospitals. Even large datasets are transferred within an acceptable time frame. Most transfers occur from small to large hospitals. The possibility of temporary accounts seems to be a key feature for the user acceptance.

A medical application integrating remote 3D visualization tools to access picture archiving and communication system on mobile devices

With computing capability and display size growing, the mobile device has been used as a tool to help clinicians view patient information and medical images anywhere and anytime. However, for direct interactive 3D visualization, which plays an important role in radiological diagnosis, the mobile device cannot provide a satisfactory quality of experience for radiologists. This paper developed a medical system that can get medical images from the picture archiving and communication system on the mobile device over the wireless network. In the proposed application, the mobile device got patient information and medical images through a proxy server connecting to the PACS server. Meanwhile, the proxy server integrated a range of 3D visualization techniques, including maximum intensity projection, multi-planar reconstruction and direct volume rendering, to providing shape, brightness, depth and location information generated from the original sectional images for radiologists. Furthermore, an algorithm that changes remote render parameters automatically to adapt to the network status was employed to improve the quality of experience. Finally, performance issues regarding the remote 3D visualization of the medical images over the wireless network of the proposed application were also discussed. The results demonstrated that this proposed medical application could provide a smooth interactive experience in the WLAN and 3G networks.

MIAPS: a web-based system for remotely accessing and presenting medical images

MIAPS (medical image access and presentation system) is a web-based system designed for remotely accessing and presenting DICOM image. MIAPS is accessed with web browser through the Internet. MIAPS provides four features: DICOM image retrieval, maintenance, presentation and output. MIAPS does not intent to replace sophisticated commercial and open source packages, but it provides a web-based solution for teleradiology and medical image sharing. The system has been evaluated by 39 hospitals in China for 10 months.

On the designing of a tamper resistant prescription RFID access control system

Recently, Chen et al. have proposed a novel tamper resistant prescription RFID access control system, published in the Journal of Medical Systems. In this paper we consider the security of the proposed protocol and identify some existing weaknesses. The main attack is a reader impersonation attack which allows an active adversary to impersonate a legitimate doctor, e.g. the patient's doctor, to access the patient's tag and change the patient prescription. The presented attack is quite efficient. To impersonate a doctor, the adversary should eavesdrop one session between the doctor and the patient's tag and then she can impersonate the doctor with the success probability of '1'. In addition, we present efficient reader-tag to back-end database impersonation, de-synchronization and traceability attacks against the protocol. Finally, we propose an improved version of protocol which is more efficient compared to the original protocol while provides the desired security against the presented attacks.

Request redirection paradigm in medical image archive implementation

It is widely recognized that the JPEG2000 facilitates issues in medical imaging: storage, communication, sharing, remote access, interoperability, and presentation scalability. Therefore, JPEG2000 support was added to the DICOM standard Supplement 61. Two approaches to support JPEG2000 medical image are explicitly defined by the DICOM standard: replacing the DICOM image format with corresponding JPEG2000 codestream, or by the Pixel Data Provider service, DICOM supplement 106. The latest one supposes two-step retrieval of medical image: DICOM request and response from a DICOM server, and then JPIP request and response from a JPEG2000 server. We propose a novel strategy for transmission of scalable JPEG2000 images extracted from a single codestream over DICOM network using the DICOM Private Data Element without sacrificing system interoperability. It employs the request redirection paradigm: DICOM request and response from JPEG2000 server through DICOM server. The paper presents programming solution for implementation of request redirection paradigm in a DICOM transparent manner.

Stream processing health card application

In this paper, we propose a data stream management system embedded to a smart card for handling and storing user specific summaries of streaming data coming from medical sensor measurements and/or other medical measurements. The data stream management system that we propose for a health card can handle the stream data rates of commonly known medical devices and sensors. It incorporates a type of context awareness feature that acts according to user specific information. The proposed system is cheap and provides security for private data by enhancing the capabilities of smart health cards. The stream data management system is tested on a real smart card using both synthetic and real data.

RFID-enabled healthcare applications, issues and benefits: an archival analysis (1997-2011)

In this paper, a comprehensive review of articles published between 1997 and 2011 in the Journal of Medical Systems (JMS) on RFID technology is presented. A total of 22 papers are analyzed using a classification framework that has three dimensions: RFID-enabled healthcare applications, RFID-enabled healthcare issues, and RFID-enabled healthcare benefits. In addition, an invitation sent to all authors of the papers accepted for the special issue on RFID for the JMS allows them to position their various papers within the classification framework. Finally, a list of future research directions is presented.