Current status and future advances of digital radiography and PACS

Three-Dimensional Adaptive Image Compression Concept for Medical Imaging: Application to Computed Tomography Angiography for Peripheral Arteries

Advances in computed tomography (CT) have resulted in a substantial increase in the size of datasets. We built a new concept of medical image compression that provides the best compromise between compression rate and image quality. The method is based on multiple contexts and regions-of-interest (ROI) defined according to the degree of clinical interest. High priority areas (primary ROIs) are assigned a lossless compression. Other areas (secondary ROIs and background) are compressed with moderate or heavy losses. The method is applied to a whole dataset of CT angiography (CTA) of the lower extremity vasculature. It is compared to standard lossy compression techniques in terms of quantitative and qualitative image quality. It is also compared to standard lossless compression techniques in terms of image size reduction and compression ratio. The proposed compression method met quantitative criteria for high-quality encoding. It obtained the highest qualitative image quality rating score, with a statistically significant difference compared to other methods. The average compressed image size was up to 61% lower compared to standard compression techniques, with a 9:1 compression ratio compared with original non-compressed images. Our new adaptive 3D compression method for CT images can save data storage space while preserving clinically relevant information.

APPLICABILITY OF THE COBB ANGLE MEASUREMENT IN IDIOPATHIC SCOLIOSIS USING SCANNED IMAGING

ABSTRACT Objectives: To compare the measurement of the Cobb angle on printed radiographs and on scanned radiographs viewed through the software "PixViewer". Methods: Preoperative radiographs of 23 patients were evaluated on printed films and through the software "PixViewer". The same evaluator, a spine surgeon, chose the proximal and distal limiting vertebrae of the main curve on printed radiographs, without identification of patients, and measured the Cobb angle based on these parameters. The same parameters and measurements were applied to scanned radiographs. The measurements were compared, as well as the choice of limiting vertebrae. Results: The average variation of the Cobb angle between methods was 1.48 ± 1.73°. The intraclass correlation coefficient (ICC) was 0.99, demonstrating excellent reproducibility. Conclusion: The Cobb method can be used to evaluate scoliosis through the "PixViewer" tool with the same reliability as the classic method on printed radiographs.

Grey-scale inversion improves detection of lung nodules

Objective The current study aims to establish whether detection of solitary pulmonary nodules can be improved by inverting the grey scale of posteroanterior (PA) chests. Methods 30 PA chest images were presented on 2 occasions to 16 senior radiologists on either primary or secondary class displays in the standard or inverted mode. 15 images within each group contained a single nodule positioned in a range of anatomical sites. A receiver operating characteristic (ROC) methodology was used to explore differences between the presentation modes. Results Improved ROC scores were evident with inverted (Az 0.77) compared with standard (Az 0.73) (p=0.02) images; however, this difference was seen only with the primary displays. The benefits seen are most likely owing to increased nodule luminance with the inverted images, particularly when using primary displays. Conclusion This study demonstrates that the inverted image can offer advantages in lung nodule detection over the standard presentation mode when images are viewed on high-specification viewing systems. The study has demonstrated that there is an improvement in the detectability of lung nodules on an inverted image with a primary display monitor that is not evident with secondary displays. This is likely to be the result of increased nodule luminance on primary displays when images are presented in the inverted mode.

Grey-scale inversion improves detection of lung nodules

OBJECTIVE

The current study aims to establish whether detection of solitary pulmonary nodules can be improved by inverting the grey scale of posteroanterior (PA) chests.

METHODS

30 PA chest images were presented on 2 occasions to 16 senior radiologists on either primary or secondary class displays in the standard or inverted mode. 15 images within each group contained a single nodule positioned in a range of anatomical sites. A receiver operating characteristic (ROC) methodology was used to explore differences between the presentation modes.

RESULTS

Improved ROC scores were evident with inverted (Az 0.77) compared with standard (Az 0.73) (p=0.02) images; however, this difference was seen only with the primary displays. The benefits seen are most likely owing to increased nodule luminance with the inverted images, particularly when using primary displays.

CONCLUSION

This study demonstrates that the inverted image can offer advantages in lung nodule detection over the standard presentation mode when images are viewed on high-specification viewing systems. The study has demonstrated that there is an improvement in the detectability of lung nodules on an inverted image with a primary display monitor that is not evident with secondary displays. This is likely to be the result of increased nodule luminance on primary displays when images are presented in the inverted mode.

Application of Multiprotocol Medical Imaging Communications and an Extended DICOM WADO Service in a Teleradiology Architecture

Multiprotocol medical imaging communication through the Internet is more flexible than the tight DICOM transfers. This paper introduces a modular multiprotocol teleradiology architecture that integrates DICOM and common Internet services (based on web, FTP, and E-mail) into a unique operational domain. The extended WADO service (a web extension of DICOM) and the other proposed services allow access to all levels of the DICOM information hierarchy as opposed to solely Object level. A lightweight client site is considered adequate, because the server site of the architecture provides clients with service interfaces through the web as well as invulnerable space for temporary storage, called as User Domains, so that users fulfill their applications' tasks. The proposed teleradiology architecture is pilot implemented using mainly Java-based technologies and is evaluated by engineers in collaboration with doctors. The new architecture ensures flexibility in access, user mobility, and enhanced data security.

Advanced networks and computing in healthcare

As computing and network capabilities continue to rise, it becomes increasingly important to understand the varied applications for using them to provide healthcare. The objective of this review is to identify key characteristics and attributes of healthcare applications involving the use of advanced computing and communication technologies, drawing upon 45 research and development projects in telemedicine and other aspects of healthcare funded by the National Library of Medicine over the past 12 years. Only projects publishing in the professional literature were included in the review. Four projects did not publish beyond their final reports. In addition, the authors drew on their first-hand experience as project officers, reviewers and monitors of the work. Major themes in the corpus of work were identified, characterizing key attributes of advanced computing and network applications in healthcare. Advanced computing and network applications are relevant to a range of healthcare settings and specialties, but they are most appropriate for solving a narrower range of problems in each. Healthcare projects undertaken primarily to explore potential have also demonstrated effectiveness and depend on the quality of network service as much as bandwidth. Many applications are enabling, making it possible to provide service or conduct research that previously was not possible or to achieve outcomes in addition to those for which projects were undertaken. Most notable are advances in imaging and visualization, collaboration and sense of presence, and mobility in communication and information-resource use.

Web-based diagnostic imaging service using XML forms

Traditionally, radiology has been conceived as a support department providing patient scanning services to the other clinical departments in a hospital. However, recent advancements in networking technology and related information systems such as picture archiving and communication system (PACS) and radiology information system (RIS) provide new opportunities for inventing different types of diagnostic imaging businesses such as teleradiology. In this article, we examined the business processes of currently operating imaging centers and proposed a prototype of an information system that can facilitate their workflows in a more efficient way. The principal component of our proposed system is a report management module built on extensible markup language (XML) technologies that allows much flexibility and convenience for both imaging technicians and radiologists.

Perceptually lossless medical image coding

A novel perceptually lossless coder is presented for the compression of medical images. Built on the JPEG 2000 coding framework, the heart of the proposed coder is a visual pruning function, embedded with an advanced human vision model to identify and to remove visually insignificant/irrelevant information. The proposed coder offers the advantages of simplicity and modularity with bit-stream compliance. Current results have shown superior compression ratio gains over that of its information lossless counterparts without any visible distortion. In addition, a case study consisting of 31 medical experts has shown that no perceivable difference of statistical significance exists between the original images and the images compressed by the proposed coder.

Classification and retrieval of medical images in an integrated healthcare environment

This work presents a new approach for classification and retrieval of echocardiographic images from textual information of the anatomical structures and diagnosis features. These textual attributes will be acquired from the electronic medical report generated in an integrated healthcare environment. The medical report is provided by a specialist in the area during the analysis of the medical image stored in a PACS environment. Such innovation guarantees a more accurate classifier and a better optimization of the medical work, since the medical report and the attributes for the medical image classifier will be created at the same time. The system is being developed in the University Hospital of the University of Brasilia.

Interactive image enhancement of CR and DR images

There is continual pressure on the radiology department to increase its productivity. Two important links to productivity in the computed/digital radiography (CR/DR) workflow chain are the postprocessing step by technologists and the primary diagnosis step by radiologists, who may apply additional image enhancements to aid them in diagnosis. With the large matrix size of CR and DR images and the computational complexity of these algorithms, it has been challenging to provide interactive image enhancement, particularly on full-resolution images. We have used a new programmable processor as the main computing engine of enhancement algorithms for CR or DR images. We have mapped these algorithms to the processor, maximally utilizing its architecture. On a 12-bit 2688 x 2688 image, we have achieved the execution time of 465A ms for adaptive unsharp masking, window/level, image rotate, and lookup table operations using a single processor, which represents at least an order of magnitude improvement compared to the response time of current systems. This kind of performance facilitates rapid computation with preset parameter values and/or enables truly interactive QA processing on radiographs by technologists. The fast response time of these algorithms would be especially useful in a real-time radiology setting, where the radiologist's waiting time in performing image enhancements before making diagnosis can be greatly reduced. We believe that the use of these processors for fast CR/DR image computing coupled with the seamless flow of images and patient data will enable the radiology department to achieve higher productivity.

Patient information extraction in digitized radiography

Digital imagery is gradually replacing the traditional radiograph with the development of digital radiography and film scanner. This report presents a new method to extract the patient information number (PIN) field automatically from the film-scanned image using image analysis technique. To evaluate the PIN field extraction algorithm, 2 formats of label acquired from 2 different hospitals are tested. Given the available films with no constraints on the way the labels are written and positioned, the correct extraction rates are 73% and 84%, respectively. This extracted PIN information can link with Radiology Information System (RIS) or Hospital Information System (HIS), and the image scanned from the film then can be filed into the database automatically. The efficiency this method offers can simplify greatly the image filing process and improve the user friendliness of the overall image digitization system. Moreover, compared with the bar code reader, it solves the automatic information input problem in a very economical way. The authors believe the success of this technique will benefit the development of the PACS (Picture Archiving and Communication System) and teleradiology.