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1.  Computerized Analysis of Pneumoconiosis in Digital Chest Radiography: Effect of Artificial Neural Network Trained with Power Spectra 
Journal of Digital Imaging  2010;24(6):1126-1132.
It is difficult for radiologists to classify pneumoconiosis with small nodules on chest radiographs. Therefore, we have developed a computer-aided diagnosis (CAD) system based on the rule-based plus artificial neural network (ANN) method for distinction between normal and abnormal regions of interest (ROIs) selected from chest radiographs with and without pneumoconiosis. The image database consists of 11 normal and 12 abnormal chest radiographs. These abnormal cases included five silicoses, four asbestoses, and three other pneumoconioses. ROIs (matrix size, 32 × 32) were selected from normal and abnormal lungs. We obtained power spectra (PS) by Fourier transform for the frequency analysis. A rule-based method using PS values at 0.179 and 0.357 cycles per millimeter, corresponding to the spatial frequencies of nodular patterns, were employed for identification of obviously normal or obviously abnormal ROIs. Then, ANN was applied for classification of the remaining normal and abnormal ROIs, which were not classified as obviously abnormal or normal by the rule-based method. The classification performance was evaluated by the area under the receiver operating characteristic curve (Az value). The Az value was 0.972 ± 0.012 for the rule-based plus ANN method, which was larger than that of 0.961 ± 0.016 for the ANN method alone (P ≤ 0.15) and that of 0.873 for the rule-based method alone. We have developed a rule-based plus pattern recognition technique based on the ANN for classification of pneumoconiosis on chest radiography. Our CAD system based on PS would be useful to assist radiologists in the classification of pneumoconiosis.
PMCID: PMC3222544  PMID: 21153856
Computer-aided diagnosis (CAD); Pneumoconiosis; Chest radiography; Power spectra; Artificial neural network
2.  Medical Decision-Making System of Ultrasound Carotid Artery Intima–Media Thickness Using Neural Networks 
Journal of Digital Imaging  2010;24(6):1112-1125.
The objective of this work is to develop and implement a medical decision-making system for an automated diagnosis and classification of ultrasound carotid artery images. The proposed method categorizes the subjects into normal, cerebrovascular, and cardiovascular diseases. Two contours are extracted for each and every preprocessed ultrasound carotid artery image. Two types of contour extraction techniques and multilayer back propagation network (MBPN) system have been developed for classifying carotid artery categories. The results obtained show that MBPN system provides higher classification efficiency, with minimum training and testing time. The outputs of decision support system are validated with medical expert to measure the actual efficiency. MBPN system with contour extraction algorithms and preprocessing scheme helps in developing medical decision-making system for ultrasound carotid artery images. It can be used as secondary observer in clinical decision making.
PMCID: PMC3222553  PMID: 21181487
US carotid artery image analysis; Contour extraction; Multilayer back propagation network; Neural network classifier; Carotid artery classification; Medical decision-making system; Digital image processing; Image segmentation; Decision support techniques; Neural networks; Carotid artery
3.  Dicoogle - an Open Source Peer-to-Peer PACS 
Journal of Digital Imaging  2010;24(5):848-856.
Picture Archiving and Communication Systems (PACS) have been widely deployed in healthcare institutions, and they now constitute a normal commodity for practitioners. However, its installation, maintenance, and utilization are still a burden due to their heavy structures, typically supported by centralized computational solutions. In this paper, we present Dicoogle, a PACS archive supported by a document-based indexing system and by peer-to-peer (P2P) protocols. Replacing the traditional database storage (RDBMS) by a documental organization permits gathering and indexing data from file-based repositories, which allows searching the archive through free text queries. As a direct result of this strategy, more information can be extracted from medical imaging repositories, which clearly increases flexibility when compared with current query and retrieval DICOM services. The inclusion of P2P features allows PACS internetworking without the need for a central management framework. Moreover, Dicoogle is easy to install, manage, and use, and it maintains full interoperability with standard DICOM services.
PMCID: PMC3180530  PMID: 20981467
PACS; Digital Imaging and Communications in Medicine (DICOM); Medical imaging; Peer-to-peer; Computer communication networks; Open source; PACS implementation; Information storage and retrieval
4.  A Novel Medical Image Quality Index 
Journal of Digital Imaging  2010;24(5):874-882.
A novel medical image quality index using grey relational coefficient calculation is proposed in this study. Three medical modalities, DR, CT and MRI, using 30 or 60 images with a total of 120 images used for experimentation. These images were first compressed at ten different compression ratios (10 ∼ 100) using a medical image compression algorithm named JJ2000. Following that, the quality of the reconstructed images was evaluated using the grey relational coefficient calculation. The results were shown consistent with popular objective quality metrics. The impact of different image aspects on four grey relational coefficient methods were further tested. The results showed that these grey relational coefficients have different slopes but very high consistency for various image areas. Nagai’s grey relational coefficient was chosen in this study because of higher calculation speed and sensitivity. A comparison was also made between this method and other windows-based objective metrics for various window sizes. Studies found that the grey relational coefficient results are less sensitive to window size changes. The performance of this index is better than some windows-based objective metrics and can be used as an image quality index.
PMCID: PMC3180531  PMID: 21104000
Image compression; Image quality analysis; JPEG2000
5.  Aging and Quality Control of Color LCDs for Radiologic Imaging 
Journal of Digital Imaging  2010;24(5):828-832.
Our practice has long been concerned with the effects of display quality, including color accuracy and matching among paired color displays. Three years of data have been collected on the historical behavior of color stability on our clinical displays. This has permitted an analysis of the color-aging behavior of those displays over that time. The results of that analysis show that all displays tend to yellow over time, but that they do so together. That is, neither the intra- nor inter-display color variances observed at initial deployment diverge over time as measured by a mean radial distance metric in color space (Commission Internationale d’Eclairage L’, u’, v’ 1976). The consequence of this result is that color displays that are matched at deployment tend to remain matched over their lifetime even as they collectively yellow.
PMCID: PMC3180532  PMID: 20978919
Digital display; Diagnostic image quality; Diagnostic display; Monitors
6.  A Pilot Study on Using Eye Tracking to Understand Assessment of Surgical Outcomes from Clinical Photography 
Journal of Digital Imaging  2010;24(5):778-786.
Appearance changes resulting from breast cancer treatment impact the quality of life of breast cancer survivors, but current approaches to evaluating breast characteristics are very limited. It is challenging, even for experienced plastic surgeons, to describe how different aspects of breast morphology impact overall assessment of esthetics. Moreover, it is difficult to describe what they are looking for in a manner that facilitates quantification. The goal of this study is to assess the potential of using eye-tracking technology to understand how plastic surgeons assess breast morphology by recording their gaze path while they rate physical characteristics of the breasts, e.g., symmetry, based on clinical photographs. In this study, dwell time, transition frequency, dwell sequence conditional probabilities, and dwell sequence joint probabilities were analyzed across photographic poses and three observers. Dwell-time analysis showed that all three surgeons spent the majority of their time on the anterior–posterior (AP) views. Similarly, transition frequency analysis between regions showed that there were substantially more transitions between the breast regions in the AP view, relative to the number of transitions between other views. The results of both the conditional and joint probability analyses between the breast regions showed that the highest probabilities of transitions were observed between the breast regions in the AP view (APRB, APLB) followed by the oblique views and the lateral views to complete evaluation of breast surgical outcomes.
PMCID: PMC3180533  PMID: 20852914
Breast neoplasm; Eye movements; Biomedical image analysis; Decision support; Evaluation research
7.  Development of a Research Dedicated Archival System (TARAS) in a University Hospital 
Journal of Digital Imaging  2010;24(5):864-873.
Recent healthcare policies have influenced the manner in which patient data is handled in research projects, and the regulations concerning protected health information have become significantly tighter. Thus, new procedures are needed to facilitate research while protecting the confidentiality of patient data and ensuring the integrity of clinical work in the expanding environment of electronic files and databases. We have addressed this problem in a university hospital setting by developing the Tampere Research Archival System (TARAS), an extensive data warehouse for research purposes. This dynamic system includes numerous integrated and pseudonymized imaging studies and clinical data. In a pilot study on asthma patients, we tested and improved the functionality of the data archival system. TARAS is feasible to use in retrieving, analyzing, and processing both image and non-image data. In this paper, we present a detailed workflow of the implementation process of the data warehouse, paying special attention to administrative, ethical, practical, and data security concerns. The establishment of TARAS will enhance and accelerate research practice at Tampere University Hospital, while also improving the safety of patient information as well as the prospects for national and international research collaboration. We hope that much can be learned from our experience of planning, designing, and implementing a research data warehouse combining imaging studies and medical records in a university hospital.
PMCID: PMC3180537  PMID: 21042830
PACS; Research PACS; Hospital information systems; Research Archival System; TARAS; Medical research; Large scale; Pseudonymization
8.  Radiology IT: Applications Integration vs. Consolidation 
Journal of Digital Imaging  2010;24(5):814-822.
The question of whether Radiology IT systems should be composed of multiple applications integrated using standard data exchange protocols, such as DICOM and HL7, or implemented using consolidation of applications and systems has been debated for the past 30 years. The adequacy of the former approach has become a burning issue because the demands on Radiology IT systems have increased greatly. We report here on the experience of the Radiology Information Technology (IT) implementation at the Memorial Sloan-Kettering Cancer Center (MSKCC) over the past 11 years; during this time, the weekly image accumulation rate increased from 100,000 to 2,000,000 images. During the implementation period, major difficulties were encountered, largely as a result of the inadequacies of the Radiology IT architecture widely used in the healthcare industry. The approach we chose to correct some of these difficulties has been consolidation of some of the multiple systems and applications. Three examples of systems consolidation are discussed: (1) converting a dual-tier image storage system to a single tier, (2) consolidation of Mammography reading into PACS, and (3) enabling 3D visualization and analysis on the PACS workstation. Nevertheless, substantial research and development are needed in order to proceed with more extensive systems consolidation and, thus, a more manageable IT installation.
PMCID: PMC3180538  PMID: 20976613
PACS; Radiology Information System (RIS); Radiology reporting; Digital Imaging and Communications in Medicine (DICOM); Health Level 7 (HL7); Radiology workflow; Cost-effectiveness; Databases; Imaging informatics; Radiology workstation
9.  Imaging Facilities for Basic Medical Units: A Case in the State of Guerrero, Mexico 
Journal of Digital Imaging  2010;24(5):857-863.
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.
PMCID: PMC3180540  PMID: 21042831
Medical imaging; Healthcare systems; Medical technology assessment; PACS; Diagnostic imaging; Digital imaging; Digital radiography; Medical economics; Health technology; Radiology department; Hospital
10.  Human–Computer Interaction in Radiotherapy Target Volume Delineation: A Prospective, Multi-institutional Comparison of User Input Devices 
Journal of Digital Imaging  2010;24(5):794-803.
The purpose of this study was the prospective comparison of objective and subjective effects of target volume region of interest (ROI) delineation using mouse–keyboard and pen–tablet user input devices (UIDs). The study was designed as a prospective test/retest sequence, with Wilcoxon signed rank test for matched-pair comparison. Twenty-one physician-observers contoured target volume ROIs on four standardized cases (representative of brain, prostate, lung, and head and neck malignancies) twice: once using QWERTY keyboard/scroll-wheel mouse UID and once with pen–tablet UID (DTX2100, Wacom Technology Corporation, Vancouver, WA, USA). Active task time, ROI manipulation task data, and subjective survey data were collected. One hundred twenty-nine target volume ROI sets were collected, with 62 paired pen–tablet/mouse–keyboard sessions. Active contouring time was reduced using the pen–tablet UID, with mean ± SD active contouring time of 26 ± 23 min, compared with 32 ± 25 with the mouse (p ≤ 0.01). Subjective estimation of time spent was also reduced from 31 ± 26 with mouse to 27 ± 22 min with the pen (p = 0.02). Task analysis showed ROI correction task reduction (p = 0.045) and decreased panning and scrolling tasks (p < 0.01) with the pen–tablet; drawing, window/level changes, and zoom commands were unchanged (p = n.s.) Volumetric analysis demonstrated no detectable differences in ROI volume nor intra- or inter-observer volumetric coverage. Fifty-two of 62 (84%) users preferred the tablet for each contouring task; 5 of 62 (8%) denoted no preference, and 5 of 62 (8%) chose the mouse interface. The pen–tablet UID reduced active contouring time and reduced correction of ROIs, without substantially altering ROI volume/coverage.
Electronic supplementary material
The online version of this article (doi:10.1007/s10278-010-9341-2) contains supplementary material, which is available to authorized users.
PMCID: PMC3180541  PMID: 20978922
User interface; User–computer interface; Workflow; Workflow reengineering; Radiation oncology; Radiotherapy; Observer variation; Observer performance; Imaging informatics; Human–computer interaction
11.  Authentication and Self-Correction in Sequential MRI Slices 
Journal of Digital Imaging  2010;24(5):943-949.
One of the new challenges of Information Technology in the medical world is the protection and authentication of a variety of digital medical files, datasets, and images. In this work, the ability of magnetic resonance imaging (MRI) slice sequences to hide digital data is investigated and more specifically the case that the hidden data are the regions of interest (ROI) of the MRI slices. The regions of non-interest (RONI) are used as cover. The hiding capacity of the whole sequence is taken into account. Any ROI-targeted tampering attempt can be detected, and the original image can be self-restored (under certain conditions) by extracting the ROI from the RONI.
PMCID: PMC3180543  PMID: 20945077
Medical imaging; MRI; ROI; Authentication; Self-correction; Integrity; JPEG2000
12.  Accuracy of CBCT Measurements of a Human Skull 
Journal of Digital Imaging  2010;24(5):787-793.
The purpose of this study is to assess the accuracy and reproducibility of cone-beam computed tomography (CBCT) measurements of a human dry skull by comparing them to direct digital caliper measurements. Heated gutta-percha was used to mark 13 specific distances on a human skull, and the distances were directly measured using a digital caliper and on CBCT images obtained with Iluma (3M Imtec, OK, USA) and 3D Accuitomo 170 (3D Accuitomo; J Morita Mfg. Corp., Kyoto, Japan) CBCT imaging systems. Iluma images were obtained at 120 kVp and 3.8 mA and reconstructed using voxel sizes of 0.2 and 0.3 mm3. Accuitomo images were obtained at 60 kVp and 2 mA and a voxel size of 0.250 mm3. In addition, 3-D reconstructions were produced from images obtained from both systems. All measurements were made independently by three trained observers and were repeated after an interval of 1 week. Agreement between observers and image type was assessed by calculating Pearson correlation coefficients, with a level of significance set at p < 0.05. Pearson correlation coefficients between readings ranged from 0.995 to 1 for all image types. Correlations among observers were also very high, ranging from 0.992 to 1 for the first reading and from 0.992 to 1 for the second reading for the different image types. All CBCT image measurements were identical and highly correlated with digital caliper measurements. Accuracy of measurements of various distances on a human skull obtained from different CBCT units and image types is comparable to that of digital caliper measurements.
PMCID: PMC3180546  PMID: 20857166
CBCT; Direct measurement; Radiography; 3-D imaging (imaging, three-dimensional); 3-D reconstruction; Automated measurement; Computed tomography
13.  Using Keynote to Present Radiology Images 
Journal of Digital Imaging  2010;24(5):844-847.
Numerous articles have offered instructions for working with advanced radiology images in Microsoft PowerPoint (Redmond, WA); however, no articles have detailed instructions to do the same on alternative presentation software. Apple Macintosh (Cupertino, CA) computers are gaining popularity with many radiologists, due in part to the availability of a powerful, free, open-source Digital Imaging and Communications in Medicine (DICOM) viewing and manipulating software OsiriX ( Apple’s own presentation software, Keynote, is particularly effective in dealing with medical images and cine clips. This article demonstrates how to use Apple’s Keynote software to present radiology images and scrollable image stacks, without third-party add-on software. The article also illustrates how to compress media files and protect patient information in Keynote presentations. Lastly, it addresses the steps to converting between PowerPoint and Keynote file formats. Apple’s Keynote software enables quick and efficient addition of multiple static images or scrollable image stacks, compression of media files, and removal of patient information. These functions can be accomplished by inexperienced users with no software modifications.
PMCID: PMC3180549  PMID: 20978920
Computers in medicine; Radiology Information Systems (RIS); Radiology teaching file; Image processing; Image display; Productivity; Keynote
14.  Occlusal Caries Depth Measurements Obtained by Five Different Imaging Modalities 
Journal of Digital Imaging  2010;24(5):804-813.
The study aimed to assess the accuracy and reproducibility of occlusal caries depth measurements obtained from different imaging modalities. The study comprised 21 human mandibular molar teeth with occlusal caries. Teeth were imaged using film, CCD, two different cone-beam computerized tomography (CBCT) units and a microcomputer tomography (micro-CT). Thereafter, each tooth was serially sectioned, and the section with the deepest carious lesion was scanned using a high-resolution scanner. Each image set was separately viewed by three oral radiologists. Images were viewed randomly, and each set was viewed twice. Lesion depth was measured on film images using a digital caliper, on CCD and CBCT images using built-in measurement tools, on micro-CT images using the Mimics software program, and on histological images using AxioVision Rel. 4.7. Intra- and inter-rater reliabilities were assessed according to the Bland/Altman method by calculating Intraclass Correlation Coefficients (ICCs). Mean/median values obtained with intraoral systems were lower than those obtained with 3-D and histological images for all observers and both readings. Intra-observer ICC values for all observers were highest for histology and micro-CT. In addition, intra-observer ICC values were higher for histology and CBCT than for histology and intra-oral methods. Inter-observer ICC values for first and second readings were high for all observers. No differences in repeatability were found between Accuitomo and Iluma CBCT images or between intra-oral film and CCD images. Micro-CT was found to be the best imaging method for the ex vivo measurement of occlusal caries depth. In addition, both CBCT units performed similarly and better than intra-oral modalities.
PMCID: PMC3180550  PMID: 21116675
Occlusal caries; Depth measurement; CBCT; Micro-CT; Radiography
15.  Rigid Registration of Medical Images Using 1D and 2D Binary Projections 
Journal of Digital Imaging  2010;24(5):913-925.
Image registration is a necessary procedure in everyday clinical practice. Several techniques for rigid and non-rigid registration have been developed and tested and the state-of-the-art is evolving from the research setting to incorporate image registration techniques into clinically useful tools. In this paper, we develop a novel rigid medical image registration technique which incorporates binary projections. This technique is tested and compared to the standard mutual information (MI) methods. Results show that the method is significantly more accurate and robust compared to MI methods. The accuracy is well below 0.5° and 0.5 mm. This method introduces two more improvements over MI methods: (1)for 2D registration with the use of 1D binary projections, we use minimal interpolation; and (2) for 3D registration with the use of 2D binary projections the method converges to stable final positions, independent of the initial misregistration.
Electronic supplementary material
The online version of this article (doi:10.1007/s10278-010-9352-z) contains supplementary material, which is available to authorized users.
PMCID: PMC3180551  PMID: 21086018
Medical image registration; Binary projections; Interpolation; Convergence
16.  Creation and Storage of Standards-based Pre-scanning Patient Questionnaires in PACS as DICOM Objects 
Journal of Digital Imaging  2010;24(5):823-827.
Radiology departments around the country have completed the first evolution to digital imaging by becoming filmless. The next step in this evolution is to become truly paperless. Both patient and non-patient paperwork has to be eliminated in order for this transition to occur. A paper-based set of patient pre-scanning questionnaires were replaced with web-based forms for use in an outpatient imaging center. We discuss this process by which questionnaire elements are converted into SNOMED-CT terminology concepts, stored for future use, and sent to PACS in Digital Imaging and Communications in Medicine (DICOM) format to be permanently stored with the relevant study in the DICOM image database.
PMCID: PMC3180552  PMID: 20976611
Paperless; Pseudo paperless; Filmless; SNOMED-CT; Data mining; Clinical workflow; Data collection
17.  Development of Subject-Specific Geometric Spine Model through Use of Automated Active Contour Segmentation and Kinematic Constraint-Limited Registration 
Journal of Digital Imaging  2010;24(5):926-942.
This paper describes the development of a patient-specific spine model through use of active contour segmentation and registration of intraoperative imaging of porcine vertebra augmented with kinematic constraints. The geometric active contours are fully automated and lead to a discrete representation of the image segmentation results. After determining errors within the segmentations, application of reliability theory allows the selection of active contour parameters to obtain best-fit segmentations from a stack of 2D images. The segmented images are then used in conjunction with C-arm fluoroscope images to simulate the result of intraoperative patient-specific model registration including patient and/or structure motion between preoperative and intraoperative scans. The results are validated through comparison of the error within the patient-specific model generated through use of the C-arm images with a model acquired directly from MRI images of the spine after motion. The results are applicable to the development of a wide variety of patient-specific geometric and biomechanical models.
PMCID: PMC3180553  PMID: 20882395
Segmentation; template geometry; patient-specific model; spine; active contour; fluoroscopy; kinematic constraints; imaging; image error; registration
18.  Using JPEG 2000 Interactive Protocol to Stream a Large Image or a Large Image Set 
Journal of Digital Imaging  2010;24(5):833-843.
The electronic health record (EHR) is expected to improve the quality of care by enabling access to relevant information at the diagnostic decision moment. During deployment efforts for including images in the EHR, a main challenge has come up from the need to compare old images with current ones. When old images reside in a different system, they need to be imported for visualization which leads to a problem related to persistency management and information consistency. A solution consisting in avoiding image import is achievable with image streaming. In this paper we present, evaluate, and discuss two medical-specific streaming use cases: displaying a large image such as a digital mammography image and displaying a large set of relatively small images such as a large CT series.
PMCID: PMC3180554  PMID: 20978921
Medical imaging; Electronic health record; Image communication; Image streaming; JPIP; JPEG 2000
19.  A Method for Computing General Sacroiliac Screw Corridors Based on CT Scans of the Pelvis 
Journal of Digital Imaging  2010;24(4):665-671.
Sacroiliac (SI) joint dislocations and sacral fractures of the pelvis can be stabilized by SI screws; however, screw insertion into a sacral isthmus region is risky for the adjacent neurovascular structures. Therefore, shape analyses of general SI screw corridors or safety zones are of great surgical interest; however, before such analyses can be conducted, a method for computing 3D models of general SI corridors from routine clinical computed tomography (CT) scans has to be developed. This work describes a method for determining general corridors in pelvic CT data for accurate screw placement into the first sacral body. The method is implemented with the computer language C++. The pelvic CT data are preprocessed before the presented algorithm computes a model of the 3D corridor volume. Additionally, the two most important parameters of the algorithm, the raster step and the virtual SI screw diameter, have been characterized. The result of the work is an algorithm for computing general SI screw corridors and its implementation. Additionally the influences of two important parameters, the raster step and the SI screw diameter, on corridor volume precision and computation time have been quantified for the test sample. We conclude that the method can be used in further corridor shape analyses with a large number of pelvic CT data sets for investigating general SI screw corridors and clinical consequences for the placements of the screws. Implementation of the presented software algorithm could also enhance performance of computer-assisted surgery in the near future.
PMCID: PMC3138925  PMID: 20725760
3D imaging; image analysis; bone and bones; computed tomography; image processing; software design; pelvis
20.  Automatic Monitoring of Localized Skin Dose with Fluoroscopic and Interventional Procedures 
Journal of Digital Imaging  2010;24(4):626-639.
This software tool locates and computes the intensity of radiation skin dose resulting from fluoroscopically guided interventional procedures. It is comprised of multiple modules. Using standardized body specific geometric values, a software module defines a set of male and female patients arbitarily positioned on a fluoroscopy table. Simulated X-ray angiographic (XA) equipment includes XRII and digital detectors with or without bi-plane configurations and left and right facing tables. Skin dose estimates are localized by computing the exposure to each 0.01 × 0.01 m2 on the surface of a patient irradiated by the X-ray beam. Digital Imaging and Communications in Medicine (DICOM) Structured Report Dose data sent to a modular dosimetry database automatically extracts the 11 XA tags necessary for peak skin dose computation. Skin dose calculation software uses these tags (gantry angles, air kerma at the patient entrance reference point, etc.) and applies appropriate corrections of exposure and beam location based on each irradiation event (fluoroscopy and acquistions). A physicist screen records the initial validation of the accuracy, patient and equipment geometry, DICOM compliance, exposure output calibration, backscatter factor, and table and pad attenuation once per system. A technologist screen specifies patient positioning, patient height and weight, and physician user. Peak skin dose is computed and localized; additionally, fluoroscopy duration and kerma area product values are electronically recorded and sent to the XA database. This approach fully addresses current limitations in meeting accreditation criteria, eliminates the need for paper logs at a XA console, and provides a method where automated ALARA montoring is possible including email and pager alerts.
PMCID: PMC3138926  PMID: 20706859
Peak skin dose; sentinal event; DICOM structured report dose; patient entrance reference point; fluoroscopy; interventional radiology; Joint Commission (JC); radiation dose; Digital Imaging and Communications in Medicine (DICOM)
21.  A Mobile Tele-Radiology Imaging System with JPEG2000 for an Emergency Care 
Journal of Digital Imaging  2010;24(4):709-718.
The aim of this study was to design a tele-radiology imaging system for rapid emergency care via mobile networks and to assess the diagnostic feasibility of the Joint Photographic Experts Group 2000 (JPEG2000) radiological imaging using portable devices. Rapid patient information and image exchange is helpful to make clinical decisions. We assessed the usefulness of the mobile tele-radiology system by measuring both a quantitative method, PNSR calculation, for image qualities, and its transmission time via mobile networks in different mobile networks, respectively; code division multiple access evolution-data optimized, wireless broadband, and high-speed downlink packet access; and the feasibility of the JPEG2000 computed tomography (CT) images by qualitatively assessing with the Alberta stroke program early CT score method with 12 CT image cases (seven normal and five abnormal cases). We found that the quality of the JPEG2000 radiological images was satisfied quantitatively and was judged as acceptable qualitatively at 5:1 and 10:1 compression levels for the mobile tele-radiology imaging system. The JPEG2000-format radiological images achieved a fast transmission while maintaining a diagnosis quality on a portable device via mobile networks. Unfortunately, a PDA device, having a limited screen resolution, posed difficulties in reviewing the JPEG2000 images regardless of the compression levels. An ultra mobile PC was preferable to study the medical image. The mobile tele-radiology imaging systems supporting JPEG2000 image transmission can be applied to actual emergency care services under mobile computing environments.
PMCID: PMC3138927  PMID: 20824300
Mobile tele-radiology; JPEG2000; radiological CT image; emergency care
22.  Three-dimensional Elastic Image Registration Based on Strain Energy Minimization: Application to Prostate Magnetic Resonance Imaging 
Journal of Digital Imaging  2010;24(4):573-585.
The use of magnetic resonance (MR) imaging in conjunction with an endorectal coil is currently the clinical standard for the diagnosis of prostate cancer because of the increased sensitivity and specificity of this approach. However, imaging in this manner provides images and spectra of the prostate in the deformed state because of the insertion of the endorectal coil. Such deformation may lead to uncertainties in the localization of prostate cancer during therapy. We propose a novel 3-D elastic registration procedure that is based on the minimization of a physically motivated strain energy function that requires the identification of similar features (points, curves, or surfaces) in the source and target images. The Gauss–Seidel method was used in the numerical implementation of the registration algorithm. The registration procedure was validated on synthetic digital images, MR images from prostate phantom, and MR images obtained on patients. The registration error, assessed by averaging the displacement of a fiducial landmark in the target to its corresponding point in the registered image, was 0.2 ± 0.1 pixels on synthetic images. On the prostate phantom and patient data, the registration errors were 1.0 ± 0.6 pixels (0.6 ± 0.4 mm) and 1.8 ± 0.7 pixels (1.1 ± 0.4 mm), respectively. Registration also improved image similarity (normalized cross-correlation) from 0.72 ± 0.10 to 0.96 ± 0.03 on patient data. Registration results on digital images, phantom, and prostate data in vivo demonstrate that the registration procedure can be used to significantly improve both the accuracy of localized therapies such as brachytherapy or external beam therapy and can be valuable in the longitudinal follow-up of patients after therapy.
PMCID: PMC3138929  PMID: 20552248
Elastic registration; strain energy minimization; magnetic resonance imaging; prostate; endorectal coil
24.  Non-Clinical Errors Using Voice Recognition Dictation Software for Radiology Reports: A Retrospective Audit 
Journal of Digital Imaging  2010;24(4):724-728.
The purpose of this study is to ascertain the error rates of using a voice recognition (VR) dictation system. We compared our results with several other articles and discussed the pros and cons of using such a system. The study was performed at the Southern Health Department of Diagnostic Imaging, Melbourne, Victoria using the GE RIS with Powerscribe 3.5 VR system. Fifty random finalized reports from 19 radiologists obtained between June 2008 and November 2008 were scrutinized for errors in six categories namely, wrong word substitution, deletion, punctuation, other, and nonsense phrase. Reports were also divided into two categories: computer radiography (CR = plain film) and non-CR (ultrasound, computed tomography, magnetic resonance imaging, nuclear medicine, and angiographic examinations). Errors were divided into two categories, significant but not likely to alter patient management and very significant with the meaning of the report affected, thus potentially affecting patient management (nonsense phrase). Three hundred seventy-nine finalized CR reports and 631 non-CR finalized reports were examined. Eleven percent of the reports in the CR group had errors. Two percent of these reports contained nonsense phrases. Thirty-six percent of the reports in the non-CR group had errors and out of these, 5% contained nonsense phrases. VR dictation system is like a double-edged sword. Whilst there are many benefits, there are also many pitfalls. We hope that raising the awareness of the error rates will help in our efforts to reduce error rates and strike a balance between quality and speed of reports generated.
PMCID: PMC3138931  PMID: 20976612
Voice recognition; Reporting; Productivity; Speech recognition; Workflow; Radiology reporting
25.  Clinical Utility of Temporal Subtraction Images in Successive Whole-Body Bone Scans: Evaluation in a Prospective Clinical Study 
Journal of Digital Imaging  2010;24(4):680-687.
In order to aid radiologists’ routine work for interpreting bone scan images, we developed a computerized method for temporal subtraction (TS) images which can highlight interval changes between successive whole-body bone scans, and we performed a prospective clinical study for evaluating the clinical utility of the TS images. We developed a TS image server which includes an automated image-retrieval system, an automated image-conversion system, an automated TS image-producing system, a computer interface for displaying and evaluating TS images with five subjective scales, and an automated data-archiving system. In this study, the radiologist could revise his/her report after reviewing the TS images if the findings on the TS image were confirmed retrospectively on our clinical picture archiving and communication system. We had 256 consenting patients of whom 143 had two or more whole-body bone scans available for TS images. In total, we obtained TS images successfully in 292 (96.1%) pairs and failed to produce TS images in 12 pairs. Among the 292 TS studies used for diagnosis, TS images were considered as “extremely beneficial” or “somewhat beneficial” in 247 (84.6%) pairs, as “no utility” in 44 pairs, and as “somewhat detrimental” in only one pair. There was no TS image for any pairs that was considered “extremely detrimental.” In addition, the radiologists changed their initial reported impression in 18 pairs (6.2%). The benefit to the radiologist of using TS images in the routine interpretation of successive whole-body bone scans was significant, with negligible detrimental effects.
PMCID: PMC3138932  PMID: 20730471
Bone scintigram; whole-body scan; interval change; temporal subtraction image; prospective clinical study

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