Comparison of conventional and computed radiography: assessment of image quality and reader performance in skeletal extremity trauma

Digital Imaging and PACS: An Update

The instant and simultaneous availability of radiologic examinations has long been of interest to referring clinicians, and certainly to radiologists, within and outside of the hospital. In daily clinical routine, the term “film management problem” has been used to describe a lack of access to this essential part of clinical information. Comprehensive picture archiving and communication systems (PACSs) have been proposed and implemented only within few institutions. This article discusses some of the most important standards, and technical and practical aspects of digital imaging and PACS.

Tracking eye gaze during interpretation of endoluminal three-dimensional CT colonography: visual perception of experienced and inexperienced readers

PURPOSE

To identify and compare key stages of the visual process in experienced and inexperienced readers and to examine how these processes are used to search a moving three-dimensional ( 3D three-dimensional ) image and their relationship to false-negative errors.

MATERIALS AND METHODS

Institutional review board research ethics approval was granted to use anonymized computed tomographic (CT) colonographic data from previous studies and to obtain eye-tracking data from volunteers. Sixty-five radiologists (27 experienced, 38 inexperienced) interpreted 23 endoluminal 3D three-dimensional CT colonographic videos. Eye movements were recorded by using eye tracking with a desk-mounted tracker. Readers indicated when they saw a polyp by clicking a computer mouse. Polyp location and boundary on each video frame were quantified and gaze data were related to the polyp boundary for each individual reader and case. Predefined metrics were quantified and used to describe and compare visual search patterns between experienced and inexperienced readers by using multilevel modeling.

RESULTS

Time to first pursuit was significantly shorter in experienced readers (hazard ratio, 1.22 [95% confidence interval: 1.04, 1.44]; P = .017) but other metrics were not significantly different. Regardless of expertise, metrics such as assessment, identification period, and pursuit times were extended in videos where polyps were visible on screen for longer periods of time. In 97% (760 of 787) of observations, readers correctly pursued polyps.

CONCLUSION

Experienced readers had shorter time to first eye pursuit, but many other characteristics of eye tracking were similar between experienced and inexperienced readers. Readers pursued polyps in 97% of observations, which indicated that errors during interpretation of 3D three-dimensional CT colonography in this study occurred in either the discovery or the recognition phase, but rarely in the scanning phase of radiologic image inspection.

The posterior impingement view: an alternative conventional projection to detect bony posterior ankle impingement

PURPOSE

The purpose of the current study was to clinically evaluate the diagnostic value of the new posterior impingement (PIM) view in the detection of an os trigonum, compared with the standard lateral view, using computed tomography (CT) as a reference standard.

METHODS

Three observers, 2 experienced (orthopaedic surgeon and radiologist) and one inexperienced (resident), independently scored 142 radiographic images for the presence of an os trigonum. The diagnostic performance was assessed using the computed tomographic scan as the reference standard. Accuracy, sensitivity, specificity, positive predicted value (PPV), and negative predicted value (NPV) were calculated.

RESULTS

The PIM view had significantly superior accuracy compared with the lateral view for each observer: orthopaedic surgeon, PIM view = 90 versus lateral view = 75 (P = .013); radiologist, PIM view = 80 versus lateral view = 64 (P = .019); resident, PIM view = 90 versus lateral view = 79 (P = .039). The mean sensitivity and specificity of the lateral view for all observers was 50% and 81%, respectively. For the PIM view, this was 78% and 89%, respectively. The PPV was 50% for the lateral view and 70% for the PIM view. The NPV was 84% for the lateral view and 93% for the PIM view.

CONCLUSIONS

The PIM view has significantly superior diagnostic accuracy compared with the conventional lateral view in the detection of an os trigonum. In cases of symptomatic posterior ankle impingement, we advise that a PIM view be used instead of or in addition to the standard lateral view for detection of posterior talar pathologic conditions. LEVEL OF 

EVIDENCE

Level II, development of diagnostic criteria on basis of consecutive patients with universally applied reference gold standard.

Human Factors and Human-Computer Considerations in Teleradiology and Telepathology

Radiology and pathology are unique among other clinical specialties that incorporate telemedicine technologies into clinical practice, as, for the most part in traditional practice, there are few or no direct patient encounters. The majority of teleradiology and telepathology involves viewing images, which is exactly what occurs without the "tele" component. The images used are generally quite large, require dedicated displays and software for viewing, and present challenges to the clinician who must navigate through the presented data to render a diagnostic decision or interpretation. This digital viewing environment is very different from the more traditional reading environment (i.e., film and microscopy), necessitating a new look at how to optimize reading environments and address human factors issues. This paper will review some of the key components that need to be optimized for effective and efficient practice of teleradiology and telepathology using traditional workstations as well as some of the newer mobile viewing applications.

Current perspectives in medical image perception

Medical images constitute a core portion of the information a physician utilizes to render diagnostic and treatment decisions. At a fundamental level, this diagnostic process involves two basic processes: visually inspecting the image (visual perception) and rendering an interpretation (cognition). The likelihood of error in the interpretation of medical images is, unfortunately, not negligible. Errors do occur, and patients' lives are impacted, underscoring our need to understand how physicians interact with the information in an image during the interpretation process. With improved understanding, we can develop ways to further improve decision making and, thus, to improve patient care. The science of medical image perception is dedicated to understanding and improving the clinical interpretation process.

Does PACS improve diagnostic accuracy in chest radiograph interpretations in clinical practice?

OBJECTIVES

To assess the impact of a Picture Archiving and Communication System (PACS) on the diagnostic accuracy of the interpretation of chest radiology examinations in a "real life" radiology setting.

MATERIALS AND METHODS

During a period before PACS was introduced to radiologists, when images were still interpreted on film and reported on paper, images and reports were also digitally stored in an image database. The same database was used after the PACS introduction. This provided a unique opportunity to conduct a blinded retrospective study, comparing sensitivity (the main outcome parameter) in the pre and post-PACS periods. We selected 56 digitally stored chest radiograph examinations that were originally read and reported on film, and 66 examinations that were read and reported on screen 2 years after the PACS introduction. Each examination was assigned a random number, and both reports and images were scored independently for pathological findings. The blinded retrospective score for the original reports were then compared with the score for the images (the gold standard).

RESULTS

Sensitivity was improved after the PACS introduction. When both certain and uncertain findings were included, this improvement was statistically significant. There were no other statistically significant changes.

CONCLUSION

The result is consistent with prospective studies concluding that diagnostic accuracy is at least not reduced after PACS introduction. The sensitivity may even be improved.

Comparison of flat-panel digital to conventional film-screen radiography in detection of experimentally created lesions of the equine third metacarpal bone

Radiographic diagnosis of equine bone disease using digital radiography is prevalent in veterinary practice. However, the diagnostic quality of digital vs. conventional radiography has not been compared systematically. We hypothesized that digital radiography would be superior to film-screen radiography for detection of subtle lesions of the equine third metacarpal bone. Twenty-four third metacarpal bones were collected from horses euthanized for reasons other than orthopedic disease. Bones were dissected free of soft tissue and computed tomography was performed to ensure that no osseous abnormalities were present. Subtle osseous lesions were produced in the dorsal cortex of the third metacarpal bones, and the bones were radiographed in a soft tissue phantom using indirect digital and conventional radiography at standard exposures. Digital radiographs were printed onto film. Three Diplomates of the American College of Veterinary Radiology evaluated the radiographs for the presence or absence of a lesion. Receiver operator characteristic curves were constructed, and the area under these curves were compared to assess the ability of the digital and film-screen radiographic systems to detect lesions. The area under the ROC curves for film-screen and digital radiography were 0.87 and 0.90, respectively (P = 0.59). We concluded that the digital radiographic system was comparable to the film-screen system for detection of subtle lesions of the equine third metacarpal bone.

MRI of meniscal lesions: soft-copy (PACS) and hard-copy evaluation versus reviewer experience

OBJECTIVE

The purpose of our study was to compare diagnostic performance, reviewer confidence, and time requirements in the MRI diagnosis of meniscal tears for three types of reviewers and two types of image documentations (PACS vs hard copies).

MATERIALS AND METHODS

An experienced musculoskeletal radiologist (reviewer 1), a fellow in musculoskeletal radiology (reviewer 2), and a junior staff member in orthopedic surgery (reviewer 3) evaluated MR images displayed on PACS monitors and hard copies independently and in a blinded fashion with regard to the presence or absence of meniscal tears. Seventy-one patients (mean age, 45.4 years; range, 16-80 years) were consecutively included if they had undergone both MRI of the knee and arthroscopy within 4 months. Arthroscopy was the standard of reference. Evaluation time and the reviewer's confidence in his or her diagnosis (Visual Analogue Scale, possible values of 0-100) were determined.

RESULTS

Accuracies, sensitivities, and specificities in diagnosing meniscal tears were 80-87%, 63-85%, and 87-93% for soft copies and 82-85%, 64-76%, and 87-94.0%, respectively, for hard copies. Intrareviewer differences between PACS and hard copies were not significant for any of the three reviewers (McNemar tests). Reviewer 3 was less sensitive but more specific in the diagnosis of meniscal tears than reviewers 1 and 2. This difference was significant for both the PACS and hard copies. The reviewers' confidence in their diagnoses and evaluation times were not significantly different for PACS and hard copies (analysis of variance with Bonferroni post hoc analysis).

CONCLUSION

Differences in the diagnostic performance of suspected meniscal tears depend on reviewer experience rather than on the type of documentation.

Clinical outcomes associated with telemedicine/telehealth

This paper is a comprehensive review and synthesis of the literature concerning clinical outcomes associated with various telemedicine applications. It starts out with a brief description of the findings reported by similar literature reviews already published. Subsequently, it proposes a conceptual model for assessing clinical outcomes based on Donabedian's formulation of the Medical Care Process. Accordingly, research findings are reported in terms of the relevant components of the medical care process, namely, diagnosis, clinical management, and clinical outcomes. Specific findings are organized according to the designated clinical and diagnostic application. This is followed by a general report of studies dealing with patient satisfaction.

Pulmonary nodule detection and visual search: P45 and P104 monochrome versus color monitor displays

RATIONALE AND OBJECTIVES

The faceplate of a cathode-ray tube (CRT) display monitor is covered on the vacuum side with a phosphor screen. The different phosphors that can be used for this screen have distinctly different physical properties that can affect the noise properties of the display. Differences in noise affect the signal-to-noise ratio and, hence, may affect diagnostic performance. This study evaluated observer performance and visual search parameters in the detection of pulmonary nodules, comparing two monochrome CRT monitors with different phosphors (P45 and P104) and a color CRT monitor.

MATERIALS AND METHODS

The receiver operating characteristic paradigm was used to evaluate observer performance with a series of radiographic chest images containing solitary pulmonary nodules. Eye position was recorded as the observers searched the images on each type of monitor.

RESULTS

Observer performance, as indicated by the area under the receiver operating characteristic curve and compared by means of an analysis of variance test, was best for the P45 monitor, next best for the P104 monitor, and worst for the color monitor. All differences were statistically significant. Eye-position parameters were also affected by monitor type. The time required to fixate the lesion and overall search times were longest with the color monitor.

CONCLUSION

The type of phosphor used in the CRT monitor faceplate can affect diagnostic performance and visual search parameters. Care should be taken in the selection of monitors for use in clinical radiology.

Computed radiography

CR is a useful tool for the equine veterinarian and has many advantages. Its only major disadvantage is the initial cost, in dollars and time, for setup in one's practice. CR is already in use at several universities and private practices in the United States and around the world. In the future, as is the case with any computer-based technology, this modality should become more affordable and readily available to smaller practices. The potential of CR in veterinary medicine combined with saturation of the human market is driving the development of specialized software and algorithms for veterinary medicine.