Comparison of hard- and soft-copy digital chest images with different matrix sizes for managing coronary care unit patients

A Study on Establishing a Microstructure-Related Hardness Model with Precipitate Segmentation Using Deep Learning Method

This paper established a microstructure-related hardness model of a polycrystalline Ni-based superalloy GH4720Li, and the sizes and area fractions of γ' precipitates were extracted from scanning electron microscope (SEM) images using a deep learning method. The common method used to obtain morphological parameters of γ' precipitates is the thresholding method. However, this method is not suitable for distinguishing different generations of γ' precipitates with similar gray values in SEM images, which needs many manual interventions. In this paper, we employ SEM with ATLAS (AuTomated Large Area Scanning) module to automatically and quickly detect a much wider range of microstructures. A deep learning method of U-Net is firstly applied to automatically and accurately segment different generations of γ' precipitates and extract their parameters from the large-area SEM images. Then the obtained sizes and area fractions of γ' precipitates are used to study the precipitate stability and microstructure-related hardness of GH4720Li alloy at long-term service temperatures. The experimental results show that primary and secondary γ' precipitates show good stability under long-term service temperatures. Tertiary γ' precipitates coarsen selectively, and their coarsening behavior can be predicted by the Lifshitz-Slyozov encounter modified (LSEM) model. The hardness decreases as a result of γ' coarsening. A microstructure-related hardness model for correlating the hardness of the γ'/γ coherent structures and the microstructure is established, which can effectively predict the hardness of the alloy with different microstructures.

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.

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 paper print and soft copy reading in plain paediatric radiographs

With the introduction of a Picture Archiving and Communication System, Computed (CR) and Digital Radiography (DR), reading digital images takes place from a computer screen. Laser paper print rather than laser film would be a significantly more cost-effective option for hard copy production, but would need to demonstrate acceptable diagnostic quality compared to the reference standard of screen reading. A comparative study of 51 digital paediatric CR radiographs presented in laser paper print and soft copy format to determine the diagnostic value of the paper print when compared to the reference standard of screen reading. Chest radiography had a poor sensitivity of 66.1% while musculoskeletal and abdominal radiography had acceptable sensitivities of 90% and 99%, respectively. Specificity was excellent for the different regions (98.6-99.5%). The paper print format should not be used for diagnostic purposes in paediatric chest radiography, but may still be used for demonstration when accompanied by the radiology rapport obtained from soft copy reading. Further studies would be needed to investigate the use of paper prints in abdominal and musculoskeletal radiography owing to the low number of abdominal radiographs and lack of musculoskeletal case variety in our study.

Flat-panel display (LCD) versus high-resolution gray-scale display (CRT) for chest radiography: an observer preference study

OBJECTIVE

Our objective was to compare cathode ray tube (CRT) display with liquid crystal display (LCD) for soft-copy viewing of chest radiographs in a clinical setting.

MATERIALS AND METHODS

We displayed 80 posteroanterior digital chest radiographs side by side on a 5-megapixel CRT display and a 3-megapixel LCD. Gradation characteristics of both monitors were adjusted to DICOM display standards. Using a 4-point scale, seven radiologists ranked overall image quality and visibility of anatomic landmarks. Data analysis included Wilcoxon's rank sum test to assess the significance of preference for the different display modes and calculation of the percentage of images ranked equally by at least five of the seven radiologists.

RESULTS

Wilcoxon's rank sum test found significant preferences (p < 0.001) for the CRT display for visualization of structures in low-attenuation areas of the thorax and for the LCD for visualization of structures in high-attenuation areas of the thorax. Overall image quality was ranked equal by at least five radiologists in 70% of cases, whereas for the remaining images a significant preference was found for the CRT display.

CONCLUSION

We conclude that, under subdued ambient lighting conditions and without use of windowing, for most images the overall quality is equal with high-resolution CRT display and LCD. In images judged preferentially, we found a significant superiority for LCD for delineating mediastinal structures and for CRT display for delineating structures in the lung.

Soft-Copy Reading of Digital Chest Radiographs

OBJECTIVE

We sought to evaluate whether soft-copy reading of simulated pulmonary chest lesions is influenced by ambient light and automatic optimization of cathode ray tube (CRT) monitor luminance.

MATERIALS AND METHODS

Four types of simulated lesions (nodules, lines, micronodules, and patchy opacities) were superimposed over an anthropomorphic chest phantom. Lesion detection with soft-copy reading was assessed using a high-contrast grayscale 2K CRT monitor under the following conditions: (1) subdued lighting (<50 lux); (2) normal lighting conditions (450 lux) without, and (3) with a sensitivity modulation to automatically adjust the CRT luminance to the increased amount of ambient light. Reading data were analyzed according to receiver operating curve. Significance of differences was tested using an analysis of variance for repeated measures.

RESULTS

Ambient room light of 450 lux did not significantly influence the detection of nodules and patchy opacities. However, bright ambient light significantly decreased detection of micronodules (0.60 vs. 0.74) and lines (0.52 vs. 0.66) relative to subdued lighting conditions. Automatic luminance adjustment could compensate the effect of ambient light for the micronodules (0.77) but not for the lines (0.53).

CONCLUSION

Bright ambient light significantly decreases detection of small low-contrast structures. This may be partially but not completely compensated by an automatic luminance adaptation.

Radiology in the intensive care unit (Part I)

The increasing complexity of the intensive care patient combined with the recent advances in imaging technology has generated a new perspective on intensive care radiology. The purpose of this 2-part review article is to describe the contribution of radiology to the management of these critically ill patients. The first article will discuss the impact of picture archiving and communication system (PACS) on critical care management and utility of the portable chest radiograph in the detection and evaluation of pulmonary disease with correlation to computed tomography (CT). The second article describes in more detail the increasing role of CT in diagnosis and therapeutic procedures. In particular, the implementation of CT pulmonary angiography in the evaluation of pulmonary emboli and the introduction of the new multislice detector CT scanners that allow even the most dyspneic patient to be evaluated. Pleural complications in the intensive care unit and image-guided intervention will also be discussed.

A comparison of conventional film, CR hard copy and PACS soft copy images of the chest: analyses of ROC curves and inter-observer agreement

STUDY OBJECTIVE

The aim of this study was to determine whether the accuracy of diagnosis of a spectrum of chest pathology was affected by the imaging technique used, and to compare conventional film/screen, hard copy computed (phosphor plate) radiography (CR) and soft copy CR (PACS) images.

MATERIALS AND METHODS

For each of 44 patients who had a CT examination of the thorax, PA and lateral chest radiographs were produced using conventional film, hard copy CR and soft copy PACS images. Five radiologists independently scored all images for the presence of abnormalities. The data were analysed in two stages using the result of the CT scan as the reference standard diagnosis: firstly, to investigate differences in abnormality scores between image modalities and observers using ROC analysis; secondly, to investigate the agreement of the diagnoses with the reference standard by the analysis of kappa scores.

RESULTS

The ROC analyses and comparison of kappa scores showed no differences between image modalities (P=0.72, P=0.87), but highly significant differences between observers (P<0.001, P=0.003).

CONCLUSION

The detection of chest lesions did not vary between conventional film, CR hard copy and PACS soft copy images. For all three image types, there were statistically significant differences between observers.

Electronic imaging impact on image and report turnaround times

We prospectively compared image and report delivery times in our Urgent Care Center (UCC) during a film-based practice (1995) and after complete implementation of an electronic imaging practice in 1997. Before switching to a totally electronic and filmless practice, multiple time periods were consistently measured during a 1-week period in May 1995 and then again in a similar week in May 1997 after implementation of electronic imaging. All practice patterns were the same except for a film-based practice in 1995 versus a filmless practice in 1997. The following times were measured: (1) waiting room time, (2) technologist's time of examination, (3) time to quality control, (4) radiology interpretation times, (5) radiology image and report delivery time, (6) total radiology turn-around time, (7) time to room the patient back in the UCC, and (8) time until the ordering physician views the film. Waiting room time was longer in 1997 (average time, 26:47) versus 1995 (average time, 15:54). The technologist's examination completion time was approximately the same (1995 average time, 06:12; 1997 average time, 05:41). There was also a slight increase in the time of the technologist's electronic verification or quality control in 1997 (average time, 7:17) versus the film-based practice in 1995 (average time, 2:35). However, radiology interpretation times dramatically improved (average time, 49:38 in 1995 versus average time 13:50 in 1997). There was also a decrease in image delivery times to the clinicians in 1997 (median, 53 minutes) versus the film based practice of 1995 (1 hour and 40 minutes). Reports were available with the images immediately upon completion by the radiologist in 1997, compared with a median time of 27 minutes in 1995. Importantly, patients were roomed back into the UCC examination rooms faster after the radiologic procedure in 1997 (average time, 13:36) than they were in 1995 (29:38). Finally, the ordering physicians viewed the diagnostic images and reports in dramatically less time in 1997 (median, 26 minutes) versus 1995 (median, 1 hour and 5 minutes). In conclusion, a filmless electronic imaging practice within our UCC greatly improved radiology image and report delivery times, as well as improved clinical efficiency.

Impact of electronic imaging on clinician behavior in the urgent care setting

Although it is intuitively valuable that more expedient delivery of radiographic images and reports to clinicians would improve patient care, it is important to document these outcomes to validate further advances in these areas. We evaluated the care of 215 patients seen at a walk-in clinic to determine what benefit digital imaging is to the patient. Cohorts consisted of all patients for whom specified radiology examinations were ordered during a 7-day period. The first cohort was recruited when analog films were used. The second cohort received examinations performed with computed radiography (CR) acquisition and computer display, which had been in use for 2 years. Patients were categorized as to the type of study they received, as well as whether a staff radiologist was immediately available to read the study. Clinical behavior was characterized by outcome measures of time to final diagnosis, time to final treatment, and need for follow-up. Our analysis demonstrated a reduction in time to final diagnosis that was better appreciated during the times when a staff radiologist was not immediately available. It also suggested that greater time reductions were seen for patients who received extremity examinations than those who received chest, sinus, or rib films. These data suggest that digital imaging is a useful tool to improve clinical outcome of patients seen in the acute care setting.

Teleradiology: another revolution in radiology?

Teleradiology systems are rapidly being deployed by an increasing number of radiological services. Many articles have already been published on the technological developments of teleradiology but little attention has been given to its expected impact on the delivery of health care. This review article will therefore outline the historical and current technological developments of teleradiology and its potential future implementation into mainstream radiology.

A comparison between digital images viewed on a picture archiving and communication system diagnostic workstation and on a PC-based remote viewing system by emergency physicians

Picture Archiving and Communication Systems (PACS) make possible the viewing of radiographic images on computer workstations located where clinical care is delivered. By the nature of their work this feature is particularly useful for emergency physicians who view radiographic studies for information and use them to explain results to patients and their families. However, the high cost of PACS diagnostic workstations with fuller functionality places limits on the number of and therefore the accessibility to workstations in the emergency department. This study was undertaken to establish how well less expensive personal computer-based workstations would work to support these needs of emergency physicians. The study compared the outcome of observations by 5 emergency physicians on a series of radiographic studies containing subtle abnormalities displayed on both a PACS diagnostic workstation and on a PC-based workstation. The 73 digitized radiographic studies were randomly arranged on both types of workstation over four separate viewing sessions for each emergency physician. There was no statistical difference between a PACS diagnostic workstation and a PC-based workstation in this trial. The mean correct ratings were 59% on the PACS diagnostic workstations and 61% on the PC-based workstations. These findings also emphasize the need for prompt reporting by a radiologist.

Picture archiving communication system does not decrease the number of radiographs needed to evaluate the trauma patient

BACKGROUND

Picture Archiving Communication System (PACS) is a sophisticated software and hardware package that enables clinicians to retrieve, review, and digitally manipulate radiographs from computer workstations throughout the hospital. PACS was instituted at Brooke Army Medical Center in July 1993.

METHODS

Fifty consecutive trauma and 50 consecutive motor vehicle crash (MVC) trauma admissions to an urban trauma center were reviewed before PACS (January 1993) and 18 months after PACS was instituted (January 1995). Patients were compared by the number of radiographs needed during the initial evaluation by type and total. The trauma groups were subdivided by mechanism and also compared. Demographic and physiologic data were collected for each patient.

RESULTS

There are no differences in the demographic and physiologic data between groups. For the 50 consecutive trauma admissions, only two areas of statistical difference were found: more chest films were obtained in the MVC PACS group and more pelvis films were obtained in the gunshot wound pre-PACS group. For the 50 consecutive MVC trauma admissions, the PACS group had more chest and total radiographs per patient than the pre-PACS group. More computed tomographic scans of the neck were obtained in the PACS group.

CONCLUSION

PACS did not decrease the number of radiographs needed to adequately and fully evaluate the trauma patient.

Computed radiography in neonatal and pediatric intensive care units: a comparison of 2.5 K x 2 K soft-copy images vs digital hard-copy film

OBJECTIVE

The goal of the study was to determine whether soft-copy images on high-resolution monitors (2.5 K x 2 K) are suitable for primary interpretation of images from pediatric and neonatal intensive care units. The hypotheses were that hard and soft images yield similar diagnostic information, and that both residents and faculty radiologists can use monitors effectively. Previous reports have produced conflicting results; the need for larger sample sizes has been emphasized.

MATERIALS AND METHODS

One thousand one hundred and four images produced by computed radiography using the Kodak Ectascan Imagelink system were prospectively analyzed by two pediatric radiologists, one reading hard copy and the other soft copy of the same images. Bias was controlled by equal distribution of modalities between observers and by daily alternation of modality. Hard- and soft-copy observations of presence or absence of nine specific tubes and nine specific diagnostic findings were compared. Interobserver differences between pediatric radiologists and radiology residents were studied on additional images. The kappa statistic was used to evaluate the level of agreement for all observations.

RESULTS

There was excellent agreement between hard and soft copy interpretation for each tube and diagnostic finding (kappa values 0.93-1.0) and excellent interobserver agreement between two pediatric radiologists (kappa values 0.84-1.0). The level of agreement between radiology residents and pediatric radiologist was excellent for the most objective findings. All results were statistically significant (p < 0.001).

CONCLUSION

High resolution soft-copy images are suitable for primary interpretation in patients in pediatric and neonatal intensive care units.