How many screens does a CT workstation need?

Evolution of the digital revolution: a radiologist perspective

The transformation from film-based to filmless operation has become more and more challenging, as imaging studies expand in size and complexity. To adapt to these changes, radiologists must proactively develop new workflow strategies to compensate for increasing work demands and the existing workforce shortage. This article addresses the evolutionary changes underway in the radiology interpretation process and reviews changes that have occurred in the past decade. These include a number of developments in soft-copy interpretation, which is migrating from a relatively static process, duplicating film-based interpretation, to a dynamic process, using multi-planar reconstructions, volumetric navigation, and electronic decision support tools. The result is optimization of the human-computer interface with improved productivity, diagnostic confidence, and interpretation accuracy.

Accuracy of interpretation of CT scans: comparing PACS monitor displays and hard-copy images

OBJECTIVE

The purpose of this study was to determine the relative diagnostic accuracy of radiologists in the interpretation of CT scans using a computer workstation in comparison with using film.

MATERIALS AND METHODS

Four board-certified radiologists with extensive soft-copy experience interpreted 117 CT scans in four anatomic regions using films displayed on an alternator and images displayed on a four-monitor workstation. The radiologists were asked to interpret the scans in their usual fashion and were aware that both the time required to review the study and the accuracy of the reports were being assessed. The radiologists' diagnostic impressions were compared with those of a consensus panel and scored for accuracy.

RESULTS

Soft-copy interpretation using computer workstations was found to produce statistically significant improvement in combined measurements of sensitivity, specificity, and overall accuracy for chest, brain, and chest-abdominal CT scans compared with film interpretation.

CONCLUSION

PACS (picture archiving and communication system) offers radiologists the potential for improved accuracy in CT interpretation compared with traditional film-based interpretation.

Radiologists' productivity in the interpretation of CT scans: a comparison of PACS with conventional film

OBJECTIVE

We compared radiologists' times in the interpretation of CT using hardcopy films with the interpretation using a soft-copy picture archiving and communication system (PACS) computer workstation.

MATERIALS AND METHODS

One hundred CT examinations were selected at random and reviewed by four board-certified radiologists experienced in soft-copy interpretation. We performed time-motion analysis to determine the total time required to display, interpret, and dictate the individual findings of CT using conventional hard-copy interpretation on a viewbox and soft-copy interpretation, using a four-monitor high-resolution (2048 x 1536 pixel) workstation.

RESULTS

Time-motion analysis showed a reduction of 16.2% in the overall time required for soft-copy interpretation of CT compared with that of film. Time savings with soft-copy interpretation were observed for all four participating radiologists. The benefit of soft-copy interpretation was increased for examinations in which there were comparison studies.

CONCLUSION

We found that soft-copy interpretation of CT using a PACS workstation requires less time than interpretation using conventional film hung on a viewbox. The transition to filmless imaging has the potential to improve radiologists' productivity and report-turnaround time.

A picture archiving and communications system featuring multiple monitors using Windows98

We present an effective approach to manage, review, and distribute Digital Imaging and Communications in Medicine (DICOM) images with multiple monitors using Windows98 (Microsoft Corp, Redmond, WA) that can be implemented in an office-based setting. Computed tomography (CT), magnetic resonance imaging (MRI), and angiographic DICOM images were collected, compressed, and stored using Medweb (Medweb, Inc, San Francisco, CA) software. The Medweb server used the Linux/UNIX operating system on a Pentium 333-MHz processor with 128 MB of RAM. Short-term storage capacity was about 2 weeks with routine usage of an 11-GB hard drive. Images were presented for reading on a dual-monitor Windows98 Pentium display station with 160 MB of RAM using a Medweb/Netscape (Netscape Communications Corp, Mountain View, CA) viewer. There was no significant discrepancy in diagnosis between electronic and conventional film images. Mean reading time for 32 cases was 118 seconds. The Medweb JAVA plug-in viewer loaded the first image within 30 seconds of selecting the case for review. Full uncompressed 16-bit images allowed different window settings to better assess for pathology. Multiple monitors allowed viewing various hanging protocols. Cine viewing was also possible. Key diagnostic images were electronically transmitted to referring physicians. On-call radiologists were able to access images through the Internet. By combining Medweb, DICOM, and web-browser software using desktop personal computers (PCs), an easily accessible picture archiving and communications system (PACS) is available to radiologists and referring physicians. Multiple monitors are easily configured and managed using Windows98. This system can sustain changes and can be extended to provide variable functions using inexpensive PCs.

Differences in time to interpretation for evaluation of bone radiographs with monitor and film viewing

RATIONALE AND OBJECTIVES

The authors evaluated how observers search hard-copy versus soft-copy images to determine why viewing times are longer for images displayed on a monitor.

METHODS

Twenty-seven nonconsecutive bone-trauma computed radiographs were collected from the routine emergency practice. Eye positions of three bone radiologists and three orthopedic surgeons were recorded as they searched images on a view box and digital images at a workstation.

RESULTS

Overall viewing time was longer for images displayed on a monitor. Time to first fixate a lesion and true-negative dwell times were significantly longer with the monitor than with the film. Absolute numbers of clusters and dwell times were greater for diagnostic image areas on the monitor than on the film. Twenty percent of the clusters for images viewed on the monitor were on the image-processing menu.

CONCLUSION

The amount and type of information that is processed during search is different when images are viewed on a monitor rather than on film.

Processes involved in reading imaging studies: workflow analysis and implications for workstation development

Software development for imaging workstations has lagged behind hardware availability. To guide development and to analyze work flow involved in interpretation of cross-sectional imaging studies, we assessed the cognitive and physical processes. We observed the performance and interpretation of body computed tomography (CT) scans and recorded the events that occurred during this process. We studied work flow using a bottleneck analysis. Twenty-four of a total of 54 cases (44%) involved comparing the images with those of prior scans. Forty-seven of 54 scans (87%) were viewed using windows other than soft tissue, or compared with precontrast scans. In 46 cases (85%), the interpretation stopped to return to a previous level for review. Measurement of lesions was performed in 24 of 54 (44%) cases, and in 15 (63%) of these cases, measurements were taken of lesions on old studies for comparison. Interpretation was interrupted in 14 of 54 cases (26%) by referring clinicians desiring consultation. The work flow analysis showed film folder retrieval by the film room to be the bottleneck for interpretation by film. For picture archiving and communication system (PACS) reading, the CT examination itself proved to be the bottleneck. We conclude that workstations for CT interpretation should facilitate movement within scans, comparison with prior examinations, and measuring lesions on these scans. Workstation design should consider means of optimizing time currently not used between interpretation sessions, minimizing interruptions and providing more automated functions currently requiring physician interaction.

Computed tomography interpretations with a low-cost workstation: a timing study

An ergonomically simple prototype workstation with two 900 x 1,100-pixel monitors capable of displaying eight full-resolution computed tomography (CT) images in 0.2 seconds, was compared with film for interpretation of computed tomographic images of the chest and abdomen. The hardware platform for this workstation cost less than $11,500 in 1993. A repeated-measures experiment was used to generate average interpretation times of 6.17 minutes for the workstation and 6.03 minutes for the film, including loading and unloading films, with three of the four subjects averaging about a minute longer for each workstation interpretation. All dictated reports were of clinically acceptable accuracy. All radiologists stated that workstations based on this design would be an acceptable clinical tool. However, observation suggested human working-memory strain among infrequent CT readers that could indicate the need for additional training. These data suggest that low-cost workstations can have practical application in interpretation of digital medical images such as CT, with the possibility of small increases in interpretation time.