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1.  Evaluating Eyegaze Targeting to Improve Mouse Pointing for Radiology Tasks 
Journal of Digital Imaging  2009;24(1):96-106.
In current radiologists’ workstations, a scroll mouse is typically used as the primary input device for navigating image slices and conducting operations on an image. Radiological analysis and diagnosis rely on careful observation and annotation of medical images. During analysis of 3D MRI and CT volumes, thousands of mouse clicks are performed everyday, which can cause wrist fatigue. This paper presents a dynamic control-to-display (C-D) gain mouse movement method, controlled by an eyegaze tracker as the target predictor. By adjusting the C-D gain according to the distance to the target, the mouse click targeting time is reduced. Our theoretical and experimental studies show that the mouse movement time to a known target can be reduced by up to 15%. We also present an experiment with 12 participants to evaluate the role of eyegaze targeting in the realistic situation of unknown target positions. These results indicate that using eyegaze to predict the target position, the dynamic C-D gain method can improve pointing performance by 8% and reduce the error rate over traditional mouse movement.
PMCID: PMC3046801  PMID: 19902299
User–computer interface; observer performance; radiology workstation; eye movements; image navigation; dynamic C-D; Fitts’ law
2.  Evaluating Interaction Techniques for Stack Mode Viewing 
Three interaction techniques were evaluated for scrolling stack mode displays of volumetric data. Two used a scroll-wheel mouse: one used only the wheel, while another used a “click and drag” technique for fast scrolling, leaving the wheel for fine adjustments. The third technique used a Shuttle Xpress jog wheel. In a within-subjects design, nine radiologists searched stacked images for simulated hyper-intense regions on brain, knee, and thigh MR studies. Dependent measures were speed, accuracy, navigation path, and user preference. The radiologists considered the task realistic. They had high inter-subject variability in completion times, far larger than the differences between techniques. Most radiologists (eight out of nine) preferred familiar mouse-based techniques. Most participants scanned the data in two passes, first locating anomalies, then scanning for omissions. Participants spent a mean 10.4 s/trial exploring anomalies, with only mild variation between participants. Their rates of forward navigation searching for anomalies varied much more. Interaction technique significantly affected forward navigation rate (scroll wheel 5.4 slices/s, click and drag 9.4, and jog wheel 6.9). It is not clear what constrained the slowest navigators. The fastest navigator used a unique strategy of moving quickly just beyond an anomaly, then backing up. Eight naïve students performed a similar protocol. Their times and variability were similar to the radiologists, but more (three out of eight) students preferred the jog wheel. It may be worthwhile to introduce techniques such as the jog wheel to radiologists during training, and several techniques might be provided on workstations, allowing individuals to choose their preferred method.
PMCID: PMC3043711  PMID: 18649069
Stack mode image navigation; user interaction devices; mouse scrolling interaction; jog-shuttle wheel
3.  Designing Better Radiology Workstations: Impact of Two User Interfaces on Interpretation Errors and User Satisfaction 
Journal of Digital Imaging  2005;18(2):109-115.
This paper presents our solution for supporting radiologists’ interpretation of digital images by automating image presentation during sequential interpretation steps. We extended current hanging protocols with support for “stages” which reflect the presentation of digital information required to complete a single step within a complex task. We demonstrated the benefits of staging in a user experiment with 20 lay subjects involved in a comparative visual search for targets, similar to a radiology task of identifying anatomical abnormalities. We designed a task and a set of stimuli that allowed us to simulate the interpretation workflow from a typical radiology scenario—reading a chest radiography exam when a prior study is also available. The simulation was enabled by abstracting both the radiologist’s task and the basic workstation navigation functionality. The staged interface was significantly faster than the traditional user interface, provided a 37% reduction in the interpretation errors, and improved user satisfaction.
PMCID: PMC3046708  PMID: 15827830
Radiology workstations; user interface; hanging protocols; interpretation errors; user satisfaction
4.  Design Requirements for Radiology Workstations 
Journal of Digital Imaging  2004;17(2):92-99.
This article stresses the importance of capturing feedback from representative users in the early stages of product development. We present our solution to producing quality requirement specifications for radiology workstations, specifications that remain valid over time because we successfully anticipated the industry trends and the user’s needs. We present the results from a user study performed in December 1999 in a radiology clinic equipped with state-of-the-art Picture Archiving and Communications Systems (PACS) and imaging scanners. The study involved eight radiologists who answered questions and provided comments on three complementary research topics. First, we asked our subjects to enumerate the advantages and the disadvantages for both softcopy and hardcopy reading. We identified the two major factors for productivity improvement through the use of PACS workstations: workflow re-engineering and process automation. Second, we collected radiologist feedback on the use of hanging protocols (HPs). The results indicated the high importance of automatic image organization through HPs, with the potential effect of reducing the interpretation time by 10–20%. Our subjects estimated that 10–15 HPs would cover about 85%–95% of the regular radiological examinations. Third, we investigated the impact of the display devices on the radiologist’s workflow. Our results indicated that the number and the properties of the monitors is a modality-specific requirement. The main results from this study on key functional requirements for softcopy interpretation only recently were incorporated in most of the current, successful PACS workstations.
PMCID: PMC3043976  PMID: 15085446
Radiology workstation; PACS; hanging protocols; ergonomics

Results 1-4 (4)