Amee A. Patel, MD, University of Maryland School of Medicine; Daniel Kunaprayoon, MD; Naomi J. Saenz, MD; Khan M. Siddiqui, MD; Nabile M. Safdar, MD; Ryan Moffitt; Eliot L. Siegel, MD, FSIIM; Rebecca Wright, MD

Radiologists not only benefit physiologically from increased daily activity using a treadmill-based workstation to interpret images, but also maintain their interpretation accuracy

Introduction:

The “Walkstation” is a treadmill-based workstation that has been introduced into our radiology department for routine image review and interpretation. It utilizes a three monitor configuration, as well as a treadmill that can be set at speeds from 0.3 to 2.0 miles per hour. The treadmill is especially designed for minimal noise output in order to minimize distraction from noise and the potential negative impact on speech recognition. This treadmill-based workstation offers radiologists the opportunity to perform their work while enjoying the well-documented benefits of increased daily activity, which include improved physical and mental health. Previous studies have suggested an increase in energy expenditure from 72 kcal/h, while sitting, to 191 kcal/h, when walking at a rate of 1.1 mph. There is also an increase in metabolic rate by as much as 154%. The purpose of this study is to determine the impact of the use of the Walkstation on image interpretation.

A total of 20 de-identified PA chest radiographs were selected from our imaging archives. The cases included ten normal and ten abnormal cases that demonstrated a subtle lung nodule or mass. Eight readers, including 4 attendings and 4 residents, reviewed conventional chest radiographs on a computer monitor in 3 randomized test positions, which included sitting, standing, and walking at 1 mph. Each session consisted of 5 practice cases followed by 20 chest radiographs in a randomized order with only 5 seconds allotted to each case. The readers were asked whether a nodule was present in each case, asked to identify its location in the upper, mid, or lower lung, and asked to identify the side of pathology if present. Each reader had approximately 24 hours between each of his/her three sessions.

The average sensitivity for the detection of lung nodules was 80% for walking, 76% for standing, and 71% when sitting. The specificity however, was 56% for walking, 69% for standing, and 77% for sitting. There were no significant differences in sensitivity, specificity, or accuracy (p=0.369, ANOVA). There was no evidence of a memory effect between the first, second, and third sessions (p=.37)

The routine use of a treadmill-based workstation for a portion of the day may provide substantial health benefits without a deleterious impact on image interpretation. Initial studies at our institution have not been able to document any decrease in accuracy in the interpretation of conventional chest radiographs in the detection of lung nodules when using the Walkstation and, in addition, multiple previous studies (not in the imaging literature) have suggested a positive impact of low level exercise on memory and concentration. Initial studies of a treadmill-based workstation in other domains outside of medical imaging have been promising, and subjective impressions of our workstation have been positive as well. The sedentary workday of most radiologists could be ameliorated with an hour or more per day on this unique workstation. One limitation of the study was the fact that the radiologists were on the treadmill a relatively short period of time (a few minutes) prior to the start of the image interpretation task. We did not monitor their change in heart rate or blood pressure to determine the change in comparison to baseline. We plan to perform additional testing that includes cardiovascular and metabolic monitoring of radiologists at our facility, as well as galvanic skin response and, if practical, blood flow studies, to further evaluate the impact of the Walkstation from a physiologic as well as cognitive perspective.

The use of the Walkstation was not associated with a significant decrease in accuracy despite the relative lack of experience of the radiologists on the treadmill-based workstation. Although our study was not able to test the impact that low level exercise had on memory and concentration, there are a number of papers that suggest that exercise is associated with improvement in memory and concentration. Limitations of the study included the lack of a longer warm-up period on the treadmill and the difference between the test conditions with a high level of suspicion of disease in comparison to routine image interpretation. Initial results suggest the Walkstation may play a role in providing an opportunity for low level exercise without significantly decreasing productivity or accuracy. Additional evaluation should be performed of this promising addition to the reading room.

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