Rationale and Objectives
To examine the effect of changes in utilization and advances in cross-sectional imaging on radiologists’ workload.
Materials and Methods
All computed tomography (CT) and magnetic resonance imaging (MRI) examinations performed at a single institution between 1999 and 2010 were identified and associated with the total number of images for each examination. Annual trends in institutional numbers of interpreted examinations and images were translated to changes in daily workload for the individual radiologist by normalizing to the number of dedicated daily CT and MRI work assignments, assuming a 255-day/8-hour work day schedule. Temporal changes in institutional and individual workload were assessed by Sen’s slope analysis ( Q = median slope) and Mann–Kendall test ( Z = Z statistic).
Results
From 1999 to 2010, a total of 1,517,149 cross-sectional imaging studies (CT = 994,471; MRI = 522,678) comprising 539,210,581 images (CT = 339,830,947; MRI = 199,379,634) were evaluated at our institution. Total annual cross-sectional studies steadily increased from 84,409 in 1999 to 147,336 in 2010, representing a twofold increase in workload ( Q = 6465/year, Z = 4.2, P < .0001). Concomitantly, the number of annual departmental cross-sectional images interpreted increased from 9,294,140 in 1990 to 94,271,551 in 2010, representing a 10-fold increase ( Q = 8707876/year, Z = 4.5, P < .0001). Adjusting for staffing changes, the number of images requiring interpretation per minute of every workday per staff radiologist increased from 2.9 in 1999 to 16.1 in 2010 ( Q = 1.7/year, Z = 4.3, P < .0001).
Conclusions
Imaging volumes have grown at a disproportionate rate to imaging utilization increases at our institution. The average radiologist interpreting CT or MRI examinations must now interpret one image every 3–4 seconds in an 8-hour workday to meet workload demands.
Over the past decade, advanced cross-sectional imaging utilization has been rapidly increasing . Fueled by technical innovations that have improved the anatomic resolution, sensitivity, and specificity of computed tomography (CT) and magnetic resonance imaging (MRI) modalities, medical practice has evolved to heavily rely on these imaging techniques over older, conventional radiographic imaging modalities . Indeed, many clinical practice guidelines, particularly in the emergent setting, have supplanted conventional radiography with CT and MRI examinations as the key elements in their clinical decision-making algorithm . Much of this evolution has been driven by evidence-based medicine of the superiority of cross-sectional imaging over conventional radiography in the accurate detection of disease . Advances in multidetector CT, dual-source CT, gradient-based MR pulse sequences, and novel pulse sequences have also greatly diminished the acquisition time of these studies, permitting a higher-throughput model of health care delivery .
As imaging reimbursements decline, health care providers are being forced to compensate by increasing their productivity . Although the information technology infrastructure of radiology has evolved to meet the demands of higher imaging volumes vis-a-vis improved computational power, storage capacity, and workflow efficiency in the picture archiving and communication system (PACS) environment, the amount of information (images) generated per examination has also substantially increased as a result of the technological advances noted previously . In turn, the modern radiologist must now interpret many times more examination images when compared to similar examinations performed 10–20 years ago. Although these advances in sensitivity and specificity are thought to translate to improved patient care, these increasing imaging volumes are placing an ever-increasing burden on the practicing radiologist . As the workload continues to increase, there is concern that the quality of the health care delivered by the radiologist will decline in the form of increased detection errors as a result of increased fatigue and stress . As errors in the interpretation of radiologic images can be associated with catastrophic clinical outcomes, such concerns are tantamount to patient safety.
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Materials and methods
Study Design
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Study Grouping
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Departmental Staffing/Practice Patterns
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Departmental Imaging and Data Storage Policies
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Outcomes
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Statistical Analysis
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Results
Trends in Number of Examinations Over Time
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Table 1
Trends Over Time in Radiologist’s Workloads
Type Change Per Year Median Change (95% CI) ∗ P Value Total examinations interpreted/year CT 4499 (3218 to 5317) <.0001 MRI 2215 (1885 to 2408) <.0001 CT + MRI 6464 (5069 to 7885) <.0001 Total images interpreted/year CT 6,112,616 (8,160,952 to 3,870,723) <.0001 MRI 2,401,985 (2,868,584 to 2,051,647) <.0001 CT + MRI 8,707,876 (8,160,952 to 10,993,169) <.0001 Mean number of images/study CT 59 (39 to 78) <.0001 MRI 38 (29 to 45) <.0001 CT + MRI 54 (43 to 63) <.0001 Number of worklines † CT 1.2 (0.9 to 1.3) <.001 MRI 0.3 (−0.1 to 0.6) .08 Examinations interpreted/year/workline † CT −86 (−170 to 12) .04 MRI 76 (21 to 135) .01 CT + MRI 18 (−75 to 70) .32 Images interpreted/year/workline † CT 214,873 (164,376 to 249,607) <.0001 MRI 107,145 (74,876 to 134,855) <.0001 CT + MRI 179,071 (152,309 to 199,931) <.0001 Images interpreted/minute CT 1.8 (1.34 to 2.04) <.0001 MRI 0.9 (0.61 to 1.01) <.0001 CT + MRI 1.5 (1.24 to 1.63) <.0001
CI, confidence interval; CT, computed tomography; MRI, magnetic resonance imaging.
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Trends in Number of Images per Examination
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Imaging Trends by Examination Type and Subspecialty
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Trends in Radiologist Workload Over Time
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Discussion
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