Effects of Electronic Decision Support on High-Tech Diagnostic Imaging Orders and Patients

Electronic decision support for high-tech diagnostic imaging was associated with reduced volume and increased appropriateness, but had little impact on findings or patients.

Published Online: February 05, 2010
Leif I. Solberg, MD; Feifei Wei, PhD; John C. Butler, MD; Kevin J. Palattao, BA; Cally A. Vinz, RN; and Melissa A. Marshall, MBA

Objective: To evaluate the effects of providing appropriateness criteria through guideline-based electronic health record (EHR) decision support for high-tech diagnostic imaging (HTDI) procedures.

Study Design: Chart audits were performed on a random sample of adult primary care orders for 3 HTDI procedures (computed tomography [CT] and magnetic resonance imaging [MRI] of the head, and MRI of the lumbar spine) before and after implementation of an EHR decision support system.

Outcome Measures: Level of appropriateness, abnormal findings, and apparent effects on patient care.

Results: A total of 299 eligible audits were performed. Decision support was associated with a 20% to 36% drop in spine MRI and head CT orders, but head MRI order volume was unaffected. Combined results for the 3 procedures showed that a larger proportion of studies ordered after implementing decision support (89.2% vs 79.5%, P = .02) fit appropriateness criteria, and more postimplementation studies had A ratings (highest utility rating) (81.8% vs 70%, P = .04). However, there were no differences in the proportion of tests with positive findings (42/132 vs 28/120, P = .16 among procedures that met definite
criteria) or the proportion with a likely impact on patients (6.6% vs 10.8%, P = .07).

Conclusions: These data support the feasibility of using chart audits to assess the relationship between appropriateness criteria and HTDI orders. Although introduction of EHR clinical decision support for diagnostic imaging orders was associated with reduced volume and increased appropriateness of orders, there was little apparent impact on either findings or patients.

(Am J Manag Care. 2010;16(2):102-106)

Implementation of decision support in the electronic medical record system of a large medical group reduced the volume and increased the appropriateness of high-tech diagnostic imaging orders for head and spine scans, although the effects varied by procedure.

  • There was no increase in the proportion of scans with positive findings.
  • Few scans before or after implementation appeared likely to have affected patient outcomes.
  • Scans were as likely to affect the patient care process (usually by adding services) as to improve patient outcomes.

Many policymakers suggest that conversion to electronic health records (EHRs) will improve the quality and cost of medical care.1-3 Others argue that such benefits will require that EHRs include at least electronic decision support.4-7 However, there still is not much evidence about how much value electronic decision support adds. The systematic review of controlled trials of computerized decision support systems by Garg et al concluded that two-thirds of 97 trials showed some improvement in care processes, but only 7 of 52 showed improvement in patient outcomes.8

One area in which electronic decision support is likely to be helpful is in high-tech diagnostic imaging (HTDI) test orders. These very costly tests have been increasing at a rapid rate nationally over the past 15 years.9-16 Published studies suggest that this increase is occurring among tests ordered by both radiologists and nonradiologists and that it is associated with wide geographic variation in rates. As a result, there is increasing pressure to encourage adherence to appropriateness criteria, a situation for which electronic decision support seems well suited.

Rosenthal et al reported preliminary results from the implementation of an electronic decision support system for HTDI procedures at Massachusetts General Hospital, showing that it was acceptable to physicians and appeared to change ordering habits.17 However, this conclusion was based on changes in concordance with appropriateness criteria in the decision support system over time, with no data comparing such concordance before and after the system began. Moreover, there is little direct evidence on which to base appropriateness criteria. Thus, we know little about the effects on patient care processes or outcomes of applying these criteria. To better understand these issues, we studied the impact of implementing a decision support system for HTDI in the EHR of a large multispecialty medical group. The following questions were addressed:

1. Was there sufficient information in the medical chart to permit measurement of appropriateness criteria for HTDI test orders?

2. Did compliance with appropriateness criteria change?

3. Did positive findings or effects on patients change?


This study was conducted within a 600-physician multispecialty medical group in the Twin Cities region of Minnesota that serves an active patient population of 400,000 patients. Since 2004, its primary care clinics have used the Epic paperless EHR that includes computerized orders for all tests and incorporates either electronic or scanned reports of those test results.

In February 2007, the medical group rapidly implemented a decision support system within Epic for HTDI tests. The system used appropriateness criteria from the American College of Radiology that have ratings of A (high utility), B (intermediate utility), and C (low utility). Because the EHR ordering system required that a reason be entered for all orders, and because these criteria could not be expected to cover all circumstances, an “other” alternative also was available, which collected unstructured information for about 15% (8%-19%) of orders for the procedures we studied. Only completed orders were recorded in the EHR.

The system did not prevent orders, regardless of criteria fit. Physicians received little feedback on their order results (although system use identified the appropriateness of each order). There were no financial incentives or disincentives associated with ordering patterns.

To avoid the preparation or acclimatization periods before or after implementation for this study, as well as to avoid any seasonal effects on procedure orders, we selected 2-month windows (6 months before and 6 months after the decision support system was implemented). We studied 3 of the more commonly ordered HTDI procedures: computed tomography (CT) and magnetic resonance imaging (MRI) of the head, and MRI of the lumbar spine, because these procedures have relatively fewer and less complex ordering reasons than many others.17 Our study was limited to original orders (ie, not follow-up of a previous test) by a primary care clinician for adults (age 19 years and over) in our primary care clinics to further simplify and standardize the analysis.

The implemented system contained 72 criteria for CT of the head and 68 for MRI of the head, but only 27 for MRI of the lumbar spine. “A” ratings were associated with 65% of these criteria for CT of the head, whereas 85% of the criteria for the other 2 procedures had A ratings. If the apparent reason in the chart for ordering a test did not resemble any of the existing criteria, we recorded this test as lacking a criterion fit.

Fifty cases of each completed procedure were drawn randomly during the selected months before and after implementation of decision support. They were excluded if the order had actually come indirectly from a specialty consultant, or was a follow-up to an earlier test.

Audits were performed by 2 experienced nurse auditors using predetermined definitions. The 2 physicians in our group (LIS, JB) separately reviewed every case with positive findings to confirm the audit results and decide on the patient impact, followed by discussion between them until agreement was reached. During the training period for the audit, all auditors reviewed the same 15 cases, and we as a group discussed the issues raised by the cases to attain a common approach to data collection. Blinding either nurse or physician reviewers to the dates of the procedure was impossible, because they had to search the EHR for information needed.

Results of a test were called positive when an abnormality either seemed to explain the patient’s problem or required a medical decision. The effect on care was categorized as 1 of the following:

• Probable impact on patient health or function

• Impact on the care process (usually additional consultation or testing)

• Uncertain impact on patients or care

• No impact.

The analysis was limited to descriptive statistics, although there were enough cases with adequate information in the record so that there was sufficient power to detect large differences, especially when we combined the cases for all 3 procedures. To evaluate the association between the pre- and postimplementation periods for the fit with appropriateness criteria, compliance rating, tests with positive findings, test results within the normal range, and test results that led to changes in care decisions, we performed 2-sided Fisher exact tests.


During the 2-month study period in 2007 compared with 2006, the volume of completed test orders for these 3 procedures dropped for head CT and spine MRI by 36.5% and 20%, respectively. However, completed test orders for head MRI increased by 3.3%. A total of 38 cases were excluded, leaving 151 cases before and 148 cases after implementation. Sixty-two percent of the cases involved women and the mean age was 57.8 years, with no pre/post differences. Only 6% of the procedures were ordered by nurse practitioners.

Table 1 shows that the great majority of orders could be definitely rated by the criteria in both the pre–decision support and post–decision support periods, but only MRI of the head and spine showed an increase in definitely meeting appropriateness criteria after decision support was present. Only MRI of the head showed an increase in the proportion of orders rated as A in the postperiod. More than 90% of the head CTs were ordered for headache, trauma, or a neurologic deficit, and nearly all the spine MRIs were ordered for back pain or radiculopathy. Head MRIs also were ordered for headache or neurologic deficits, but many were ordered for evaluation of vertigo or other conditions.

Table 2 shows that neither of the head procedures had many positive findings, although MRI of the head did have an increase in positive findings in the postperiod, as well as an increase in the proportion clearly related to the specific indication for doing the test. Implementation of decision support did not change the very low frequency with which either type of head HTDI test impacted patients (2.5% of the time), but the greater impact of spine MRI increased even more in the postperiod (from 14% to 30%, P = .18). Except for MRI of the spine in the postperiod, all audits revealed a high proportion of incidental findings. Spine MRI orders that did not meet appropriateness criteria greatly increased the proportion of spine MRI results that had an impact on patients (from 7% to 62%) in the postperiod. Head HTDI orders that did not meet appropriateness criteria had no impact on patients in either the pre- or postperiod (data not shown in the table).

When we combined all 3 procedures, 10% more cases had a definite rating of appropriateness after implementation and 12% more cases with a definite rating of appropriateness had an A rating. No other differences were significant between the 2 time periods, and there was no evidence of an effect on positive findings or patients.


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