Original ArticleThe impact of installing an MR scanner in the emergency department for patients presenting with acute stroke-like symptoms
Introduction
MRI is widely established as invaluable in the assessment of patients with stroke-like symptoms (SLS), and recently has been increasingly used in the emergency department (ED) setting [1], [2]. The major diagnostic question for patients who present with new neurological signs or symptoms is whether these are related to acute cerebrovascular disease - ischemic or hemorrhagic - or whether the symptoms are due to non-cerebrovascular causes. MR diffusion-weighted imaging (DWI) is capable of demonstrating ischemic brain tissue changes within minutes of the insult, well in advance of detection by non-contrast CT [3], [4], [5], [6]. Prior studies have demonstrated MRI's superiority in the initial evaluation of patients with SLS and have called for utilization of MRI over CT in the acute setting [5], [6], [7], [8], [9], [10].
At our institution, an MR scanner was installed in the ED in early 2012 and became operational in April 2012. Prior to 2012, ED patients who needed MRI were assessed on inpatient scanners; however, this was performed on a limited basis prior to patient admission to the hospital. Since the installation of the scanner, we have observed an increased number of ED MRI exams ordered by ED physicians or stroke neurologists as a part of stroke work-up, at times preceding or completely replacing the non-contrast CT.
Our early experience with the in-ED scanner suggested that more patients were being “ruled out” for stroke through the rapid and early evaluation by the ED MR scanner and were thereby being discharged from the ED with a “non-stroke” diagnosis rather than being worked up as an inpatient. The stroke literature states that patients are at an increased risk of ischemic stroke in the time period immediately following TIA, with that risk being equal to 3.5% at 2 days, 5.2% at 7 days, 8.0% at 30 days, and 9.2% at 90 days after TIA [11], [12]. Given these data, a concern was raised that this early evaluation in the ED might lead to patients with cerebral ischemic symptoms being discharged from the ED while still at risk for subsequent stroke after a negative ED MRI.
We hypothesized that with the installation of the ED MR scanner, more admitted patients would get MRIs in the ED, and therefore the EDLOS would be longer (due to the added time of MRI examination), and HLOS would be shorter (due to a more timely “in-ED” patient evaluation and resulting appropriate early management). We also believed that the percentage of patients diagnosed with cerebrovascular ischemia admitted to the stroke service would be higher (because ED MRIs would screen out non-vascular pathologies before admission). We hoped that the rates of re-presentation to the ED and admission following a negative stroke work-up in the ED would be negligible.
Section snippets
Methods
In compliance with the Health Insurance Portability and Accountability Act (HIPAA), this study protocol was reviewed and approved by the Internal Review Board (IRB). Informed consent was waived due to the retrospective nature of the study.
Summary statistics
During the time interval from 7/1/2011–12/31/2011 (prior to scanner installation), 31,032 patients were evaluated in the ED and 362 patients (mean age: 52.9 years; age range: 19–94; male: 156) presented with SLS (2011 cohort). During the time interval from 7/1/2012–12/31/2012 (after scanner installation), 33,299 patients were evaluated in the ED and 448 patients (mean age: 50.9 years; age range: 7–95; male: 174) presented with SLS (2012 cohort). In the 2011 cohort, 196 (54.1%) of these patients
Discussion
Since installation of the MR scanner in the ED at our institution, a greater number of patients who are admitted with SLS underwent MRI examination in the ED setting (38.6% vs. 18.4%, p < 0.001). However, the overall proportion of the patients who got MR imaging as a part of stroke work-up did not change and remained at approximately 81%. Compared to 2011, in 2012, we observed a significantly higher number of patients admitted with SLS who were ultimately diagnosed with ischemic stroke (52.3% vs.
Conclusions
After installation of the MR scanner in the ED, there was increased utilization of the ED MR for patients presenting with SLS. ED MRs replaced those performed as an inpatient, so overall MRs/patient did not increase. More patients admitted on the stroke service actually had a stroke, therefore hospital length of stay for all patients did not decrease since patients without strokes are discharged more rapidly than those admitted with strokes. Patients discharged from the ED after a negative ED
Acknowledgments
None
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