Practice variation in neuroimaging to evaluate dizziness in the ED

Abstract

Background The appropriate role of neuroimaging to evaluate emergency department (ED) patients with dizziness is not established by guidelines or evidence. Methods We identified all adults with a triage complaint of dizziness who were evaluated at 20 EDs of a large Northern California integrated health care program in 2008. Using comprehensive medical records, we captured all head computed tomographies (CTs) or brain magnetic resonance images (MRIs) completed at presentation or within 2 days and all stroke diagnoses within 1 week. We assessed variation in neuroimaging use by site using a random-effects logistic model to account for differences in patient- (demographic and vascular risk factors) and site-level factors (volume, % patients with dizziness, and % patients with dizziness admitted) and linear regression to assess the relationship between neuroimaging rates and stroke diagnosis rates by site. Results Of 378 992 patients seen in 2008, 20 795 (5.5%) had at least one ED visit for dizziness. Overall, 5585 patients (26.9%) had a head CT and 652 (3.1%) had a brain MRI. Between 21.8% and 32.8% of ED patients with dizziness at each site had a head CT (P < .001). For brain MRI, the range was 0.8% to 6.2%—a nearly 8-fold variation (P < .001) that persisted after adjustment for patient- and site-level factors. Higher neuroimaging rates did not translate into higher stroke diagnoses rates, with 0.7% to 2.5% of patients with dizziness diagnosed with stroke by site. Conclusion The use of neuroimaging for ED patients with dizziness varies substantially without an associated improvement in stroke diagnosis, which is identified only rarely.

The Usefulness of Magnetic Resonance Imaging for Acute Isolated Vertigo Patients in the Emergency Department

“…However, the use of MRI has many limitations in terms of cost and equipment. In addition, there have been some reports that use of MRI does not increase the detection rate of acute infarction, which is one of the most common reasons for the central origin of acute vertigo [8,9] .…”

“…The use of neuroimaging studies to diagnose vertigo in the ED has increased [7,8] . Recently, the importance of MRI for acute vertigo in the ED has been reported; a small stroke within the posterior fossa can present as acute severe dizziness, mimicking vestibular neuritis [2,16] .…”

“…Despite the relative lack of research on the comparative effectiveness of the application and yield of these neuroimaging methods in the ED, many such imaging studies are performed worldwide to evaluate patients with dizziness in the ED. However, these neuroimaging studies do not improve the diagnosis of stroke, which is one of the most critical causes of acute isolated vertigo [8,9] .…”

Yield of CT Angiography and Contrast-Enhanced MR Imaging in Patients with Dizziness

“…Despite the significant variability in the type of imaging studies performed in the evaluation of patients with dizziness-some of which is undoubtedly due to local biases-an improvement in patient outcomes has yet to be established for any of the various imaging protocols. 30 Some authors have attempted to emphasize physical examination in lieu of reliance on imaging. 31 Reliance on imaging in the emergency department may also be driven by a fear of missing a potentially treatable vertebral artery dissection with associated medullary infarction.…”

Using Diastolic Blood Pressure to Diagnose Acute Stroke in Isolated Acute Vestibular Syndrome

“…Despite extensive emergency department (ED) workups, the diagnostic accuracy of a central cause of AVS is low (approximately 35% of strokes are missed). 3,4 If patients who present with AVS have focal neurologic signs, stroke will be diagnosed relatively easily. However, only around 20% do present with focal signs, and the remainder have isolated AVS.…”