From the 2024 HVPA National Conference
Lauren Facer MD (University of Utah), Blair Winegar MD, Shilpa Raju MD, Micah Ownbey MD, Yoshimi Anzai, MD, MPH
Background:
Head and neck CTA (HN CTA) has been increasingly ordered through the Emergency Department (ED) for various clinical presentations, including dizziness and vertigo. HN CTA is utilized to diagnose serious medical conditions presenting with dizziness in the ED, including vertebral artery dissection and posterior circulation infarction. However, CTA H&N does not accurately diagnose posterior circulation infarction.
Purposes:
We have conducted 1) a retrospective review of HN CTA ordered from ED for a primary reason for dizziness/vertigo to determine the frequency of significant findings and 2) Educational Intervention targeted toward ED providers, including physicians, trainees, PA, and RN.
Materials and Methods:
The Radiology Information System was used to identify HN CTA performed between 1/1/2022 and 12/31/2022 from the ED. The primary indication was reviewed to identify those studies ordered for either dizziness or vertigo. The imaging reports were reviewed for any positive (significant) findings that led to additional diagnostic tests or changes in the management of patients. Educational Intervention, including the diagnostic algorithm and HINTS exam, was performed by a radiology resident as a part of a Quality Improvement project supported by the Neuroradiology faculty.
Results:
The total number of HN CTAs ordered from the ED was from 1965 studies conducted over 12-month periods. Among them, 291 studies were performed for a primary indication of dizziness and/or vertigo (15%). Imaging reports showed 32/291 patients (11%) had significant vascular findings or non-contrast CT findings concerning acute infarct. Among these 32 patients, 27 patients (9.2%) had vascular abnormalities such as luminal irregularity, severe stenosis, dissection, or occlusion, and 5 patients (2%) had head CT findings without CTA abnormality that necessitated brain MRI. All patients except one with HN CTA abnormality subsequently received brain MRI. Of these 31 patients with subsequent brain MRI, 11 patients (4%) had acute/subacute infarct, which included 2 patients with vascular dissection and 3 patients with complete vascular occlusion. The remainder of 20 out of 31 patients (65%) with HN CTA abnormality had no acute infarct on subsequent brain MRI. Of note, incidental aneurysm was found in 5 patients, pituitary mass in 2 patients, and thyroid nodule in 3 patients.
After the Educational session, there has been an increasing number of patients with dizziness who received non-contrast brain MR. We are evaluating the disposition of those patients who received brain MR versus CTA H&N.
Conclusion:
Dizziness is a common reason that HN CTA is performed for ED patients. However, the positivity rate for findings of significant vascular abnormality is 11%, and only 4% of patients have acute infarcts confirmed by brain MRI. The impact of physician education on diagnostic algorithms and the incorporation of the HINTS exam are currently ongoing.
Clinical implication:
The HINTS exam can divide dizziness/vertigo into central and peripheral causes. If the exam is positive, indicating peripheral vertigo/dizziness, cross-sectional imaging is low-yield. For central causes, brain MRI without contrast is more accurate than HN CTA for the detection of posterior circulation infarction.