Background: There are limited data on the frequency of repeat non-invasive imaging performed in the evaluation of stroke patients and its utility in patient care.
Hypothesis: Stroke patients frequently undergo repeat intracranial arterial imaging with limited change in clinical management.
Methods: All stroke patients admitted to a comprehensive stroke center from January 1, 2012 through December 31, 2014 were identified as part of a prospective radiology database if they underwent contrast-enhanced MR angiography (CE-MRA) of the head and subsequent CT angiography (CTA) of the head within 7 days. Two vascular neurologists reviewed medical records to confirm the diagnosis of stroke and subtype, determine the indications of the two studies, evaluate if any neurologic change occurred prompting the subsequent CTA, new findings seen on CTA and identification of any change in clinical management based on the CTA results.
Results: Of 1355 stroke patients who underwent CE-MRA of the head during the study period, 195 (14%) patients underwent subsequent CTA within 7 days, including 33 patients who had non-diagnostic CE-MRA due to patient motion. Of the 162 (12%) patients with diagnostic CE-MRA who underwent subsequent CTA head (mean age 59 ± 15 years, 52% female, 61% ischemic stroke, 11% ICH, 28% SAH), 69 (43%) patients were considered to have an unnecessary CTA of the head. In multivariable analysis, factors associated with an unnecessary CTA head included no new neurological exam changes [OR 7.29; 95% CI 1.92 to 27.63] and same documented indication for CE-MRA and CTA [OR 6.47; 95% CI 3.04 to 13.78]. Changes in clinical management after CTA of the head were seen in 42% of patients who had a clinically indicated CTA versus 7% of patients with a CTA considered unnecessary (p<0.0001).
Conclusions: Approximately 1 in 8 stroke patients who underwent a diagnostic CE-MRA underwent a subsequent CTA of the head within 7 days and nearly half of these CTA studies were considered unnecessary. The utility of repeat cerebrovascular head imaging with CTA of the head after a diagnostic CE-MRA is low when there is no evidence of a change in neurological exam or when the same indication is documented for both studies.