Are patients with acute ischemic stroke required to undergo both CT and MRI exams?

USA: A recent study in JAMA Network Open has suggested that it may not be necessary for patients with acute ischemic stroke to undergo both computed tomography (CT) and magnetic resonance imaging (MRI) exams. 

The study showed that in patients hospitalized with acute ischemic stroke, a diagnostic imaging strategy of initial CT alone was noninferior to initial CT plus additional MRI. The noninferiority was seen with regards to clinical outcomes at discharge and at 1 year. The researchers however suggested that further research is required to determine which patients hospitalized with acute ischemic stroke benefit from MRI.

In stroke patients, the use of MRI has increased from 28% to 66% between 1999 and 2008, but whether this adds value to stroke evaluation remains unclear. If MRI truly isn't necessary for stroke evaluation, eliminating it could lead to a reduction in unnecessary imaging. Considering this, Heitor Cabral Frade, Department of Neurology, the University of Texas Medical Branch at Galveston, and colleagues aimed to assess whether clinical outcomes of patients with acute ischemic stroke with initial CT alone were noninferior to those with additional MRI. 

For this purpose, the researchers conducted a retrospective observational propensity score–matched cohort study of clinical outcomes at discharge and 1 year for patients hospitalized with acute ischemic stroke at an academic medical center between January 2015 and December 2017. Data were collected from an electronic medical record system performed from May 2020 through January 2022. 

The basis for noninferiority margins was the designs of previous randomized clinical trials of ischemic stroke treatments. Participants were adults hospitalized with acute ischemic stroke with admission diagnosis based on CT. 

Exclusion criteria were primarily missing data. All 123 cases with additional MRI were propensity-score matched to 123 controls without, from 508 eligible patients.

Death or dependence at hospital discharge (modified Rankin Scale score of 3-6) and stroke or death occurring in survivors within 1 year after discharge was the primary outcome. 

The researchers conclude, "results of this study suggest that further research is needed to determine which patients hospitalized with acute ischemic stroke benefit from MRI in addition to initial CT."

Reference:

Cabral Frade H, Wilson SE, Beckwith A, Powers WJ. Comparison of Outcomes of Ischemic Stroke Initially Imaged With Cranial Computed Tomography Alone vs Computed Tomography Plus Magnetic Resonance Imaging. JAMA Netw Open. 2022;5(7):e2219416. doi:10.1001/jamanetworkopen.2022.19416