Novel discovery suggests MRIs after cardiac arrest could predict patient outcomes

Patients who suffer brain damage after cardiac arrest could benefit from magnetic resonance (MR) imaging following their stabilization—a measure that has been shown to predict clinical outcomes through mapping brain activity, according to new research published in the American journal Radiology.

The sudden lack of blood flow during a cardiac arrest can result in oxygen deficiencies in the brain, author Robert D. Stevens, MD, and colleagues at Johns Hopkins wrote in their paper. Due to the nature of resuscitation and restoration of blood flow to the brain, patients are often left with disabling neurological and cognitive issues.

Stevens and his team analyzed 46 cardiac arrest patients for the study, all of whom were comatose following their heart events. Each patient underwent an MRI, which measured within- and between-network connectivity in the individual’s dorsal attention network (DAN), salience network (SN) and executive control network (ECN), within a month of their cardiac arrest and was followed up with for a year. Stevens and colleagues used multivariable modeling to map the association between connectivity measures, structural changes and principal outcomes in each patient, with a primary endpoint of cerebral performance at 12 months.

“By analyzing functional MRI data, we are able to see where brain network disruption is occurring, and determine how these changes relate to the likelihood of recovery from brain damage,” Stevens said in a release from Johns Hopkins Medicine.

A year after their cardiac arrests, 11 patients recorded a favorable outcome—defined as a cerebral performance category minimum of 1 or 2—following their MR imaging. Patients with a favorable outcome tended to have higher within-DMN connectivity and greater anticorrelation between SN and DMN and between SN and ECN when compared with patients who didn’t show an optimal outcome, Stevens and co-authors reported. Anticorrelation of SN-DMN was a strong predictor of more accurate outcomes, while fluid-attenuated inversion recovery and diffusion-weighted imaging scores fell behind.

Lead author Haris Sair, MD, said in the Johns Hopkins release these results suggest a novel biomarker: that MR imaging following cardiac arrest could greatly improve the accuracy of predicted outcomes for individual patients.

“These findings highlight a potential realm of precision medicine using brain network biomarkers that are discriminative and predictive of outcomes,” he said. “In the future, connectivity biomarkers may help guide new therapies for targeted treatment to improve brain function.”