MRI of cerebral functional network connectivity in comatose patients who recently suffered cardiac arrest may help determine if they will recover cognitive abilities at one year, according to a new study published April 23 in Radiology.
Many patients exhibiting cardiac arrest are not conscious immediately after the event. Patients may stay comatose for even up to weeks after the event. This factor makes it difficult to gauge the patients’ long-term outcomes.
The researchers, lead author Robert D. Stevens, Johns Hopkins University School of Medicine in Baltimore, studied functional and structural MRIs of 46 comatose patients who experienced cardiac arrest, after an average of 12 days. The researchers sought to assess whether imaging brain connectivity after cardiac arrest was associated with both positive and negative long-term outcomes.
“The results demonstrate that abnormalities in long-range connectivity occur within and between canonical brain networks in the acute phase of anoxic brain injury, and these abnormalities are associated with long-term functional outcomes,” wrote Stevens and colleagues. “The link between functional connectivity and outcome was observed even alter adjustment in multivariable models and improved classification compared with postanoxic structural changes appreciate using morphologic acquisition sequences.”
Within and between-network connectivity was measured in dorsal attention network (DAN), default-mode network (DMN), salience network (SN) and executive control network (ECN) using seed-based analysis or resting-state functional MRI data. Structural changed identified with fluid attenuated inversion recovery and diffusion-weighted imaging sequences were analyzed using validated morphologic scales. The association between connectivity measures, structural changes and the principal outcome was explored with multivariable modeling.
The researchers found patients with better favorable outcomes had a greater preservation of connectivity and greater anti-correlation between salience network (SN) and default-mode network and between SN and executive control network (ECN), compared to patients with unfavorable outcomes.
“MRI performed in the acute phase after cardiac arrest indicates that network functional connectivity measures increase the accuracy of outcome prediction, which suggests a novel prognostic biomarker,” the authors concluded.
As a senior news writer for TriMed, Subrata covers cardiology, clinical innovation and healthcare business. She has a master’s degree in communication management and 12 years of experience in journalism and public relations.