Analysis of brain edema in RHAPSODY

Area of Science:

• Neurology
• Radiology
• Biomedical Engineering

Background:

• Cerebral edema is a critical secondary complication of acute ischemic stroke.
• The temporal dynamics and reliable imaging markers for cerebral edema remain incompletely understood.
• Net water uptake (NWU) has emerged as a potential novel imaging biomarker for edema.

Purpose of the Study:

• To investigate the time course of cerebral edema following acute ischemic stroke.
• To evaluate whether NWU provides unique information beyond traditional edema markers.
• To examine the association of NWU with other established imaging markers of edema.

Main Methods:

• Utilized data from the RHAPSODY trial cohort, including 65 patients with supratentorial ischemic lesions.
• Collected serial head CT and/or brain MRI scans at baseline and days 2, 7, 30, and 90.
• Measured four imaging markers: midline shift (MLS), hemisphere volume ratio (HVR), cerebrospinal fluid (CSF) volume, and NWU.

Main Results:

• Mass effect markers (MLS, HVR) peaked by day 7, normalized by day 30, and reversed by day 90.
• CSF volume changes correlated with MLS and HVR in the early phase post-stroke.
• Net water uptake (NWU) showed no significant association with other edema markers or baseline stroke volume, suggesting distinct pathophysiological relevance.

Conclusions:

• Traditional imaging markers (MLS, HVR, CSF volume) primarily reflect mass effect.
• Net water uptake (NWU) appears to represent lesional water concentration, a distinct process.
• These distinct imaging markers may offer complementary insights for future stroke edema research and therapeutic trials.