Alterations in Cerebrospinal Fluid Density Following Contrast Administration in Patients With Acute Ischemic Stroke.

INTRODUCTION: The degree of iodine clearance from the parenchyma in acute ischemic stroke (AIS) has not been determined. The aim of our study was to measure changes in cerebrospinal fluid (CSF) density in patients with AIS relative to controls. METHODS: This is a retrospective cohort study from a single tertiary stroke center, including any patient who underwent CT angiography (CTA) and EVT and then follow-up noncontrast CT (NCCT) after 12-36 h. Control group included nonstroke patients who underwent CTA and a NCCT after 12-36 h. The density of CSF in Hounsfield units (HU) was measured in the frontal horns of lateral ventricles and in the third ventricle and was compared between baseline and follow-up NCCT (ΔHU), as well as between groups. Paired t-tests and multivariable linear regression analysis were utilized for data analysis. RESULTS: Altogether, 134 patients with AIS and 46 controls were included. In the AIS group, we found median (IQR) ΔHU of 1 (-0.34, 2.33) compared with -0.33 (-1, 0.33) in controls (p < 0.01). Early ischemic changes and onset-to-recanalization times remained significant for ΔHU following multivariable analysis. DISCUSSION: Our findings suggest that iodine contrast administration in patients with AIS leads to increased CSF density, potentially through the glymphatic clearance systems.