CT perfusion-derived arterial input function dispersal versus echocardiographic left atrial enlargement in acute stroke

Arterial input function (AIF) dispersal on brain computed tomography (CT) perfusion reflects delayed cerebral contrast transit and is associated with reduced left ventricular ejection fraction (LVEF). We hypothesized that delayed contrast transit through the LA due to LA enlargement may prolong AIF, independent of LVEF.

We analyzed patients with ischemic stroke or transient ischemic attack from the prospective INSPIRE registry (December 2020-June 2024) who underwent multimodal CT including brain perfusion CT (CTP), as well as transthoracic echocardiography (TTE) within 90 days of stroke. On TTE, left atrial (LA) enlargement was defined as area ≥ 24 cm² and left ventricular ejection fraction (LVEF) as < 50%. Prolonged AIF dispersal from CTP was defined as ≥ 29 s from scan onset to the end of AIF (return to baseline). Multivariable logistic regression was performed, adjusted for clinical and cardiac covariates.

Among 172 patients, prolonged AIF was observed in 50 (29.1%), LA enlargement in 52 (30.2%), and reduced LVEF in 28 (16.3%). In multivariate analysis including both variables, LA enlargement (≥24 cm²: OR 3.76, 95% CI 1.66-8.52, p = 0.002) and reduced LVEF (OR 3.35, 95% CI 1.21-9.27, p = 0.020) were independently associated with prolonged AIF dispersal.

Both LA enlargement and reduced LVEF were associated with prolonged AIF dispersal, suggesting that AIF delay on CTP is a useful screening tool to identify stroke patients with cardiac dysfunction.