Temporal evolution of the signal intensity of hyper-acute ischemic lesions in a canine stroke model: influence of hyperintense acute reperfusion marker.

Abstract

To assess the influence of the hyperintense acute reperfusion marker (HARM) on the relative signal intensity (rSI) and apparent diffusion coefficient (ADC) of hyper-acute ischemic lesions in a canine stroke model. Middle cerebral artery occlusion models were established using autologous clot embolization. Diffusion-weighted (DW) and fluid-attenuated inversion recovery (FLAIR) imaging was performed at 1, 2, 3, 4.5 and 6h after embolization. HARM was defined as the delayed enhancement of cerebrospinal fluid on the subsequent FLAIR images after contrast media used. Twenty-four stroke models were successfully established and divided into the HARM (n=16) and No-HARM group (n=8). No significant differences were found in the rSI on DWI (b0 and b1000 map) and relative ADC between the two groups at each time point after embolization (all P>0.05). There were no significant differences in the rSI on FLAIR at 1 and 2h after embolization between the two groups (P>0.05), while the HARM group showed significantly higher rSI on FLAIR than the No-HARM group at 3, 4.5 and 6h after embolization (P=0.044, 0.036 and 0.001, respectively). HARM should be noted during the quantitative analysis of FLAIR images in future clinical practice.