Sulcal hyperintensity on fluid-attenuated inversion recovery imaging in acute ischemic stroke patients treated with intra-arterial thrombolysis: Iodinated contrast media as its possible cause and the association with hemorrhagic transformation

Objective: To investigate the effect of iodinated contrast medium on sulcal hyperintensity on fluid-attenuated inversion recovery (FLAIR) imaging immediately after intra-arterial thrombolysis in patients with acute ischemic stroke and to determine whether it may be associated with subsequent hemorrhagic transformation (HT). Methods: Fourteen consecutive patients with acute ischemic stroke who were treated with intra-arterial thrombolysis were enrolled. All patients underwent noncontrast computed tomography (NCT) and diffusion-weighted (DWI), perfusion-weighted, gradient-recalled echo (GRE), and gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI). Immediate follow-up NCT and MRI (T2-weighted, FLAIR, GRE, DWI, perfusion-weighted, T1-weighted, and gadolinium-enhanced T1-weighted) were obtained and evaluated to determine the presence of sulcal hyperintensity or subarachnoid hemorrhage (SAH). The same follow-up images were obtained on days 1, 3, and 7 and evaluated to determine HT. Results: Sulcal hyperintensity was found in 8 (57.1%) of 14 patients and was seen as hyperattenuation on immediate follow-up NCT and as hyperintensity on T1-weighted images in 4 (50%) of 8 patients. It may be suggested that the sulcal hyperattenuation was responsible for the sulcal hyperintensity, considering signal intensity and follow-up imaging. All patients with sulcal hyperintensity showed enhancement in the corresponding gyri on gadolinium-enhanced T1-weighted imaging. Hemorrhagic transformation developed in 5 of 8 patients with sulcal hyperintensity and in 1 of 4 patients without (P = 0.031). Conclusions: In acute ischemic patients treated with intra-arterial thrombolysis, sulcal hyperintensity on FLAIR imaging may be caused by iodinated contrast medium, which should not be considered SAH. Sulcal hyperintensity is significantly associated with subsequent HT.