Which pathologic staining method can visualize the hyperacute infarction lesion identified by diffusion MRI?: A comparative experimental study.

BACKGROUND:The study aimed to establish a staining method that could delineate the macroscopic lesion boundary of a hyperacute infarction depicted by diffusion-weighted MRI (DWI) and to validate the infarction boundary by comparing different staining methods. NEW METHOD:Thirteen rats with 1 -h middle cerebral artery (MCA) infarction were included. Five different staining methods (Hematoxylin and eosin (H&E), Nissl, 2,3,5-triphenyltetrazolium hydrochloride (TTC), microtubule associated protein 2 (MAP2), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) stains) were used to identify whether the hyperacute infarction could be histopathologically identified. Dice indices were compared to evaluate similarities in the lesion area ascertained by DWI and the staining methods. Through macroscopic lesion delineation, each region was subdivided into abnormal regions in all three stains (ROIA), abnormal in two stains (ROIB), and abnormal in only one (ROIC). Microscopic cellular changes were evaluated and graded according to each region. RESULTS:Mean Dice indices of the H&E stain were significantly higher than those of the Nissl- and MAP2-stained specimens (0.83 ± 0.052, 0.58 ± 0.107, and 0.56 ± 0.059, respectively; p = 0.000). Grading scores for ROIs in the DWI abnormal lesions varied by region: ROIA exhibited the most severe damage [median (IQR), 3 (1)], followed respectively by ROIB [median (IQR), 2 (0)] and ROIC [median (IQR), 1 (0)] COMPARISON WITH EXISTING METHODS: H&E stain best reflects 1 h hyperacute DWI abnormal lesions. CONCLUSIONS:H&E stain allowed for the macroscopic delineation of the 1 h DWI-abnormal lesions, while MAP2 and Nissl stains could only partially depict lesions.