Hyperoxia-Induced ΔR 1 : MRI Biomarker of Histological Infarction in Acute Cerebral Stroke

• Published in: Korean journal of radiology Vol. 23; no. 4; pp. 446 - 454
• Main Authors: Park, Kye Jin, Suh, Ji-Yeon, Heo, Changhoe, Kim, Miyeon, Baek, Jin Hee, Kim, Jeong Kon
• Format: Journal Article
• Language: English
• Published: Korea (South) 대한영상의학회 01.04.2022
• Subjects: Animals; Biomarkers; Humans; Hyperoxia - complications; Infarction; Magnetic Resonance Imaging; Rats; Stroke - pathology; 방사선과학; Biomarker; Infarction; MRI; Acute stroke; Hyperoxia-induced ΔR1
• ISSN: 1229-6929; 2005-8330
• DOI: 10.3348/kjr.2021.0477

To evaluate whether hyperoxia-induced ΔR (hyperO ΔR ) can accurately identify histological infarction in an acute cerebral stroke model. In 18 rats, MRI parameters, including hyperO ΔR , apparent diffusion coefficient (ADC), cerebral blood flow and volume, and F-fluorodeoxyglucose uptake on PET were measured 2.5, 4.5, and 6.5 hours after a 60-minutes occlusion of the right middle cerebral artery. Histological examination of the brain was performed immediately following the imaging studies. MRI and PET images were co-registered with digitized histological images. The ipsilateral hemisphere was divided into histological infarct (histological cell death), non-infarct ischemic (no cell death but ADC decrease), and non-ischemic (no cell death or ADC decrease) areas for comparisons of imaging parameters. The levels of hyperO ΔR and ADC were measured voxel-wise from the infarct core to the non-ischemic region. The correlation between areas of hyperO ΔR -derived infarction and histological cell death was evaluated. HyperO ΔR increased only in the infarct area ( ≤ 0.046) compared to the other areas. ADC decreased stepwise from non-ischemic to infarct areas ( = 0.002 at all time points). The other parameters did not show consistent differences among the three areas across the three time points. HyperO ΔR sharply declined from the core to the border of the infarct areas, whereas there was no change within the non-infarct areas. A hyperO ΔR value of 0.04 s was considered the criterion to identify histological infarction. ADC increased gradually from the infarct core to the periphery, without a pronounced difference at the border between the infarct and non-infarct areas. Areas of hyperO ΔR higher than 0.04 s on MRI were strongly positively correlated with histological cell death ( = 0.862; < 0.001). HyperO ΔR may be used as an accurate and early (2.5 hours after onset) indicator of histological infarction in acute stroke.