Abstract #1642

Quantitation of Changes in Cerebral Blood Flow & Longitudinal Relaxation Rate (R1 =1/T1) Induced by Mild Hyperoxia

Hajime Tamura¹, Tatsuo Nagasaka², Kazuki Shimada², Junki Nishikata¹, Miho Shidahara¹, Shunji Mugikura³, Yoshio Machida⁴

¹Department of Medical Physics, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, Japan; ²Department of Radiology, Tohoku University Hospital, Sendai, Miyagi, Japan; ³Department of Diagnostic Radiology, Tohoku University Hospital, Sendai, Miyagi, Japan; ⁴Department of Medical Imaging & Applied Radiology, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, Japan

Decreases in blood flow (CBF) and T₁ during hyperoxia are affected by arterial pressure of carbon dioxide as well as that of oxygen (PaO₂). To extract those effects of PaO₂ and to examine if the changes in R₁ relate to the changes in CBF, serial R₁ and CBF maps were obtained during normoxia-hyperoxia epochs and analyzed with a linear model. Thus the effects of PaO₂ on R₁ and CBF were obtained. However, no significant correlation was observed between them (P = 0.18), which might imply that the ratio of CBF to metabolic rate of oxygen does not change during hyperoxia.