Proper fraction of inspired oxygen for reduction of oxygen-induced canine cerebrospinal fluid hyperintensity on fluid attenuation inversion recovery sequence using low-field magnetic resonance imaging

Moonjung JANG; Jaewoo HWANG; Jihye NAM; Dalhae KIM; Wongyun SON; Inhyung LEE; Mincheol CHOI; Junghee YOON

doi:10.1292/jvms.20-0060

Internal Medicine

Proper fraction of inspired oxygen for reduction of oxygen-induced canine cerebrospinal fluid hyperintensity on fluid attenuation inversion recovery sequence using low-field magnetic resonance imaging

Moonjung JANG, Jaewoo HWANG, Jihye NAM, Dalhae KIM, Wongyun SON, Inhyung LEE, Mincheol CHOI, Junghee YOON

Author information

Moonjung JANG
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
Jaewoo HWANG
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
Jihye NAM
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
Dalhae KIM
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
Wongyun SON
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
Inhyung LEE
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
Mincheol CHOI
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
Junghee YOON
College of Veterinary Medicine and the Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea

Keywords: cerebrospinal fluid, fluid attenuation inversion recovery, fraction of inspired oxygen, hyperintensity artifact, magnetic resonance imaging

JOURNAL OPEN ACCESS

2020 Volume 82 Issue 9 Pages 1321-1328

DOI https://doi.org/10.1292/jvms.20-0060

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Abstract

Oxygen-induced cerebrospinal fluid (CSF) hyperintensity artifact is inevitable in fluid attenuation inversion recovery (FLAIR) magnetic resonance (MR) images of anesthetized animals. This experimental study aimed to confirm the occurrence of this artifact on low-field magnetic resonance imaging (MRI), and to determine the fraction of inspired oxygen (FiO₂) that is safe and does not induce this artifact in canine brain MRI. Six healthy dogs underwent brain FLAIR MR scans under general anesthesia with 21%, 30%, 50%, 70%, and 100% FiO₂. The signal intensity (SI) ratio was calculated as the SI of CSF spaces divided by that of normalizing regions. The SI ratios of 21% FiO₂ images were significantly different from those of 100% FiO₂ images, indicating the presence of artifacts on 100% FiO₂ images. The SI ratios of 30% FiO₂ images were not significantly different from those of 21% FiO₂ images for any of CSF spaces. However, they were significantly different from those of 100% FiO₂ images in the cerebral sulci, third ventricle, interpeduncular cistern, mesencephalic aqueduct, and subarachnoid space at the level of the first cervical vertebra (P<0.05). All dogs had normal partial pressure of arterial oxygen (PaO₂) during inhalation of 30% FiO₂, while two dogs had low PaO₂ during inhalation of 21% FiO₂. Our findings support the hypothesis that high FiO₂ induces CSF hyperintensity artifact on low-field FLAIR MR images in dogs. FiO₂ of 30% is appropriate for obtaining brain FLAIR MR images with fewer artifacts in dogs.

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