Impact of airway management strategies on magnetic resonance image quality

Background Use of general anaesthesia or deep sedation during magnetic resonance imaging (MRI) studies leads to pharyngeal muscle relaxation, often resulting in snoring and subsequent vibrations with head micromotion. Given that MRI is very susceptible to motion, this causes artifacts and image quality degradation. The purpose of our study was to determine the effectiveness of different airway management techniques in overcoming micromotion-induced MRI artifacts. Methods After obtaining institutional review board approval, we conducted a retrospective study on the image quality of central nervous system MRI studies in nine patients who had serial MRIs under general anaesthesia. All data were obtained from electronic records. We evaluated the following airway techniques: use of no airway device (NAD); oral, nasal, or supraglottic airway (SGA); or tracheal tube. To assess MRI quality, we developed a scoring system with a combined score ranging from 6 to 30. We used the linear mixed model to account for patient-dependent confounders. Results We assessed 85 MRI studies from nine patients: 48 NAD, 27 SGA, four oral, four nasal, and two tracheal tube. Arithmetical mean combined scores were 21.6, 27.6, 20.3, 15.3, and 29.5, respectively. The estimated mean combined scores for the NAD and SGA cohorts were 22.0 and 27.3, respectively, showing that SGA use improved the combined score by 5.3 (P<0.0001). Conclusions The use of an SGA during MRI studies under general anaesthesia or deep sedation significantly improves image quality.