DynamicMRIによる睡眠時無呼吸患者の解析 Predicting the presence and the severity of obstructive sleep apnea (OSA) with MRI findings
MRI所見から閉塞性睡眠時無呼吸 (OSA) の病態と重症度を予測するため、21例のOSA患者の睡眠中の上気道の状態を薬物睡眠下にDynamic MRIを用いて撮像した.覚醒時と睡眠時の画像における上・中・下咽頭の距離と面積を計測し, 気道と軟部組織の狭窄の程度の量的な解析を行った.睡眠中では, 各レベルにおいて気道の距離と面積は, 覚醒時よりも狭かった.AHIと酸素飽和度の低下は舌根部と下咽頭の気道の狭さと相関した.肥満は下咽頭の軟部組織と舌の体積に影響するのでOSAの重症度に影響を及ぼしていた.以上より, 睡眠時のDynamic MRIはOSAの狭窄部位と重症度を予測するために有用であり, 治療に活用できるものと考えられた.
To identify MRI findings that can predict the presence and the severity of obstructive sleep apnea (OSA), we studied 21 cases with OSA, using Dynamic MRI to evaluate the status of the upper airway during sleep.Scans were obtained at the rate of one image per 1 to 2 sec while the patients were asleep, using mitazolam 5mg i.v. We performed a quantitative analysis of the presence of occlusions and of the narrowing of the pharyngeal airway and soft tissue and compared the distance and area in each of the epi-, meso-, and hypopharynx levels in the awake and asleep conditions, using both airway images taken with a DICOM Viewer System as data.<BR>The correlation between AHI, Mean SaO<SUB>2</SUB>, Lowest SaO<SUB>2</SUB>, Body Mass Index (BMI), and the valueof each measurement was assessed. In sleep, each distance of the airway in the epi-, meso-, andhypopharynx was significantly narrower than the value in the awake condition. The severity of AHI and SaO<SUB>2</SUB> are significantly correlated with the width of the airway space at the base of the tongue andhypopharynx. Obesity is an important factor in OSA because it affects the volume of the tongue andof the soft tissue of the hypopharynx. Our data showed that is impossible to get information on thelevel of occlusion during sleep or on the severity of OSA by studying the patient in the awake condition.Therefore Dynamic MRI during sleep is useful to detect the level of occlusion during sleep and the severity of OSA, and this can assist in the treatment of OSA.
- 口腔・咽頭科 = Stomato-pharyngology
口腔・咽頭科 = Stomato-pharyngology 13(3), 389-394, 2001-06-01