Kamba M, Suto Y, Ohta Y, Inoue Y, Matsuda E
Department of Radiology, Tottori University Faculty of Medicine, Yonago, Japan.
Am J Respir Crit Care Med. 1997 Jul;156(1):296-8. doi: 10.1164/ajrccm.156.1.9611063.
Repeated apneic episodes during sleep may lead to cerebral damage in patients with obstructive sleep apnea (OSA). We performed proton magnetic resonance (MR) spectroscopic studies to examine cerebral metabolism in patients with OSA. We studied 15 healthy subjects and 23 patients with OSA who displayed no anatomical abnormalities on MR imaging. The patients were classified into two groups based on the results of polysomnography: mild OSA (11 patients) or moderate to severe OSA (12 patients). All the subjects were examined with two-dimensional chemical shift imaging. The N-acetylaspartate (NAA)/choline (Cho), NAA/creatine (Cre), and Cho/Cre ratios for cerebral cortex and white matter were calculated separately. A statistically significant intergroup difference was found for the NAA/Cho ratio in cerebral white matter (p < 0.005). This ratio was significantly lower in patients with moderate to severe OSA than in patients with mild OSA (p < 0.01) and healthy subjects (p < 0.01). Our findings indicate that cerebral metabolic changes occur in normal-appearing brain tissue in patients with moderate to severe OSA. The findings of a decreased NAA/Cho ratio suggests the presence of cerebral damage, probably caused by repeated apneic episodes. Proton MR spectroscopy may be useful for evaluating cerebral damage in patients with OSA.
睡眠期间反复出现的呼吸暂停发作可能导致阻塞性睡眠呼吸暂停（OSA）患者出现脑损伤。我们进行了质子磁共振（MR）波谱研究，以检查OSA患者的脑代谢情况。我们研究了15名健康受试者和23名在MR成像上未显示解剖学异常的OSA患者。根据多导睡眠图结果将患者分为两组：轻度OSA（11例患者）或中度至重度OSA（12例患者）。所有受试者均接受二维化学位移成像检查。分别计算大脑皮质和白质的N-乙酰天门冬氨酸（NAA）/胆碱（Cho）、NAA/肌酸（Cre）和Cho/Cre比值。发现脑白质中NAA/Cho比值存在统计学上的显著组间差异（p<0.005）。中度至重度OSA患者的该比值显著低于轻度OSA患者（p<0.01）和健康受试者（p<0.01）。我们的研究结果表明，中度至重度OSA患者外观正常的脑组织中会发生脑代谢变化。NAA/Cho比值降低的结果提示存在脑损伤，可能是由反复的呼吸暂停发作引起的。质子MR波谱可能有助于评估OSA患者的脑损伤。
