Objectives-To determine the relation between severity of obstructive sleep apnoea (OSA) and degree of cerebral metabolic impairment. Methods-Fifty five patients with habitual snoring and excessive daytime sleepiness underwent standard overnight polysomnography and magnetic resonance spectroscopy separately. Proton MR spectra were measured with two dimensional chemical shift imaging (repetition time; 1500 ms, echo time; 135 ms). Severity of cerebral metabolic impairment was assessed by the N-acetylaspartate (NAA)/choline ratios for the cerebral cortex and white matter. Severity of OSA was assessed by the apnoea-hypopnoea index (AHI) and the minimum value of peripheral oxyhaemoglobin saturation. All patients were evaluated for the presence or absence of comobidities including hypertension, cardiac disease, diabetes mellitus, and hyperlipidaemia. Univariate analysis of variance (ANOVA) and mulitple linear regression analysis were used for statistical analyses. Results-Univariate ANOVA disclosed significant eVects of AHI, age, and the presence or absence of hypertension on the NAA/choline ratio for cerebral white matter (p=0.011, p=0.028, p=0.0496, respectively). The AHI had a significant negative association with the NAA/choline ratio for cerebral white matter, independent of age and the presence or absence of cardiac disease, in the final multivariate regression model (standardised partial regression coeYcient=−0.417, p<0.001). No significant relation was found between severity of OSA and the NAA/choline ratio for the cerebral cortex. Age alone had a significant eVect on the NAA/choline ratio for the cerebral cortex on univariate ANOVA (p<0.001) and a significant negative association with the NAA/choline ratio for the cerebral cortex in the regression model (r=−0.552, p<0.001). Conclusions-A significant relation exists between AHI and the degree of metabolic impairment in cerebral white matter in patients with OSA. (J Neurol Neurosurg Psychiatry 2001;71:334-339) Keywords: magnetic resonance spectroscopy; sleep apnoea syndromes; white matter disease Repeated sleep apnoeic episodes may lead to CNS impairment in patients with obstructive sleep apnoea (OSA). Excessive daytime sleepiness and cognitive and emotional deficits are common daytime symptoms of OSA.1-6 A multiple sleep latency test and maintenance of wakefulness test have been used to quantify daytime sleepiness.7 8 Neuropsychological and electrophysiological tests have been used to quantify cognitive dysfunction.1-6 9-11 Hypoxic brain damage and fragmentation of sleep are generally thought to be causes of these deficits. 2-6 8 9Magnetic resonance spectroscopy (MRS) enables non-invasive evaluation of focal metabolic changes in various conditions aVecting the CNS. We previously reported cerebral metabolic changes in patients with OSA.12 The N-acetylaspartate (NAA)/choline ratio for cerebral white matter was significantly lower in patients with moderate to severe OSA than in patients with mild OSA and healthy subjects, indicating axonal injury or gli...

Sonographic subcutaneous or visceral fat index could be an easily measured and inexpensive indicator for the assessment of fat distribution instead of CT or MR imaging.

No abstract

Serial images of the swallowing motions of 10 healthy volunteers were taken using the Turbo-fast low angle shot (FLASH) magnetic resonance (MR) imaging sequence, while the subject swallowed an oral contrast agent containing ferric ammonium citrate. In all cases, the flow of the contrast agent and the motion of the organs in the oral cavity and the pharynx during swallowing could be observed. High-speed MR imaging combined with an oral positive contrast agent has the potential to evaluate accurately swallowing motion.