Solga Steven F, Horska Alena, Hemker Susanne, Crawford Stephen, Diggs Charalett, Diehl Anna Mae, Brancati Frederick L, Clark Jeanne M
Department of Medicine, Division of Gastroenterology, Johns Hopkins University, Baltimore, MD 21205, USA.
Liver Int. 2008 May;28(5):675-81. doi: 10.1111/j.1478-3231.2008.01705.x. Epub 2008 Mar 4.
BACKGROUND/AIMS: Magnetic resonance spectroscopy (MRS) measures hepatic fat and adenosine triphosphate (ATP), but magnetic resonance studies are challenging in obese subjects. We aimed to evaluate the inter- and intrarater reliability and stability of hepatic fat and ATP measurements in a cohort of overweight and obese adults.
We measured hepatic fat and ATP using proton MRS ((1)H MRS) and phosphorus MRS ((31)P MRS) at baseline in adults enrolled in the Action for Health in Diabetes (Look AHEAD) clinical trial at one site. Using logistic regression, we determined factors associated with successful MRS data acquisition. We calculated the intra- and inter-rater reliability for hepatic fat and ATP based on 20 scans analysed twice by two readers. We also calculated the stability of these measures three times on five healthy volunteers.
Of 244 participants recruited into our ancillary study, 185 agreed to MRS. We obtained usable hepatic fat data from 151 (82%) and ATP data from 105 (58%). Obesity was the strongest predictor of failed data acquisition; every unit increase in the body mass index reduced the likelihood of successful fat data by 11% and ATP data by 14%. The inter- and intrarater reliability were excellent for fat (intraclass correlation coefficient=0.99), but substantially more variable for ATP. Fat measures appeared relatively stable, but this was less true for ATP.
Obesity can hinder (1)H and (31)P MRS data acquisition and subsequent analysis. This impact was greater for hepatic ATP than hepatic fat.
背景/目的：磁共振波谱（MRS）可测量肝脏脂肪和三磷酸腺苷（ATP），但磁共振研究在肥胖受试者中具有挑战性。我们旨在评估一组超重和肥胖成年人肝脏脂肪和ATP测量的评分者间及评分者内信度和稳定性。
在糖尿病健康行动（Look AHEAD）临床试验的一个站点，我们使用质子磁共振波谱（（1）H MRS）和磷磁共振波谱（（31）P MRS）在基线时测量了成年人的肝脏脂肪和ATP。使用逻辑回归，我们确定了与成功获取MRS数据相关的因素。我们基于两位读者对20次扫描进行两次分析，计算了肝脏脂肪和ATP的评分者内及评分者间信度。我们还在五名健康志愿者身上对这些测量进行了三次稳定性计算。
在招募到我们辅助研究的244名参与者中，185人同意进行MRS。我们从151人（82%）获得了可用的肝脏脂肪数据，从105人（58%）获得了ATP数据。肥胖是数据获取失败的最强预测因素；体重指数每增加一个单位，成功获取脂肪数据的可能性降低11%，成功获取ATP数据的可能性降低14%。脂肪的评分者间及评分者内信度极佳（组内相关系数 = 0.99），但ATP的信度变化更大。脂肪测量结果相对稳定，但ATP并非如此。
肥胖会阻碍（1）H和（31）P MRS数据的获取及后续分析。这种影响对肝脏ATP比对肝脏脂肪更大。
