Imaging Research Laboratories, Robarts Research Institute, London, Canada N6A 5K8.
Acad Radiol. 2011 Aug;18(8):1006-13. doi: 10.1016/j.acra.2011.03.005. Epub 2011 May 4.
To better understand imaging measurement precision and reproducibility and to provide guidance for measurements in individual cystic fibrosis (CF) subjects, we evaluated CF adults on two occasions 7 ± 2 days apart using spirometry, plethysmography, and hyperpolarized helium-3 ((3)He) magnetic resonance imaging (MRI).
Twelve CF subjects underwent spirometry, plethysmography, and (3)He MRI twice within 7 ± 2 days, reporting (3)He ventilation defect volume (VDV) and ventilation defect percent (VDP).
Based on measurement variability, the smallest detectable difference (SDD) for (3)He VDV and VDP was determined to be 120 mL and 2%, respectively. Although no significant difference in spirometry or plethysmography was detected after 7 days, there was a significant difference in mean (3)He VDV (130 mL ± 250 mL, P < .0001) and VDP (3% ± 4%, P < .0001), although baseline and 7-day measurements were highly correlated (VDV: r = .85, P = .001; VDP: r = .94, P < .0001). We estimated the sample sizes required to detect a 5%/7%/10% change in (3)He VDP as 60/15/5 subjects per group.
Hyperpolarized (3)He MRI VDP measurement precision resulted in an SDD for individual CF subjects of 2%, indicating that changes greater than this can be attributed to lung functional changes and not measurement error. After 7 days, significant changes in mean (3)He VDV and VDP were detected and these changes were not reflected by changes in pulmonary function measurements. These findings demonstrate the high sensitivity and reproducibility of (3)He MRI functional imaging that permits the use of relatively small samples sizes in CF interventional studies.
为了更好地理解影像学测量的精密度和可重复性，并为个体囊性纤维化（CF）患者的测量提供指导，我们对 12 例 CF 成人患者进行了两次相隔 7±2 天的肺功能、体描法和超极化氦-3（3He）磁共振成像（MRI）检查。
12 例 CF 患者在 7±2 天内两次接受肺功能、体描法和 3He MRI 检查，报告 3He 通气缺陷体积（VDV）和通气缺陷百分比（VDP）。
基于测量变异性，确定 3He VDV 和 VDP 的最小可检测差异（SDD）分别为 120 mL 和 2%。尽管 7 天后肺功能和体描法检查无显著差异，但 3He VDV（130 mL±250 mL，P<.0001）和 VDP（3%±4%，P<.0001）的平均值有显著差异，尽管基线和 7 天的测量值高度相关（VDV：r=0.85，P=0.001；VDP：r=0.94，P<.0001）。我们估计，要检测 3He VDP 5%/7%/10%的变化，每组需要 60/15/5 例患者。
超极化 3He MRI VDP 测量的精密度导致 CF 个体的 SDD 为 2%，表明大于该值的变化可归因于肺功能变化，而不是测量误差。7 天后，3He VDV 和 VDP 的平均值发生了显著变化，而这些变化并没有反映在肺功能测量值的变化中。这些发现表明 3He MRI 功能成像具有高灵敏度和可重复性，可在 CF 介入研究中使用相对较小的样本量。
