Chan Michael W, Nathanael George, Kis Antonella, Amirabadi Afsaneh, Zhong Anguo, Rayner Tammy, Weiss Ruth, Detzler Garry, Jong Roland, Gahunia Harpal, Moineddin Rahim, Crawley Adrian, Doria Andrea S
Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Ave., Toronto, Canada, M5G 1X8.
Pediatr Radiol. 2014 May;44(5):566-75. doi: 10.1007/s00247-013-2844-5. Epub 2013 Dec 24.
Blood-oxygen-level-dependent (BOLD) MRI has the potential to identify regions of early hypoxic and vascular joint changes in inflammatory arthritis. There is no standard protocol for analysis of BOLD MRI measurements in musculoskeletal disorders.
To optimize the following BOLD MRI reading parameters: (1) statistical threshold values (low, r > 0.01 versus high, r > 0.2); (2) summary measures of BOLD contrast (percentage of activated voxels [PT%] versus percentage signal difference between on-and-off signal intensities [diff_on_off]); and (3) direction of BOLD response (positive, negative and positive + negative).
Using BOLD MRI protocols at 1.5 T, arthritic (n = 21) and contralateral (n = 21) knees of 21 juvenile rabbits were imaged at baseline and on days 1, 14 and 28 after a unilateral intra-articular injection of carrageenan. Nine non-injected rabbits served as external control knees (n = 18). By comparing arthritic to contralateral knees, receiver operating characteristic curves were used to determine diagnostic accuracy.
Using diff_on_off and positive + negative responses, a threshold of r > 0.01 was more accurate than r > 0.2 (P = 0.03 at day 28). Comparison of summary measures yielded no statistically significant difference (P > 0.05). Although positive + negative (AUC = 0.86 at day 28) and negative responses (AUC = 0.90 at day 28) for PT% were the most diagnostically accurate, positive + negative responses for diff_on_off (AUC = 0.78 at day 28) also had acceptable accuracy.
The most clinically relevant reading parameters included a lower threshold of r > 0.01 and a positive + negative BOLD response. We propose that diff_on_off is a more clinically relevant summary measure of BOLD MRI, while PT% can be used as an ancillary measure.
血氧水平依赖（BOLD）磁共振成像有潜力识别炎性关节炎早期缺氧和血管关节改变的区域。在肌肉骨骼疾病中，尚无分析BOLD磁共振成像测量结果的标准方案。
优化以下BOLD磁共振成像的读片参数：（1）统计阈值（低，r>0.01与高，r>0.2）；（2）BOLD对比的汇总测量指标（激活体素百分比[PT%]与开-关信号强度之间的信号差异百分比[diff_on_off]）；以及（3）BOLD反应的方向（正向、负向和正向+负向）。
采用1.5T的BOLD磁共振成像方案，对21只幼年兔的患侧（n=21）膝关节和对侧（n=21）膝关节在基线时以及单侧关节内注射角叉菜胶后第1天、14天和28天进行成像。9只未注射的兔子作为外部对照膝关节（n=18）。通过比较患侧膝关节与对侧膝关节，使用受试者工作特征曲线来确定诊断准确性。
使用diff_on_off和正向+负向反应时，r>0.01的阈值比r>0.2更准确（第28天时P=0.03）。汇总测量指标的比较未产生统计学显著差异（P>0.05）。虽然PT%的正向+负向反应（第28天时AUC=0.86）和负向反应（第28天时AUC=0.90）诊断准确性最高，但diff_on_off的正向+负向反应（第28天时AUC=0.78）也具有可接受的准确性。
最具临床相关性的读片参数包括较低的r>0.01阈值和正向+负向的BOLD反应。我们建议diff_on_off是BOLD磁共振成像更具临床相关性的汇总测量指标，而PT%可作为辅助测量指标。
