Background:Monitoring for acute allograft rejection improves outcomes after cardiac transplantation. Endomyocardial biopsy is the gold standard test defining rejection, but carries risk and has limitations. Cardiac magnetic resonance T2 mapping may be able to predict rejection in adults, but has not been studied in children. Our aim was to evaluate T2 mapping in identifying paediatric cardiac transplant patients with acute rejection.Methods:Eleven paediatric transplant patients presenting 18 times were prospectively enrolled for non-contrast cardiac magnetic resonance at 1.5 T followed by endomyocardial biopsy. Imaging included volumetry, flow, and T2 mapping. Regions of interest were manually selected on the T2 maps using the middle-third technique in the left ventricular septal and lateral wall in a short-axis and four-chamber slice. Mean and maximum T2 values were compared with Student’s t-tests analysis.Results:Five cases of acute rejection were identified in three patients, including two cases of grade 2R on biopsy and three cases of negative biopsy treated for clinical symptoms attributed to rejection (new arrhythmia, decreased exercise capacity). A monotonic trend between increasing T2 values and higher biopsy grades was observed: grade 0R T2 53.4 ± 3 ms, grade 1R T2 54.5 ms ± 3 ms, grade 2R T2 61.3 ± 1 ms. The five rejection cases had significantly higher mean T2 values compared to cases without rejection (58.3 ± 4 ms versus 53 ± 2 ms, p = 0.001).Conclusions:Cardiac magnetic resonance with quantitative T2 mapping may offer a non-invasive method for screening paediatric cardiac transplant patients for acute allograft rejection. More data are needed to understand the relationship between T2 and rejection in children.

中文翻译：

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定量心脏磁共振 T2 成像提供了无创预测儿童急性同种异体移植排斥反应的能力

背景：监测急性同种异体移植物排斥反应可改善心脏移植后的结果。心内膜心肌活检是定义排斥反应的金标准测试，但具有风险和局限性。心脏磁共振 T2 映射可能能够预测成人的排斥反应，但尚未在儿童中进行研究。我们的目的是评估 T2 映射在识别患有急性排斥反应的儿科心脏移植患者中的作用。方法：11 名出现 18 次的儿科移植患者被前瞻性纳入 1.5 T 的非对比心脏磁共振检查，然后进行心内膜心肌活检。成像包括容积、流量和 T2 映射。使用短轴和四腔切片中左室间隔和侧壁的中间三分之一技术在 T2 图上手动选择感兴趣的区域。将 T2 值的平均值和最大值与学生 t 检验分析进行比较。 结果：3 例患者中发现 5 例急性排斥反应，其中 2 例活检为 2R 级，3 例因排斥反应的临床症状而活检阴性（新心律失常，运动能力下降）。观察到增加的 T2 值和更高的活检等级之间的单调趋势：0R T2 级 53.4 ± 3 ms，1R T2 级 54.5 ms ± 3 ms，2R T2 级 61.3 ± 1 ms。与没有排斥的病例相比，5 个排斥病例的平均 T2 值显着更高（58.3 ± 4 ms 对 53 ± 2 ms，p = 0.001）。结论：心脏磁共振定量 T2 映射可能为筛查儿科提供一种非侵入性方法用于急性同种异体移植排斥的心脏移植患者。