Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pediatrics, Division of Nephrology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Pediatr Transplant. 2023 Aug;27(5):e14540. doi: 10.1111/petr.14540. Epub 2023 May 11.
Noninvasive alternatives to biopsy for assessment of interstitial fibrosis and tubular atrophy (IFTA), the major determinant of kidney transplant failure, remain profoundly limited. Elastography is a noninvasive technique that propagates shear waves across tissues to measure their stiffness. We aimed to test utility of elastography for early detection of IFTA in pediatric kidney allografts.
We compared ultrasound (USE) and MR elastography (MRE) stiffness measurements, performed on pediatric transplant recipients referred for clinically indicated biopsies, and healthy controls.
Ten transplant recipients (median age 16 years) and eight controls (median age 16.5 years) were enrolled. Three transplant recipients had "stable" allografts and seven had Banff Grade 1 IFTA. Median time from transplantation to biopsy was 12 months. Mean estimated glomerular filtration rate was 61.5 mL/min/1.73m by creatinine-cystatin-C CKiD equation at time of biopsy. Mean stiffness, calculated through one-way ANOVA, was higher for IFTA allografts (23.4 kPa USE/5.6 kPa MRE) than stable allografts (13.7 kPa USE/4.4 kPa MRE) and controls (9.1 kPa USE/3.6 kPa MRE). Pearson's coefficient between USE and MRE stiffness values was strong (r = .97). AUC for fibrosis prediction in transplanted kidneys was high for both modalities (0.91 USE and 0.89 MRE), although statistically nonsignificant (p > .05). Stiffness cut-off values for USE and MRE were 13.8 kPa and 4.6 kPa, respectively. Both values yielded a sensitivity of 100% but USE specificity (72%) was slightly higher than MRE (67%).
Elastography shows potential for detection of low-grade IFTA in allografts although a larger sample is imperative for clinical validation.
对于评估间质纤维化和肾小管萎缩（IFTA）的替代活检方法，这是导致肾移植失败的主要因素，目前仍然非常有限。弹性成像是一种非侵入性技术，可在组织中传播剪切波以测量其硬度。我们旨在测试弹性成像在早期检测儿科肾移植中 IFTA 的效用。
我们比较了超声（USE）和磁共振弹性成像（MRE）在因临床需要进行活检的儿科移植受者和健康对照者中的硬度测量值。
共纳入 10 名移植受者（中位年龄 16 岁）和 8 名对照者（中位年龄 16.5 岁）。3 名移植受者的移植物为“稳定”，7 名移植受者为 Banff 1 级 IFTA。活检时，从移植到活检的中位时间为 12 个月。通过 CKiD 方程计算的肌酐-胱抑素 C 估计肾小球滤过率为 61.5 mL/min/1.73m。通过单向方差分析计算的平均硬度，IFTA 移植物较高（USE 为 23.4kPa/MRE 为 5.6kPa），稳定移植物（USE 为 13.7kPa/MRE 为 4.4kPa）和对照组（USE 为 9.1kPa/MRE 为 3.6kPa）。USE 和 MRE 硬度值之间的 Pearson 系数较强（r=0.97）。两种模态对移植肾纤维化的预测 AUC 均较高（USE 为 0.91，MRE 为 0.89），尽管统计学上无显著性差异（p＞0.05）。USE 和 MRE 的硬度截断值分别为 13.8kPa 和 4.6kPa。两种值的灵敏度均为 100%，但 USE 的特异性（72%）略高于 MRE（67%）。
尽管需要更大的样本量进行临床验证，但弹性成像在检测移植物中的低级别 IFTA 方面具有潜力。
