基于磁共振成像的肾血流量估计中的偏倚和精度：通过三角测量评估。

Bias and Precision in Magnetic Resonance Imaging-Based Estimates of Renal Blood Flow: Assessment by Triangulation.

机构信息

Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK.

Leeds Teaching Hospitals NHS Trust, Leeds, UK.

出版信息

J Magn Reson Imaging. 2022 Apr;55(4):1241-1250. doi: 10.1002/jmri.27888. Epub 2021 Aug 16.

DOI:10.1002/jmri.27888

PMID:34397124

Abstract

BACKGROUND

Renal blood flow (RBF) can be measured with dynamic contrast enhanced-MRI (DCE-MRI) and arterial spin labeling (ASL). Unfortunately, individual estimates from both methods vary and reference-standard methods are not available. A potential solution is to include a third, arbitrating MRI method in the comparison.

PURPOSE

To compare RBF estimates between ASL, DCE, and phase contrast (PC)-MRI.

STUDY TYPE

Prospective.

POPULATION

Twenty-five patients with type-2 diabetes (36% female) and five healthy volunteers (HV, 80% female).

FIELD STRENGTH/SEQUENCES: A 3 T; gradient-echo 2D-DCE, pseudo-continuous ASL (pCASL) and cine 2D-PC.

ASSESSMENT

ASL, DCE, and PC were acquired once in all patients. ASL and PC were acquired four times in each HV. RBF was estimated and split-RBF was derived as (right kidney RBF)/total RBF. Repeatability error (RE) was calculated for each HV, RE = 1.96 × SD, where SD is the standard deviation of repeat scans.

STATISTICAL TESTS

Paired t-tests and one-way analysis of variance (ANOVA) were used for statistical analysis. The 95% confidence interval (CI) for difference between ASL/PC and DCE/PC was assessed using two-sample F-test for variances. Statistical significance level was P < 0.05. Influential outliers were assessed with Cook's distance (D > 1) and results with outliers removed were presented.

RESULTS

In patients, the mean RBF (mL/min/1.73m ) was 618 ± 62 (PC), 526 ± 91 (ASL), and 569 ± 110 (DCE). Differences between measurements were not significant (P = 0.28). Intrasubject agreement was poor for RBF with limits-of-agreement (mL/min/1.73m ) [-687, 772] DCE-ASL, [-482, 580] PC-DCE, and [-277, 460] PC-ASL. The difference PC-ASL was significantly smaller than PC-DCE, but this was driven by a single-DCE outlier (P = 0.31, after removing outlier). The difference in split-RBF was comparatively small. In HVs, mean RE (±95% CI; mL/min/1.73 m ) was significantly smaller for PC (79 ± 41) than for ASL (241 ± 85).

CONCLUSIONS

ASL, DCE, and PC RBF show poor agreement in individual subjects but agree well on average. Triangulation with PC suggests that the accuracy of ASL and DCE is comparable.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

摘要

背景

肾血流量（RBF）可以通过动态对比增强磁共振成像（DCE-MRI）和动脉自旋标记（ASL）来测量。不幸的是，这两种方法的个体估计值存在差异，并且没有参考标准方法。一个潜在的解决方案是在比较中纳入第三种仲裁 MRI 方法。

目的

比较 ASL、DCE 和相位对比（PC）-MRI 之间的 RBF 估计值。

研究类型

前瞻性。

人群

25 名 2 型糖尿病患者（36%为女性）和 5 名健康志愿者（HV，80%为女性）。

磁场强度/序列：3T；梯度回波 2D-DCE、伪连续 ASL（pCASL）和电影 2D-PC。

评估

所有患者均进行一次 ASL、DCE 和 PC 采集。每个 HV 中均采集 4 次 ASL 和 PC。估计 RBF 并得出分割 RBF（右肾 RBF/总 RBF）。为每个 HV 计算重复测量误差（RE），RE=1.96×SD，其中 SD 是重复扫描的标准差。

统计检验

使用配对 t 检验和单因素方差分析（ANOVA）进行统计分析。使用两样本 F 检验评估 ASL/PC 和 DCE/PC 之间差异的 95%置信区间（CI）。统计显著性水平为 P<0.05。使用库克距离（D>1）评估有影响力的离群值，并呈现去除离群值后的结果。

结果

在患者中，平均 RBF（mL/min/1.73m）为 618±62（PC）、526±91（ASL）和 569±110（DCE）。测量值之间无显著差异（P=0.28）。RBF 的个体内一致性较差，其界限（mL/min/1.73m）为[-687，772] DCE-ASL、[-482，580] PC-DCE 和[-277，460] PC-ASL。PC-ASL 与 PC-DCE 的差异显著较小，但这是由单个 DCE 离群值驱动的（P=0.31，去除离群值后）。分割 RBF 的差异相对较小。在 HV 中，PC 的平均 RE（±95%CI；mL/min/1.73m）明显小于 ASL（79±41）（P<0.05）。