Estimation of renal extraction fraction based on postcontrast venous and arterial differential T1 values: an error analysis.
Estimation of renal extraction fraction based on postcontrast venous and arterial differential T1 values: an error analysis.
复制标题
基于对比后静脉和动脉 T1 差值估计肾提取分数：误差分析。
DOI：
10.1002/mrm.20548
复制
发表时间：
2005
影响因子：
3.3
通讯作者：
Spielman,DanielM
中科院分区：
文献类型：
--
作者：
Levin,YakirS;Chow,LawrenceC;Pelc,NorbertJ;Sommer,FGraham;Spielman,DanielM
An error analysis for quantifying single kidney extraction fraction (EF) via differentialT1measurements in the renal vein (RV) and renal artery (RA) is presented. Sources of error include blood flow effects, the effect of a short repetition time (TR), and the impact of uncertainties in theT1estimates on the final EF calculations. Blood flow effects were investigated via simulation. For a range of blood velocities in the renal vein that may be found in kidney disease, incomplete refreshment of blood between readouts results in significant errors inT1estimation. For a .5‐cm slice, 110‐ms sampling interval, andT1of 600 ms,T1estimation to within 5% of trueT1requires an average through‐plane velocity of 6.75 cm/s for parabolic flow, and 3.5 cm/s for plug flow. Improvement can be achieved by accurately estimating the fraction of blood that has not refreshed between readouts (fold), while the quality of theT1estimate varies with the accuracy offoldestimation. Shortening of the TR was investigated using phantom and in vivo studies.T1was estimated to within 3% of the true value on phantoms, and within 5% of the true value for flowing blood for TR = 2T1. The estimated EF is shown to be very sensitive to the difference betweenT1RAandT1RV. To achieve 10% or 20% uncertainty in the EF estimate,T1in the renal vein and renal artery must be estimated to within approximately 1% or 2%. Because of limitations on measurement accuracy and precision, this method appears to be impractical at this time. Magn Reson Med 54:309–316, 2005. © 2005 Wiley‐Liss, Inc.
