Langaa Stine Sundgaard, Lauridsen Thomas Guldager, Mose Frank Holden, Fynbo Claire Anne, Theil Jørn, Bech Jesper Nørgaard
Gødstrup HospitalUniversity Clinic in Nephrology and Hypertension, Department of Medical Research, Gødstrup Hospital and Aarhus University, Lægaardvej 12J, 7500, Holstebro, Denmark.
Department of Nuclear Medicine, Gødstrup Hospital, Herning, Denmark.
EJNMMI Phys. 2021 May 31;8(1):43. doi: 10.1186/s40658-021-00389-0.
Changes in renal blood flow (RBF) may play a pathophysiological role in hypertension and kidney disease. However, RBF determination in humans has proven difficult. We aimed to confirm the feasibility of RBF estimation based on positron emission tomography/computed tomography (PET/CT) and rubidium-82 (Rb) using the abdominal aorta as input function in a 1-tissue compartment model.
Eighteen healthy subjects underwent two dynamic Rb PET/CT scans in two different fields of view (FOV). FOV-A included the left ventricular blood pool (LVBP), the abdominal aorta (AA) and the majority of the kidneys. FOV-B included AA and the kidneys in their entirety. In FOV-A, an input function was derived from LVBP and from AA, in FOV-B from AA. One-tissue compartmental modelling was performed using tissue time activity curves generated from volumes of interest (VOI) contouring the kidneys, where the renal clearance of Rb is represented by the K kinetic parameter. Total clearance for both kidneys was calculated by multiplying the K values with the volume of VOIs used for analysis. Intra-assay coefficients of variation and inter-observer variation were calculated.
For both kidneys, K values derived from AA did not differ significantly from values obtained from LVBP, neither were significant differences seen between AA in FOV-A and AA in FOV-B, nor between the right and left kidneys. For both kidneys, the intra-assay coefficients of variation were low (~ 5%) for both input functions. The measured K of 2.80 ml/min/cm translates to a total clearance for both kidneys of 766 ml/min/1.73 m.
Measurement of renal perfusion based on PET/CT and Rb using AA as input function in a 1-tissue compartment model is feasible in a single FOV. Based on previous studies showing Rb to be primarily present in plasma, the measured K clearance values are most likely representative of effective renal plasma flow (ERPF) rather than estimated RBF values, but as the accurate calculation of total clearance/flow is very much dependent on the analysed volume, a standardised definition for the employed renal volumes is needed to allow for proper comparison with standard ERPF and RBF reference methods.
肾血流量（RBF）的变化可能在高血压和肾脏疾病中发挥病理生理作用。然而，已证明在人体中测定RBF具有难度。我们旨在证实基于正电子发射断层扫描/计算机断层扫描（PET/CT）和82铷（Rb），以腹主动脉作为输入函数，在单组织隔室模型中估算RBF的可行性。
18名健康受试者在两个不同视野（FOV）下接受了两次动态Rb PET/CT扫描。FOV-A包括左心室血池（LVBP）、腹主动脉（AA）和大部分肾脏。FOV-B包括整个AA和双侧肾脏。在FOV-A中，输入函数分别从LVBP和AA得出，在FOV-B中从AA得出。使用勾勒肾脏轮廓的感兴趣区（VOI）生成的组织时间-活性曲线进行单组织隔室建模，其中Rb的肾脏清除率由动力学参数K表示。通过将K值与用于分析的VOI体积相乘来计算双侧肾脏的总清除率。计算批内变异系数和观察者间变异。
对于双侧肾脏，从AA得出的K值与从LVBP获得的值无显著差异，FOV-A中的AA与FOV-B中的AA之间、以及右肾和左肾之间也均未观察到显著差异。对于双侧肾脏，两种输入函数的批内变异系数均较低（约5%）。测得的K值为2.80 ml/min/cm，换算为双侧肾脏的总清除率为766 ml/min/1.73 m²。
在单视野下，基于PET/CT和Rb，以AA作为输入函数，在单组织隔室模型中测量肾脏灌注是可行的。基于先前显示Rb主要存在于血浆中的研究，测得的K清除率值很可能代表有效肾血浆流量（ERPF）而非估算的RBF值，但由于总清除率/流量的准确计算在很大程度上取决于所分析的体积，因此需要对所采用的肾脏体积进行标准化定义，以便与标准ERPF和RBF参考方法进行适当比较。
