Department of Surgical Sciences/Nuclear Medicine & PET, Uppsala University, Uppsala, Sweden.
Centre for Research and Development, Uppsala/Gävleborg County, Gävle, Sweden.
J Nucl Cardiol. 2022 Jun;29(3):1119-1128. doi: 10.1007/s12350-020-02408-6. Epub 2020 Nov 4.
Quantification of myocardial blood flow (MBF) with PET requires accurate attenuation correction, which is performed using a separate CT. Misalignment between PET and CT scans has been reported to be a common problem. The purpose of the present study was to assess the effect of PET CT misalignment on the quantitative accuracy of cardiac O-water PET.
Ten clinical patients referred for evaluation of ischemia and assessment of MBF with O-water were included in the study. Eleven different misalignments between PET and CT were induced in 6 different directions with 10 and 20 mm amplitudes: caudal (+Z), cranial (- Z), lateral (±X), anterior (+Y), and anterior combined with cranial (+ Y and - Z). Blood flow was quantified from rates of washout (MBF) and uptake (transmural MBF, MBFt) for the whole left ventricle and the three coronary territories. The results from all misalignments were compared to the original scan without misalignment.
MBF was only minorly affected by misalignments, but larger effects were seen in MBFt. On the global level, average absolute deviation across all misalignments for MBF was 1.7% ± 1.4% and for MBFt 5.4% ± 3.2 Largest deviation for MBF was - 4.8% ± 5.8% (LCX, X + 20) and for MBFt - 19.3% ± 9.6% (LCX, X + 20). In general, larger effects were seen in LAD and LCX compared to in RCA.
The quantitative accuracy of MBF from O-water PET, based on the washout of the tracer, is only to a minor extent affected by misalignment between PET and CT.
正电子发射断层扫描（PET）心肌血流（MBF）的定量需要使用单独的 CT 进行准确的衰减校正。已经报道 PET 和 CT 扫描之间的配准不良是一个常见的问题。本研究的目的是评估 PET-CT 配准不良对 O-水 PET 心脏定量准确性的影响。
本研究纳入了 10 例临床患者，这些患者因评估缺血和评估 O-水的 MBF 而接受检查。在 6 个不同方向上诱导了 11 种不同的 PET 和 CT 配准偏差，幅度为 10 和 20mm：尾向（+Z）、头向（-Z）、侧方（±X）、前向（+Y）和前向联合头向（+Y 和-Z）。通过整个左心室和三个冠状动脉区域的洗脱率（MBF）和摄取率（透壁 MBF，MBFt）来定量血流。将所有配准的结果与未配准的原始扫描进行比较。
MBF 仅受到配准偏差的轻微影响，但在 MBFt 中观察到更大的影响。在整体水平上，所有配准偏差的 MBF 平均绝对偏差为 1.7%±1.4%，MBFt 为 5.4%±3.2%。MBF 的最大偏差为-4.8%±5.8%（LCX，X+20），MBFt 的最大偏差为-19.3%±9.6%（LCX，X+20）。总体而言，与 RCA 相比，LAD 和 LCX 中观察到的影响更大。
基于示踪剂洗脱的 O-水 PET 心肌血流的定量准确性仅受到 PET 和 CT 之间配准不良的轻微影响。
