Division of Pediatric Cardiology, Department of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, 3959 Broadway, New York, NY, 10032, USA.
GE Healthcare, ASL Europe, Munich, Germany.
Pediatr Radiol. 2020 May;50(5):656-663. doi: 10.1007/s00247-020-04623-2. Epub 2020 Feb 11.
The need for background error correction in phase-contrast flow analysis has historically posed a challenge in cardiac magnetic resonance (MR) imaging. While previous studies have shown that phantom correction improves flow measurements, it impedes scanner workflow.
To evaluate the efficacy of self-calibrated non-linear phase-contrast correction on flows in pediatric and congenital cardiac MR compared to phantom correction as the standard.
We retrospectively identified children who had great-vessel phase-contrast and static phantom sequences acquired between January 2015 and June 2015. We applied a novel correction method to each phase-contrast sequence post hoc. Uncorrected, non-linear, and phantom-corrected flows were compared using intraclass correlation. We used paired t-tests to compare how closely non-linear and uncorrected flows approximated phantom-corrected flows. In children without intra- or extracardiac shunts or significant semilunar valvular regurgitation, we used paired t-tests to compare how closely the uncorrected pulmonary-to-systemic flow ratio (Qp:Qs) and non-linear Qp:Qs approximated phantom-corrected Qp:Qs.
We included 211 diagnostic-quality phase-contrast sequences (93 aorta, 74 main pulmonary artery [MPA], 21 left pulmonary artery [LPA], 23 right pulmonary artery [RPA]) from 108 children (median age 15 years, interquartile range 11-18 years). Intraclass correlation showed strong agreement between non-linear and phantom-corrected flow measurements but also between uncorrected and phantom-corrected flow measurements. Non-linear flow measurements did not more closely approximate phantom-corrected measurements than did uncorrected measurements for any vessel. In 39 children without significant shunting or regurgitation, mean non-linear Qp:Qs (1.07; 95% confidence interval [CI] = 1.01, 1.13) was no closer than mean uncorrected Qp:Qs (1.06; 95% CI = 1.00, 1.13) to mean phantom-corrected Qp:Qs (1.02; 95% CI = 0.98, 1.06).
Despite strong agreement between self-calibrated non-linear and phantom correction, cardiac flows and shunt calculations with non-linear correction were no closer to phantom-corrected measurements than those without background correction. However, phantom-corrected flows also demonstrated minimal differences from uncorrected flows. These findings suggest that in the current era, more accurate phase-contrast flow measurements might limit the need for background correction. Further investigation of the clinical impact and optimal methods of background correction in the pediatric and congenital cardiac population is needed.
在心脏磁共振成像中，相位对比流动分析需要进行背景误差校正，这在历史上一直是一个挑战。虽然之前的研究表明，相位对比流动分析中的相位对比流动分析可以改善流动测量，但它会阻碍扫描仪的工作流程。
与标准的相位对比校正相比，评估自校准非线性相位对比校正对儿科和先天性心脏病磁共振成像中流动的疗效。
我们回顾性地确定了 2015 年 1 月至 2015 年 6 月期间接受大血管相位对比和静态体模序列采集的儿童。我们对每个相位对比序列进行了事后的新型校正方法。使用组内相关比较未校正、非线性和相位对比校正的流量。使用配对 t 检验比较非线性和未校正流量如何更接近相位对比校正流量。在没有心内或心外分流或明显半月瓣反流的儿童中，我们使用配对 t 检验比较未校正的肺至体循环流量比（Qp：Qs）和非线性 Qp：Qs 如何更接近相位对比校正的 Qp：Qs。
我们纳入了 108 例儿童（中位数年龄 15 岁，四分位间距 11-18 岁）211 个诊断质量的相位对比序列（93 例主动脉，74 例主肺动脉[MPA]，21 例左肺动脉[LPA]，23 例右肺动脉[RPA]）。组内相关显示，非线性和相位对比校正的流量测量之间具有很强的一致性，但未校正和相位对比校正的流量测量之间也具有很强的一致性。对于任何血管，非线性流量测量都没有比未校正的测量更接近相位对比校正的测量。在 39 例无明显分流或反流的儿童中，平均非线性 Qp：Qs（1.07；95%置信区间[CI] = 1.01，1.13）与平均未校正 Qp：Qs（1.06；95% CI = 1.00，1.13）的平均值相比，Qp：Qs 与平均相位对比校正 Qp：Qs（1.02；95% CI = 0.98，1.06）没有更近。
尽管自校准非线性和相位对比校正之间具有很强的一致性，但与非线性校正相关的心脏流量和分流计算与相位对比校正测量值的一致性不如没有背景校正的测量值。然而，相位对比校正的流量与未校正的流量相比也显示出最小的差异。这些发现表明，在当前时代，更准确的相位对比流动测量可能会限制对背景校正的需求。需要进一步研究在儿科和先天性心脏人群中背景校正的临床影响和最佳方法。
