Suter Melissa J, Kashiwagi Manabu, Gallagher Kevin A, Nadkarni Seemantini K, Asanani Nayan, Tanaka Atsushi, Conditt Gerard B, Tellez Armando, Milewski Krzysztof, Kaluza Greg L, Granada Juan F, Bouma Brett E, Tearney Guillermo J
Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,
Int J Cardiovasc Imaging. 2015 Aug;31(6):1097-106. doi: 10.1007/s10554-015-0668-0. Epub 2015 Apr 29.
Intracoronary optical frequency domain imaging (OFDI), requires the displacement of blood for clear visualization of the artery wall. Radiographic contrast agents are highly effective at displacing blood however, may increase the risk of contrast-induced nephropathy. Flushing media viscosity, flow rate, and flush duration influence the efficiency of blood displacement necessary for obtaining diagnostic quality OFDI images. The aim of this work was to determine the optimal flushing parameters necessary to reliably perform intracoronary OFDI while reducing the volume of administered radiographic contrast, and assess the influence of flushing media choice on vessel wall measurements. 144 OFDI pullbacks were acquired together with synchronized EKG and intracoronary pressure wire recordings in three swine. OFDI images were graded on diagnostic quality and quantitative comparisons of flushing efficiency and intracoronary cross-sectional area with and without precise refractive index calibration were performed. Flushing media with higher viscosities resulted in rapid and efficient blood displacement. Media with lower viscosities resulted in increased blood-media transition zones, reducing the pullback length of diagnostic quality images obtained. Flushing efficiency was found to increase with increases in flow rate and duration. Calculations of lumen area using different flushing media were significantly different, varying up to 23% (p < 0.0001). This error was eliminated with careful refractive index calibration. Flushing media viscosity, flow rate, and flush duration influence the efficiency of blood displacement necessary for obtaining diagnostic quality OFDI images. For patients with sensitivity to contrast, to reduce the risk of contrast induced nephrotoxicity we recommend that intracoronary OFDI be conducted with flushing solutions containing little or no radiographic contrast. In addition, our findings show that careful refractive index compensation should be performed, taking into account the specific contrast agent used, in order to obtain accurate intravascular OFDI measurements.
冠状动脉内光学频域成像（OFDI）需要置换血液以清晰显示动脉壁。放射造影剂在置换血液方面非常有效，然而，可能会增加造影剂诱发肾病的风险。冲洗介质的粘度、流速和冲洗持续时间会影响获得诊断质量的OFDI图像所需的血液置换效率。这项工作的目的是确定在减少放射造影剂用量的同时可靠地进行冠状动脉内OFDI所需的最佳冲洗参数，并评估冲洗介质选择对血管壁测量的影响。在三只猪身上采集了144次OFDI回撤，并同步记录心电图和冠状动脉内压力导丝。对OFDI图像的诊断质量进行分级，并对有无精确折射率校准的冲洗效率和冠状动脉横截面积进行定量比较。粘度较高的冲洗介质可导致快速有效的血液置换。粘度较低的介质会导致血液-介质过渡区增加，从而缩短获得的诊断质量图像的回撤长度。发现冲洗效率随流速和持续时间的增加而提高。使用不同冲洗介质计算的管腔面积有显著差异，相差高达23%（p<0.0001）。通过仔细的折射率校准消除了这种误差。冲洗介质的粘度、流速和冲洗持续时间会影响获得诊断质量的OFDI图像所需的血液置换效率。对于对造影剂敏感的患者，为降低造影剂诱发肾毒性的风险，我们建议使用含少量或不含放射造影剂的冲洗溶液进行冠状动脉内OFDI。此外，我们的研究结果表明，为了获得准确的血管内OFDI测量值，并考虑到所使用的特定造影剂进行仔细的折射率补偿。
