Dana Nicholas, Di Biase Luigi, Natale Andrea, Emelianov Stanislav, Bouchard Richard
Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas; Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas.
Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas; Texas Cardiac Arrhythmia Institute, St. David's Medical Center, Austin, Texas; Department of Cardiology, University of Foggia, Foggia, Italy; Albert Einstein College of Medicine, Montefiore Hospital, New York, New York.
Heart Rhythm. 2014 Jan;11(1):150-7. doi: 10.1016/j.hrthm.2013.09.071. Epub 2013 Sep 27.
Radiofrequency (RF) ablation to treat atrial arrhythmia is limited by the inability to reliably assess lesion durability and transmurality.
The purpose of this study was to determine the feasibility of photoacoustic characterization of myocardial ablation lesions in vitro. In this study, we investigated the feasibility of combined ultrasound (US) and spectroscopic photoacoustic imaging to visualize RF ablation lesions in three dimensions (3D) based on unique differences in the optical absorption spectra between normal and ablated myocardial tissue.
Tissue samples were excised from the ventricles of fresh porcine hearts. Lesions were generated using an RF catheter ablation system using 20 to 30 W of power applied for 40 to 60 seconds. Ablated samples were imaged in the near-infrared regime (740-780 nm) using a combined PA/US imaging system. Measured PA spectra were correlated to the absorption spectra of deoxyhemoglobin and ablated tissue to produce a tissue characterization map (TCM) identifying 3D lesion location and extent. Tissue samples were stained and photographed for gross pathology. TCM and gross pathology images were coregistered to assess TCM accuracy.
TCM reliably characterized ablated and non-ablated tissue up to depths of 3 mm. TCM also assessed lesion position and extent with submillimeter accuracy in multiple dimensions. Segmented TCMs achieved >69% agreement with gross pathology.
The study results suggest that spectroscopic photoacoustic imaging has the potential to accurately assess RF ablation lesion size and position with submillimeter precision and may be well suited to guide transcatheter RF atrial ablation in clinical practice.
射频（RF）消融治疗房性心律失常受到无法可靠评估损伤耐久性和透壁性的限制。
本研究的目的是确定体外心肌消融损伤的光声表征的可行性。在本研究中，我们基于正常心肌组织和消融心肌组织光吸收光谱的独特差异，研究了联合超声（US）和光谱光声成像在三维（3D）可视化RF消融损伤的可行性。
从新鲜猪心脏的心室中切除组织样本。使用RF导管消融系统，以20至30瓦的功率施加40至60秒来产生损伤。使用联合PA/US成像系统在近红外区域（740-780nm）对消融样本进行成像。将测量的PA光谱与脱氧血红蛋白和消融组织的吸收光谱相关联，以生成组织表征图（TCM），确定3D损伤的位置和范围。对组织样本进行染色并拍照以进行大体病理学检查。将TCM和大体病理学图像进行配准以评估TCM的准确性。
TCM能够可靠地表征深度达3mm的消融和未消融组织。TCM还能在多个维度上以亚毫米精度评估损伤位置和范围。分割后的TCM与大体病理学的一致性>69%。
研究结果表明，光谱光声成像有潜力以亚毫米精度准确评估RF消融损伤的大小和位置，可能非常适合在临床实践中指导经导管RF心房消融。
