Phipps Jennifer E, Hoyt Taylor, Vela Deborah, Wang Tianyi, Michalek Joel E, Buja L Maximilian, Jang Ik-Kyung, Milner Thomas E, Feldman Marc D
From the Department of Medicine (J.E.P., T.H., M.D.F.) and Epidemiology and Biostatistics (J.E.M.), University of Texas Health Science Center San Antonio; Department of Cardiovascular Pathology, Texas Heart Institute, Houston (D.V., L.M.B.); Department of Biomedical Engineering, University of Texas at Austin (T.W., T.E.M.); Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston (I.-K.J.); and Department of Veterans Affairs, South Texas Veterans Health Care System, San Antonio (M.D.F.).
Circ Cardiovasc Interv. 2016 Jul;9(7). doi: 10.1161/CIRCINTERVENTIONS.115.003163.
Intravascular optical coherence tomography (IVOCT) images are recorded by detecting light backscattered within coronary arteries. We hypothesize that non-thin-capped fibroatheroma (TCFA) causes may scatter light to create the false appearance of IVOCT TCFA.
Ten human cadaver hearts were imaged with IVOCT (n=14 coronary arteries). IVOCT and histological TCFA images were coregistered and compared. Of 21 IVOCT TCFAs (fibrous cap <65 μm, lipid arc >1 quadrant), only 8 were true histological TCFA. Foam cell infiltration was responsible for 70% of false IVOCT TCFA and caused both thick-capped fibroatheromas to appear as TCFA, and the appearance of TCFAs when no lipid core was present. Other false IVOCT TCFA causes included smooth muscle cell-rich fibrous tissue (12%) and loose connective tissue (9%). If the lipid arc >1 quadrant (obtuse) criterion was disregarded, 45 IVOCT TCFAs were identified, and sensitivity of IVOCT TCFA detection increased from 63% to 87%, and specificity remained high at 92%.
We demonstrate that IVOCT can exhibit 87% (95% CI, 75%-93%) sensitivity and 92% specificity (95% CI, 86%-96%) to detect all lipid arcs (both obtuse and acute, <1 quadrant) TCFA, and we also propose new mechanisms involving light scattering that explain why other plaque components can masquerade as TCFA and cause low positive predictive value of IVOCT for TCFA detection (47% for obtuse lipid arcs). Disregarding the lipid arc >1 quadrant requirement enhances the ability of IVOCT to detect TCFA.
血管内光学相干断层扫描（IVOCT）图像是通过检测冠状动脉内背向散射光来记录的。我们假设非薄帽纤维粥样斑块（TCFA）的病因可能会散射光线，从而产生IVOCT检测到的TCFA的假象。
对10个人类尸体心脏进行IVOCT成像（n = 14条冠状动脉）。将IVOCT和组织学TCFA图像进行配准并比较。在21个IVOCT检测到的TCFA（纤维帽<65μm，脂质弧>1个象限）中，只有8个是真正的组织学TCFA。泡沫细胞浸润导致70%的假IVOCT TCFA，使厚帽纤维粥样斑块也表现为TCFA，并且在没有脂质核心时也出现TCFA的假象。其他导致假IVOCT TCFA的原因包括富含平滑肌细胞的纤维组织（12%）和疏松结缔组织（9%）。如果不考虑脂质弧>1个象限（钝角）的标准，则识别出45个IVOCT检测到的TCFA，IVOCT检测TCFA的敏感性从63%提高到87%，特异性仍高达92%。
我们证明IVOCT检测所有脂质弧（钝角和锐角，<1个象限）的TCFA时，敏感性为87%（95%CI，75%-93%），特异性为92%（95%CI，86%-96%），并且我们还提出了涉及光散射的新机制，解释了为什么其他斑块成分可以伪装成TCFA，并导致IVOCT检测TCFA的阳性预测值较低（钝角脂质弧为47%）。不考虑脂质弧>1个象限的要求可增强IVOCT检测TCFA的能力。
