背景:在体内检测冠状动脉易损斑块并评估其脆弱性一直是临床医生和研究界面临的巨大挑战。血管内超声(IVUS)在临床实践中通常用于诊断和治疗决策。然而,由于IVUS有限的分辨率(约150-200µm),仅检测阈值帽厚度为65µm的易损斑块是不够的。光学相干断层扫描(OCT)的分辨率为15-20µm,可以更准确地测量纤维帽厚度。本研究的目的是使用OCT作为基准,以获得患者特定的冠状动脉斑块帽厚度,并评估OCT和IVUS纤维帽定量之间的差异。还引入了具有整数值0-4的帽指数作为斑块易损性的定量度量,以研究斑块易损性。
方法:数据来自10例接受IVUS的冠心病患者(平均年龄:70.4;m:6;f:4),OCT,在获得知情同意的情况下,在心血管研究基金会(CRF)使用批准的方案收集血管造影.选择具有脂质核心和纤维帽的348个切片用于研究。基于卷积神经网络(CNN)和基于专家的数据分割是使用先前发布的已建立的方法进行的。提取帽厚度数据以量化IVUS和OCT测量之间的差异。
结果:对于分析的348个切片,OCT和IVUS帽厚度测量的平均值差异为1.83%(p=0.031).然而,点对点差异的平均值为35.76%.比较每个板的最小盖厚度,20个斑块IVUS-OCT差异的平均值为44.46%,范围从2.36%到91.15%。对于分配给348个切片的cap索引值,OCT和IVUS分配的差异为25%.然而,对于OCT帽指数=2和3组,分歧率为91%和80%,分别。此外,从基线到随访的cap指数变化观察表明,IVUS结果与OCT相比有80%的差异.
结论:这些初步结果表明IVUS和OCT斑块盖厚度测量之间存在显著差异。需要大规模的患者研究来证实我们的发现。
BACKGROUND: Detecting coronary vulnerable plaques in vivo and assessing their vulnerability have been great challenges for clinicians and the research community. Intravascular ultrasound (IVUS) is commonly used in clinical practice for diagnosis and treatment decisions. However, due to IVUS limited resolution (about 150-200 µm), it is not sufficient to detect vulnerable plaques with a threshold cap thickness of 65 µm. Optical Coherence Tomography (OCT) has a resolution of 15-20 µm and can measure fibrous cap thickness more accurately. The aim of this study was to use OCT as the benchmark to obtain patient-specific coronary plaque cap thickness and evaluate the differences between OCT and IVUS fibrous cap quantifications. A cap index with integer values 0-4 was also introduced as a quantitative measure of plaque vulnerability to study plaque vulnerability.
METHODS: Data from 10 patients (mean age: 70.4; m: 6; f: 4) with coronary heart disease who underwent IVUS, OCT, and angiography were collected at Cardiovascular Research Foundation (CRF) using approved protocol with informed consent obtained. 348 slices with lipid core and fibrous caps were selected for study. Convolutional Neural Network (CNN)-based and expert-based data segmentation were performed using established methods previously published. Cap thickness data were extracted to quantify differences between IVUS and OCT measurements.
RESULTS: For the 348 slices analyzed, the mean value difference between OCT and IVUS cap thickness measurements was 1.83% (p = 0.031). However, mean value of point-to-point differences was 35.76%. Comparing minimum cap thickness for each plaque, the mean value of the 20 plaque IVUS-OCT differences was 44.46%, ranging from 2.36% to 91.15%. For cap index values assigned to the 348 slices, the disagreement between OCT and IVUS assignments was 25%. However, for the OCT cap index = 2 and 3 groups, the disagreement rates were 91% and 80%, respectively. Furthermore, the observation of cap index changes from baseline to follow-up indicated that IVUS results differed from OCT by 80%.
CONCLUSIONS: These preliminary results demonstrated that there were significant differences between IVUS and OCT plaque cap thickness measurements. Large-scale patient studies are needed to confirm our findings.