Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies

Objectives: The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease. Background: Intravascular optical coherence tomography (IVOCT) is a catheter-based modality that acquires images at a resolution of ∼10 μm, enabling visualization of blood vessel wall microstructure in vivo at an unprecedented level of detail. IVOCT devices are now commercially available worldwide, there is an active user base, and the interest in using this technology is growing. Incorporation of IVOCT in research and daily clinical practice can be facilitated by the development of uniform terminology and consensus-based standards on use of the technology, interpretation of the images, and reporting of IVOCT results. Methods: The IWG-IVOCT, comprising more than 260 academic and industry members from Asia, Europe, and the United States, formed in 2008 and convened on the topic of IVOCT standardization through a series of 9 national and international meetings. Results: Knowledge and recommendations from this group on key areas within the IVOCT field were assembled to generate this consensus document, authored by the Writing Committee, composed of academicians who have participated in meetings and/or writing of the text. Conclusions: This document may be broadly used as a standard reference regarding the current state of the IVOCT imaging modality, intended for researchers and clinicians who use IVOCT and analyze IVOCT data

Quantification of coronary microvascular resistance using angiographic images for volumetric blood flow measurement: in vivo validation

Structural coronary microcirculation abnormalities are important prognostic determinants in clinical settings. However, an assessment of microvascular resistance (MR) requires a velocity wire. A first-pass distribution analysis technique to measure volumetric blood flow has been previously validated. The aim of this study was the in vivo validation of the MR measurement technique using first-pass distribution analysis. Twelve anesthetized swine were instrumented with a transit-time ultrasound flow probe on the proximal segment of the left anterior descending coronary artery (LAD). Microspheres were injected into the LAD to create a model of microvascular dysfunction. Adenosine (400 μg·kg−1·min−1) was used to produce maximum hyperemia. A region of interest in the LAD arterial bed was drawn to generate time-density curves using angiographic images. Volumetric blood flow measurements (Qa) were made using a time-density curve and the assumption that blood was momentarily replaced with contrast agent during the injection. Blood flow from the flow probe (Qp), coronary pressure (Pa), and right atrium pressure (Pv) were continuously recorded. Flow probe-based normalized MR (NMRp) and angiography-based normalized MR (NMRa) were calculated using Qp and Qa, respectively. In 258 measurements, Qa showed a strong correlation with the gold standard Qp (Qa = 0.90 Qp + 6.6 ml/min, r2 = 0.91, P < 0.0001). NMRa correlated linearly with NMRp (NMRa = 0.90 NMRp + 0.02 mmHg·ml−1·min−1, r2 = 0.91, P < 0.0001). Additionally, the Bland-Altman analysis showed a close agreement between NMRa and NMRp. In conclusion, a technique based on angiographic image data for quantifying NMR was validated using a swine model. This study provides a method to measure NMR without using a velocity wire, which can potentially be used to evaluate microvascular conditions during coronary arteriography

Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies: a report from the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation

The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease