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.

We analyzed optical coherence tomographic (OCT) characteristics of different types of coronary thrombi that had been confirmed at postmortem histologic examination. We examined 108 coronary arterial segments of 40 consecutive human cadavers. OCT images of red and white thrombi were obtained and the intensity property of these thrombi was analyzed. Red and white thrombi were found in 16 (17%) and 19 (18%) of the 108 arterial segments, respectively. Red thrombi were identified as high-backscattering protrusions inside the lumen of the artery, with signal-free shadowing in the OCT image. White thrombi were identified as low-backscattering projections in the OCT image. There were no significant differences in peak intensity of OCT signal between red and white thrombi (130+/-18 vs 145+/-34, p=0.12). However, the 1/2 attenuation width of the signal intensity curve, which was defined as the distance from peak intensity to its 1/2 intensity, was significantly different between red and white thrombi (324+/-50 vs 183+/- 42 microm, p<0.0001). A cut-off value of 250 microm in the 1/2 width of signal intensity attenuation can differentiate white from red thrombi with a sensitivity of 90% and specificity of 88%. We present the first detailed description of the characteristics of different types of coronary thrombi in OCT images. Optical coherence tomography may allow us not only to estimate plaque morphology but also to distinguish red from white thrombi.

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akotsubo-like left ventricular (LV) dysfunction ischaracterized by a unique morphologic feature on left ventriculography (LVG) and some clinical features, including a predominance in elderly women, as well as a favorable prognosis. [1][2][3][4][5][6][7][8][9] The LV wall motion abnormality is quite different from that in myocardial infarction; it occurs in the LV apical region (LV apical ballooning), but improves within several weeks. The precise mechanism remains still unclear. Kurisu et al reported that coronary microcirculation, assessed by thrombolysis in myocardial infarction trial frame count, is impaired in patients with takotsubo-like LV dysfunction. 4 And Nishikawa et al reported that coronary microvascular function assessed by 99m Tc-tetrofosmin myocardial single photon emission computed tomography is impaired in patients with takotsubo-like LV dysfunction. 6 It has been also reported that the coronary flow velocity (CFV) pattern and CFV reserve (CFVR), measured with a Doppler guidewire, reflect the degree of coronary microvascular dysfunction under stable hemodynamic conditions in the absence of epicardial coronary stenosis, 10-14 so the aim of the present study was to evaluate coronary microcirculation in patients with takotsubo-like LV dysfunction by analyzing CFV pattern and CFVR in the acute phase and 3 weeks later. Methods Study PatientsWe studied 8 consecutive patients with takotsubo-like LV dysfunction (7 females, 1 male). All patients were diagnosed with takotsubo-like LV dysfunction according to the following criteria: (1) LV wall motion abnormality mainly at the apex on LVG; (2) ST-segment elevation or T-wave abnormality in at least 2 contiguous electrocardiogram (ECG) leads; (3) no history of prior myocardial infarction; and (4) normal coronary angiography (CAG) (luminal narrowing of <25% in all 3 coronary arteries). We excluded patients with subarachnoid hemorrhage, pheochromocytoma crisis, atrial fibrillation, hypertrophic cardiomyopathy, severe valvular heart disease and post-tachycardia condition. The existence of hypertension, hyperlipidemia, diabetes mellitus, and smoking were determined, using the following criteria: hypertension was defined as blood pressure >140/90 mmHg or current medication; hyperlipidemia was defined as total cholesterol concentration >220 mg/dl, triglyceride concentration >150 mg/dl or current medication; diabetes mellitus was defined as fasting plasma glucose concentration >120 mg/dl, plasma glucose concentration (anytime) >200 mg/dl or current medication. Within 24 h of symptom onset, LVG and CAG were performed by the femoral approach after intravenous infusion of 5,000 U of heparin. LV end-diastolic pressure (LVEDP) was obtained before LVG. After confirming the LV apical wall motion abnormality and normal CAG, the phasic CFV spectrum was recorded at rest and during hyperemia induced by an intravenous injection of 0.15 mg·kg -1 ·min -1 adenosine 5'-triphosphate, in the middle portion of the left anterior descending coronary artery (LAD), the left circumflex ar...