Optical Coherence Tomography of the Coronary Arteries

Intravascular imaging, particularly optical coherence tomography, has brought significant improvement in diagnostic and therapeutical approaches to coronary artery disease and has offered superior high-resolution visualization of coronary arteries. The ability to obtain images of intramural and transmural coronary structures allows the study of the process of atherosclerosis, effect of therapies, mechanism of acute coronary syndrome and stent failure, and performance of new devices and enables the interventional cardiologist to optimize the effect of percutaneous coronary intervention. In this review, we provide the summary of the latest published data on clinical use of optical coherence tomography as well as practical algorithm for optical coherence tomography-guided percutaneous coronary intervention for daily interventional practice.     

Optical coherence tomography. Initial experience in patients undergoing percutaneous coronary intervention

Optical coherence tomography is a new intracoronary diagnostic technique that has a higher resolution than other techniques, such as intravascular ultrasound. We used optical coherence tomography to study outcomes after stent implantation in six patients who had undergone percutaneous coronary intervention, and in whom angiography showed normal results after revascularization. Material was observed to protrude through the stent struts in all patients, small dissections were seen at the stent edges in four patients, and there was incomplete stent apposition in four patients. In two patients, small amounts of thrombus were observed to form around the tomography catheter. With optical coherence tomography, it was possible to detect areas in which the results of percutaneous coronary intervention were suboptimal, despite a satisfactory appearance on angiography.     

What is the role of accreditation in the era of competency-based specialist training - A perspective from the United Kingdom

Optical coherence tomography is an exciting light-based imaging modality with a much higher axial resolution as compared with intravascular ultrasound. The diagnostic value of optical coherence tomography resides in its ability to provide information on the stent interaction with the vessel wall at the level of individual struts. Chief clinical implications include evaluating strut neointimal coverage and strut malapposition following coronary stenting. This Editorial covers the basics of optical coherence tomography, its established and potential clinical implications, probable caveats and downsides, in addition to a future perspective, all in view of the late-breaking peer-reviewed literature.     

Criteria for the diagnosis of dysplasia by endoscopic optical coherence tomography

BACKGROUND: Endoscopic optical coherence tomography provides images of the GI mucosa and submucosa in microscopic detail. It is unknown whether endoscopic optical coherence tomography can reliably detect dysplasia. Colon polyps were used as a model to determine whether dysplasia in GI tissue has characteristic optical coherence tomography imaging features. METHODS: Endoscopic optical coherence tomography images of colon polyps and normal colon tissue were obtained at colonoscopy. In real time, endoscopists compared tissue organization and light scattering for polyps and normal mucosa with endoscopic optical coherence tomography. Imaged polyps were removed and evaluated histopathologically. Organization and light scattering, as assessed by endoscopic optical coherence tomography at colonoscopy, were compared for adenomas versus hyperplastic polyps. A computer program also quantified and compared the degree of light scattering for hyperplastic polyps and adenomas. RESULTS: A total of 44 polyps were imaged in 24 patients (30 adenomas, 14 hyperplastic polyps). Endoscopic optical coherence tomography images of adenomas had significantly less structure (p = 0.0005) and scattered light to a lesser degree than hyperplastic polyps (p = 0.0007). Hyperplastic polyps were significantly closer in organization (p = 0.0003) and light scattering (p = 0.0006) to normal mucosa as compared with adenomas. By digital image analysis, the light-scattering property of hyperplastic polyps was closer to normal mucosa compared with adenomas (14.86 vs. 45.81; p = 0.0001). CONCLUSIONS: Real-time endoscopic optical coherence tomography imaging differentiated adenomas, hyperplastic polyps, and normal colon tissue. By using the colon adenoma as a model, the endoscopic optical coherence tomography characteristics of dysplasia are loss of tissue organization and reduced light scattering.     

Optical coherence tomography findings during "evolving" stent thrombosis

Stent thrombosis is a rare but feared complication. While intravascular ultrasound and optical coherence tomography are frequently used to unravel mechanical predisposing factors in patients suffering from this dreadful complication, no information exists on the early pathophysiology of stent thrombosis before coronary flow has been interrupted. We present a case where optical coherence tomography was used to gain novel insights into the earliest stages of stent thrombosis. In our patient with a possible "evolving" stent thrombosis, optical coherence tomography revealed a unique "spider web-like" or "cheese-like" thrombus morphology not previously reported.     

Optical coherence tomography compared with histology of the main pancreatic duct structure in normal and pathological conditions: An ‘ex vivo study’

BACKGROUND AND STUDY AIMS: Optical coherence tomography permits high-resolution imaging of tissue microstructures by a probe inserted into the main pancreatic duct through a standard ERCP catheter. The aim of this study was to compare optical coherence tomography images of the main pancreatic duct with histology and identify the optical coherence tomography pattern of the normal and pathological structure of the main pancreatic duct. PATIENTS AND METHODS: Multiple sections of neoplastic and non-neoplastic segments of 10 consecutive surgical pancreatic specimens obtained from patients with pancreatic head adenocarcinoma were investigated by optical coherence tomography scanning within 1h of resection. One hundred optical coherence tomography findings were then compared with the corresponding histopathological diagnoses. RESULTS: Main pancreatic duct wall architecture appeared at optical coherence tomography investigation as a three-layer structure with a different back-scattered signal from each layer. Optical coherence tomography imaging was concordant with histology in 81.8% and 18.75% of sections with normal tissue and chronic inflammatory changes. The K statistic between the two procedures was equal to 0.059 for non-neoplastic main pancreatic duct wall appearance. In all neoplastic sections optical coherence tomography showed a subverted layer architecture with heterogeneous back-scattering of the signal and was concordant with histology. CONCLUSIONS: Optical coherence tomography provided images of main pancreatic duct wall structure that were concordant with histology in 100% of cases in presence of neoplastic ductal changes and did not have false-positive or negative results. Optical coherence tomography images were also concordant with histology in about 80% of cases with normal main pancreatic duct structure; however, the differential diagnosis between normal tissue and chronic pancreatitis or dysplastic changes appeared very difficult.     

Visualization of subsurface blood vessels by color Doppler optical coherence tomography in rats: before and after hemostatic therapy.

BACKGROUND: The ability to visualize subsurface blood vessels and measure flow may be useful in certain experimental and clinical settings. METHODS: Color Doppler optical coherence tomography was used to visualize and measure blood flow in subsurface vessels in vivo in a rat skin flap model. Local "hemostatic" interventions (epinephrine or sclerosant injection, heat probe, and laser) were then applied and imaging was repeated. The skin flap was evaluated histologically. RESULTS: Subsurface blood vessels were easily visualized in cross-section, and vessel diameter and bidirectional blood flow velocity were readily measured. Color Doppler optical coherence tomography demonstrated that flow was significantly reduced after epinephrine injection and became undetectable after the other interventions. This correlated with pathologic evidence of vessel damage in all interventions, except for epinephrine injection. Although vessel response was as predicted to most interventions, the response to epinephrine was only temporary, and limited application of heat alone from the heat probe halted flow without visually apparent surface injury. CONCLUSIONS: Color Doppler optical coherence tomography provides high-resolution, cross-sectional flow imaging in subsurface blood vessels. Color Doppler optical coherence tomography is potentially a better technique for the study of existing and new hemostatic intervention in the laboratory. Potential future clinical applications include monitoring of the response to hemostatic modalities.     

Feasibility of use of magnesium reabsorbable scaffolds in complex coronary artery disease: True bifurcation,multiple overlapping scaffolds and chronic total occlusion treatment

We present first-in-human treatment with bioabsorbable magnesium scaffolds for percutaneous coronary intervention in a patient with nickel allergy. We present images from angiography and optical coherence tomography at three months. We also review the current status of these novel devices.     

Diagnostic accuracy of optical coherence tomography and intravascular ultrasound for the detection and characterization of atherosclerotic plaque composition in ex-vivo coronary specimens: a comparison with histology

BACKGROUND: Both intravascular ultrasound and optical coherence tomography have been purported to accurately detect and characterize coronary atherosclerotic plaque composition. The aim of our study was to directly compare the reproducibility and diagnostic accuracy of optical coherence tomography and intravascular ultrasound for the detection and characterization of coronary plaque composition ex vivo as compared with histology. METHODS AND RESULTS: Intravascular ultrasound (20 MHz) and optical coherence tomography imaging was performed in eight heart specimens using motorized pullback. Standard histology using hematoxylin-eosin and van Gieson staining was performed on 4 mum thick slices. Each slice was divided into quadrants and accurately matched cross-sections were analyzed for the presence of fibrous, lipid-rich, and calcified coronary plaque using standard definitions for both intravascular ultrasound and optical coherence tomography and correlated with histology. After exclusion of 145/468 quadrants, we analyzed the remaining 323 quadrants with excellent image quality in each procedure. Optical coherence tomography demonstrated a sensitivity and specificity of 91/88% for normal wall, 64/88% for fibrous plaque, 77/94% for lipid-rich plaque, and 67/97% for calcified plaque as compared with histology. Intravascular ultrasound demonstrated a sensitivity and specificity of 55/79% for normal wall, 63/59% for fibrous plaque, 10/96% for lipid-rich plaque, and 76/98% for calcified plaque. Both intravascular ultrasound and optical coherence tomography demonstrated excellent intraobserver and interobserver agreement (optical coherence tomography: kappa=0.90, kappa=0.82; intravascular ultrasound: kappa=0.87, kappa=0.86). CONCLUSION: Optical coherence tomography is superior to intravascular ultrasound for the detection and characterization of coronary atherosclerotic plaque composition, specifically for the differentiation of noncalcified, lipid-rich, or fibrous plaque.     

Main pancreatic duct, common bile duct and sphincter of Oddi structure visualized by optical coherence tomography: An ex vivo study compared with histology

BACKGROUND: Optical coherence tomography has been proposed to obtain high-resolution imaging of tissue structure of GI tract. Up till now, the optical coherence tomography appearance of the common bile duct, main pancreatic duct and sphincter of Oddi wall structure has not yet been defined. AIMS: To compare, in a prospective study, optical coherence tomography images of pancreato-biliary ductal system with histology and identify the optical coherence tomography pattern of the normal wall structure of the ducts. METHODS: Multiple sections of non-neoplastic segments of five consecutive ex vivo human pancreatic specimens were investigated by optical coherence tomography scanning within 1h of resection. Sixty optical coherence tomography images were compared with the corresponding histological findings. RESULTS: Optical coherence tomography appearance of normal common bile duct, main pancreatic duct and sphincter of Oddi is characterized by a differentiated three-layer architecture with a regular surface and a homogeneous back-scattered signal, corresponding to the single layer of epithelial cells, the connective-muscular layer and the muscular or acinar structure, respectively. Optical coherence tomography and histology findings were concordant in all cases. CONCLUSIONS: Optical coherence tomography was able to provide in real-time images of wall structure of the normal common bile duct, main pancreatic duct and sphincter of Oddi that are similar to those obtained by histology. These results suggest that optical coherence tomography could enable high-resolution images to be obtained from the pancreato-biliary system during an ERCP procedure.     

Optical coherence tomography following percutaneous coronary intervention with Excimer laser coronary atherectomy

The indications for Excimer laser coronary atherectomy (ELCA) have been refined in modern interventional practice. With the expanding role for optical coherence tomography (OCT) providing high-resolution intra-coronary imaging, this article examines the appearance of the coronary lumen after ELCA. Each indication for ELCA is discussed and illustrated with a clinical case, followed by detailed analysis of the OCT imaging pre and post ELCA. The aim of the article is to provide information to interventional cardiologists to facilitate decision making during PCI, when ELCA has been used as part of the interventional strategy.     

Assessing atherothrombotic burden with optical coherence tomography analysis may facilitate post‐PCI prognostication and antiplatelet therapy

• Atherothrombotic burden (ATB) correlates with myocardial blush grade (MBG), a known predictor of mortality and outcome after ST‐elevation myocardial infarction.
• Quantitative or semiquantitative analysis of ATB with optical coherence tomography may assist interventional cardiologists in post‐PCI prognostication and , perhaps, in rendering more aggressive antiplatelet therapy.
• Future studies comparing treatment strategies for post‐PCI patients with elevated ATB or depressed MBG may identify best practices after acute coronary syndromes.

     

Optical Coherence Tomography in Inflammatory Bowel Disease: Prospective Evaluation of 35 Patients

Purpose  Optical coherence tomography is a technique using infrared light in tissues of the gastrointestinal tract and human colon affected by inflammatory diseases. We evaluated whether there are specific patterns of optical coherence tomography for inflammatory bowel disease and compared the technique performance to the histology. Methods  Optical coherence tomography was performed in 35 patients (18 men; 31 ulcerative colitis, 4 Crohn’s disease). The images were obtained from affected and normal colon at endoscopy. Two biopsies of the sites visualized were taken. Two endoscopists scored the images, and two pathologists, blind to the endoscopy and optical coherence tomography, performed the histologic evaluation. Results  Three optical coherence tomography patterns were identified: 1) mucosal backscattering alteration, 2) delimited dark areas, and 3) layered colonic wall. Compared with the histology, mucosal backscattering alteration was the most effective in recognizing the disease in patients (P = 0.007 in colon segments affected, and P < 0.001 in normal segments). The sensitivity and specificity have been 100 and 78 percent, respectively. Conclusions  The in vivo optical coherence tomography correctly detected inflammatory bowel disease features in affected and apparently normal colon, and allowed to discriminate patterns for active ulcerative colitis and Crohn’s disease.     

2011心血管影像回眸

基于影像学证据的诊断、治疗与干预措施越来越受到临床的重视。现以2011年国际发表的文献为基础,概述该年度在心血管影像领域包括超声心动图、核医学、磁共振成像、计算机断层成像、血管内超声及光学相干成像技术的最新进展与研究热点。     

Optical coherence tomography in pediatric patients: A feasible technique for diagnosing celiac disease in children with villous atrophy

Background and aimCeliac disease is a common condition with many atypical manifestations, where histology serves as the “gold standard” for diagnosis. A useful new technique, optical coherence tomography, can depict villous morphology in detail, using light waves. This study examined the correlation between the sensitivity and specificity of optical coherence tomography in pediatric patients undergoing esophago-gastro-duodenoscopy for the diagnosis of celiac disease.Materials and methodsA total of 134 children were prospectively enrolled, 67 with a serological suspicion of celiac disease (group 1) and 67 with negative histology for celiac disease (group 2). During a diagnostic esophago-gastro-duodenoscopy we acquired multiple images and films in the four quadrants of the second part of the duodenum, and biopsies were taken in the area where optical coherence tomography had been done. Three patterns of villous morphology were considered: pattern 1 = no atrophy (types 0, 1 or 2 of the Marsh classification); pattern 2 = mild atrophy (type 3a or 3b); pattern 3 = marked atrophy (type 3c).ResultsThe diagnosis of celiac disease was histologically confirmed in all 67 children with positive antiendomysium and/or antitransglutaminase antibodies. Optical coherence tomography correlated with pattern 1 histology in 11/11 cases, pattern 2 in 30/32 (93.8%) and pattern 3 in 22/24 (91.6%). Sensitivity and specificity were 82% and 100%. In the control group there was 100% concordance between optical coherence tomography and histology. The overall concordance between optical coherence tomography and histology in determining patchy lesions was 75%.ConclusionOptical coherence tomography could be a helpful diagnostic tool in children with mild or marked villous atrophy for diagnosing celiac disease during upper gastrointestinal (GI) endoscopy, avoiding biopsies. However, duodenal biopsies are mandatory if the optical coherence tomography shows normal villous morphology in patients with positive antibodies.     

Optical coherence tomography as a tool for percutaneous coronary interventions.

This study was performed to demonstrate the ability of intravascular optical coherence tomography (OCT) to identify characteristic vascular responses to percutaneous coronary interventions (PCI). OCT provides cross-sectional images of tissue in situ at approximately 10 microm, rendering detailed structural information. Intravascular ultrasound and OCT images were obtained from 10 patients before and after PCI. Images were evaluated to identify balloon-induced dissections/disruptions, thrombus, cutting balloon-induced vascular changes, tissue protrusion, stent apposition and symmetry, and intimal hyperplasia. The disrupted intima, intraluminal thrombus, depth of balloon-induced dissections, cutting balloon cuts, tissue prolapse, underdeployed struts, and intimal hyperplasia were all noticed with OCT. This is the first report of the use of OCT to identify in vivo human intracoronary pathology after PCI.     

光学相干断层成像在老年冠心病介入诊疗中的初步应用

目的探讨血管内光学相干断层成像（OCT）在老年冠心病介入诊疗中的作用和安全性，评价其临床价值。方法9例老年冠心病患者，行冠脉造影和OCT检查，比较二者对冠状动脉病变的显示情况：包括病变结构、管腔狭窄程度、斑块性质等，根据造影及OCT结果参照病人临床表现对于狭窄较重（造影直径狭窄率〉70％），或造影中等程度狭窄（直径狭窄率介于50％～70％），但OCT狭窄相对较重（OCT管腔面积狭窄率〉60％）并伴有不稳定斑块的病变进行球囊扩张和支架植入治疗，并用OCT评价支架植入后的即时效果。结果与冠脉造影相比，血管内OCT能直观、清晰、实时地显示病变冠脉的管腔狭窄程度、微观组织结构、斑块组成性质及支架植入后靶病变血管及支架的形态特征。结论OCT在老年冠心病患者中的操作安全易行，能够精确测量病变血管狭窄程度、清晰观测管腔微观结构特征，明确斑块特征，指导支架植入及观测支架植入后的即刻效果，对老年冠心病人介入治疗具有指导作用。     

Pitfalls of angiography in the assessment of atherosclerosis: the role of optical coherence tomography

We report the case of a patient presenting with unstable angina, in whom information obtained by coronary angiography was inconclusive for the existence of a culprit lesion in the ostium of the right coronary artery. The use of optical coherence tomography was required for proper lesion assessment.     

Optical coherence tomography to identify the cause of an arrhythmic storm:A case report

A 56-year-old man experienced an aborted sudden death followed by an arrhythmic storm. Angiography revealed a non-severe lesion on the left circumflex artery that was treated medically but an arrhythmic storm recurred. A repeat angiogram was comparable but optical coherence tomography imaging revealed a ruptured plaque with intraluminal thrombosis. Percutaneous coronary intervention was performed and no arrhythmia recurred.