The invasive assessment of coronary atherosclerosis and stents using optical coherence tomography: a clinical update

Clinical translation of handheld optical coherence tomography: practical considerations and recent advancements

Since the inception of optical coherence tomography (OCT), advancements in imaging system design and handheld probes have allowed for numerous advancements in disease diagnostics and characterization of the structural and optical properties of tissue. OCT system developers continue to reduce form factor and cost, while improving imaging performance (speed, resolution, etc.) and flexibility for applicability in a broad range of fields, and nearly every clinical specialty. An extensive array of components to construct customized systems has also become available, with a range of commercial entities that produce high-quality products, from single components to full systems, for clinical and research use. Many advancements in the development of these miniaturized and portable systems can be linked back to a specific challenge in academic research, or a clinical need in medicine or surgery. Handheld OCT systems are discussed and explored for various applications. Handheld systems are discussed in terms of their relative level of portability and form factor, with mention of the supporting technologies and surrounding ecosystem that bolstered their development. Additional insight from our efforts to implement systems in several clinical environments is provided. The trend toward well-designed, efficient, and compact handheld systems paves the way for more widespread adoption of OCT into point-of-care or point-of-procedure applications in both clinical and commercial settings.

Role of Cardiac PET in Clinical Practice

OPINION STATEMENT

Early identification of atherosclerosis and at-risk lesions plays a critical role in reducing the burden of cardiovascular disease. While invasive coronary angiography serves as the gold standard for diagnosing coronary artery disease, non-invasive imaging techniques provide visualization of both anatomical and functional atherosclerotic processes prior to clinical presentation. The development of cardiac positron emission tomography (PET) has greatly enhanced our capability to diagnose and treat patients with early stages of atherosclerosis. Cardiac PET is a powerful, versatile non-invasive diagnostic tool with utility in the identification of high-risk plaques, myocardial perfusion defects, and viable myocardial tissue. Cardiac PET allows for comparisons of myocardial function both at time of rest and stress, providing accurate assessments of both myocardial perfusion and viability. Furthermore, novel PET techniques with unique radiotracers yield clinically relevant data on high-risk plaques in active progressive atherosclerosis. While PET exercise stress tests were previously difficult to perform given short radiotracer half-life, the development of the novel radiotracer Flurpiridaz F-18 provides a promising future for PET exercise stress imaging. In addition, hybrid imaging with computed tomography angiography (CTA) and cardiac magnetic resonance (CMR) provides integration of cardiac function and structure. In this review article, we discuss the principles of cardiac PET, the clinical applications of PET in diagnosing and prognosticating patients at risk for future cardiovascular events, compare PET with other non-invasive cardiac imaging modalities, and discuss future applications of PET in CVD evaluation and management.

Optical coherence tomography imaging of the basal ganglia: feasibility and brief review

Optical coherence tomography (OCT) is a promising medical imaging technique that uses light to capture real-time cross-sectional images from biological tissues in micrometer resolution. Commercially available optical coherence tomography systems are employed in diverse applications, including art conservation and diagnostic medicine, notably in cardiology and ophthalmology. Application of this technology in the brain may enable distinction between white matter and gray matter, and obtainment of detailed images from within the encephalon. We present, herein, the in vivo implementation of OCT imaging in the rat brain striatum. For this, two male 60-day-old rats (Rattus norvegicus, Albinus variation, Wistar) were stereotactically implanted with guide cannulas into the striatum to guide a 2.7-French diameter high-definition OCT imaging catheter (Dragonfly™, St. Jude Medical, USA). Obtained images were compared with corresponding histologically stained sections to collect imaging samples. A brief analysis of OCT technology and its current applications is also reported, as well as intra-cerebral OCT feasibility on brain mapping during neurosurgical procedures.

Using optical coherence tomography to rapidly phenotype and quantify congenital heart defects associated with prenatal alcohol exposure

BACKGROUND

The most commonly used method to analyze congenital heart defects involves serial sectioning and histology. However, this is often a time-consuming process where the quantification of cardiac defects can be difficult due to problems with accurate section registration. Here we demonstrate the advantages of using optical coherence tomography, a comparatively new and rising technology, to phenotype avian embryo hearts in a model of fetal alcohol syndrome where a binge-like quantity of alcohol/ethanol was introduced at gastrulation.

RESULTS

The rapid, consistent imaging protocols allowed for the immediate identification of cardiac anomalies, including ventricular septal defects and misaligned/missing vessels. Interventricular septum thicknesses and vessel diameters for three of the five outflow arteries were also significantly reduced. Outflow and atrioventricular valves were segmented using image processing software and had significantly reduced volumes compared to controls. This is the first study to our knowledge that has 3D reconstructed the late-stage cardiac valves in precise detail to examine their morphology and dimensions.

CONCLUSIONS

We believe, therefore, that optical coherence tomography, with its ability to rapidly image and quantify tiny embryonic structures in high resolution, will serve as an excellent and cost-effective preliminary screening tool for developmental biologists working with a variety of experimental/disease models.