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Objective: We propose a method utilizing mixed reality (MR) goggles (HoloLens 2, Microsoft) to facilitate impacted canine alignment, as planning the traction direction and force delivery could benefit from 3D data visualization using mixed reality (MR)., Methods: Cone-beam CT scans featuring isometric resolution and low noise-to-signal ratio were semi-automatically segmented in Inobitec software. The exported 3D mesh (OBJ file) was then optimized for the HoloLens 2. Using the Unreal Engine environment, we developed an application for the HoloLens 2, implementing HoloLens SDK and UX Tools. Adjustable pointers were added for planning attachment placement, traction direction, and point of force application. The visualization was presented to participants of a course on impacted teeth treatment, followed by a 10-question survey addressing potential advantages (5-point scale: 1 = totally agree, 5 = totally disagree)., Results: Out of 38 respondents, 44.7% were orthodontists, 34.2% dentists, 15.8% dental students, and 5.3% dental technicians. Most respondents (44.7%) were between 35 and 44 years old, and only 1 (2.6%) respondent was 55-64 years old. Median answers for six questions were 'totally agree' (25th percentile 1, 75th percentile 2) and for four questions 'agree' (25th percentile 1, 75th percentile 2). No correlation was found between age, profession, and responses., Conclusion: Our method generated substantial interest among clinicians. The initial responses affirm the potential benefits, supporting the continued exploration of MR-based techniques for the treatment of impacted teeth. However, the recommendation for widespread use awaits validation through clinical trials., (© 2024 The Authors. Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

The most commonly applied way of teaching students to convey the foundations of human anatomy and physiology involves textbooks and lectures. This way of transmitting knowledge causes difficulties for students, especially in the context of three-dimensional imaging of organ structures, and as a consequence translates into difficulties with imagining them. Even despite the rapid uptake of knowledge dissemination provided by online materials, including courses and webinars, there is a clear need for learning programs featuring first-hand immersive experiences tailored to suit individual study paces. In this paper, we present an approach to enhance a classical study program by combining multi-modality data and representing them in a Mixed Reality (MR)-based environment. The advantages of the proposed approach have been proven by the conducted investigation of the relationship between atrial anatomy, its electrophysiological characteristics, and resulting P wave morphology on the electrocardiogram (ECG). Another part of the paper focuses on the role of the sinoatrial node in ECG formation, while the MR-based visualization of combined micro-computed tomography (micro-CT) data with non-invasive CineECG imaging demonstrates the educational application of these advanced technologies for teaching cardiac anatomy and ECG correlations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Potyagaylo, van Dam, Kuniewicz, Dolega-Dolegowski, Pregowska, Atkinson, Dobrzynski and Proniewska.)

This paper aims to thoroughly discuss the impact of artificial intelligence (AI) on clinical practice in interventional cardiology (IC) with special recognition of its most recent advancements. Thus, recent years have been exceptionally abundant in advancements in computational tools, including the development of AI. The application of AI development is currently in its early stages, nevertheless new technologies have proven to be a promising concept, particularly considering IC showing great impact on patient safety, risk stratification and outcomes during the whole therapeutic process. The primary goal is to achieve the integration of multiple cardiac imaging modalities, establish online decision support systems and platforms based on augmented and/or virtual realities, and finally to create automatic medical systems, providing electronic health data on patients. In a simplified way, two main areas of AI utilization in IC may be distinguished, namely, virtual and physical. Consequently, numerous studies have provided data regarding AI utilization in terms of automated interpretation and analysis from various cardiac modalities, including electrocardiogram, echocardiography, angiography, cardiac magnetic resonance imaging, and computed tomography as well as data collected during robotic-assisted percutaneous coronary intervention procedures. Thus, this paper aims to thoroughly discuss the impact of AI on clinical practice in IC with special recognition of its most recent advancements.

Tooth anatomy is fundamental knowledge used in everyday dental practice to reconstruct the occlusal surface during cavity fillings. The main objective of this project was to evaluate the suitability of two types of anatomical tooth reference models used to support reconstruction of the occlusal anatomy of the teeth: (1) a three-dimensional (3D)-printed model and (2) a model displayed in augmented reality (AR) using Microsoft HoloLens. The secondary objective was to evaluate three aspects impacting the outcome: clinical experience, comfort of work, and other variables. The tertiary objective was to evaluate the usefulness of AR in dental education. Anatomical models of crowns of three different molars were made using cone beam computed tomography image segmentation, printed with a stereolithographic 3D-printer, and then displayed in the HoloLens. Each participant reconstructed the occlusal anatomy of three teeth. One without any reference materials and two with an anatomical reference model, either 3D-printed or holographic. The reconstruction work was followed by the completion of an evaluation questionnaire. The maximum Hausdorff distances (Hmax) between the superimposed images of the specimens after the procedures and the anatomical models were then calculated. The results showed that the most accurate but slowest reconstruction was achieved with the use of 3D-printed reference models and that the results were not affected by other aspects considered. For this method, the Hmax was observed to be 630 μm (p = 0.004). It was concluded that while AR models can be helpful in dental anatomy education, they are not suitable replacements for physical models., (© 2022 The Authors. Anatomical Sciences Education published by Wiley Periodicals LLC on behalf of American Association for Anatomy.)

Objectives: Virtual Reality (VR) has been widely used in psychiatry, including psychotic disorders. The main advantage of VR is its high ecological validity and controllability of the virtual environment. Our main goal was to test whether, similarly to computer-generated VR, 360-degree videos are able to elicit a state of social paranoia in prone individuals., Methods: Sixteen schizophrenia patients and twenty-three healthy individuals were assessed using Leibowitz Social Anxiety Scale and additionally, in the patient group, the Positive and Negative Syndrome Scale (PANSS-6) and Peters Delusional Inventory (PDI) were used. The participants viewed four 360-degree videos with and without social content on a VR headset. Meanwhile, subjects' heart rate was measured continuously. After the exposure, both groups were assessed with Social State Paranoia Scale (SSPS) and asked about momentary anxiety and sense of presence., Results: The schizophrenia patients reported higher momentary anxiety, although the results of SSPS did not differ significantly between groups. In the control group the heart rate decreased between first non-social and social video, whereas in the patient group it did not differ significantly. There was a significant correlation of paranoid ideation experienced on daily basis (PDI) and elicited in VR (SSPS) in the patient group., Conclusions: In conclusion, paranoid responses can be triggered in patients with schizophrenia by 360-degree videos.

Background: The Augmented Reality (AR) blends digital information with the real world. Thanks to cameras, sensors, and displays it can supplement the physical world with holographic images. Nowadays, the applications of AR range from navigated surgery to vehicle navigation., Development: The purpose of this feasibility study was to develop an AR holographic system implementing Vertucci's classification of dental root morphology to facilitate the study of tooth anatomy. It was tailored to run on the AR HoloLens 2 (Microsoft) glasses. The 3D tooth models were created in Autodesk Maya and exported to Unity software. The holograms of dental roots can be projected in a natural setting of the dental office. The application allowed to display 3D objects in such a way that they could be rotated, zoomed in/out, and penetrated. The advantage of the proposed approach was that students could learn a 3D internal anatomy of the teeth without environmental visual restrictions., Conclusions: It is feasible to visualize internal dental root anatomy with AR holographic system. AR holograms seem to be attractive adjunct for learning of root anatomy., (© 2022. The Author(s).)

Three-dimensional (3D) printed model of the renal vasculature shows a high level of accuracy of subsequent divisions of both the arterial and the venous tree. However, minor artifacts appeared in the form of oval endings to the terminal branches of the vascular tree, contrary to the anticipated sharply pointed segments. Unfortunately, selective laser sintering process does not currently permit to present the arterial, venous and urinary systems in distinct colors, hence topographic relationship between the vascular and the pelvicalyceal systems is difficult to attain. Nonetheless, the 3D printed model can be used for educational purposes to demonstrate the vast renal vasculature and may also serve as a reference model whilst evaluating morphological anomalies of the intrarenal vasculature in a surgical setting.

Diabetic retinopathy (DR) is a diabetes disorder that disturbs human vision. It starts due to the damage in the light-sensitive tissues of blood vessels at the retina. In the beginning, DR may show no symptoms or only slight vision issues, but in the long run, it could be a permanent source of impaired vision, simply known as blindness in the advanced as well as in developing nations. This could be prevented if DR is identified early enough, but it can be challenging as we know the disease frequently shows rare signs until it is too late to deliver an effective cure. In our work, we recommend a framework for severity grading and early DR detection through hybrid deep learning Inception-ResNet architecture with smart data preprocessing. Our proposed method is composed of three steps. Firstly, the retinal images are preprocessed with the help of augmentation and intensity normalization. Secondly, the preprocessed images are given to the hybrid Inception-ResNet architecture to extract the vector image features for the categorization of different stages. Lastly, to identify DR and decide its stage (e.g., mild DR, moderate DR, severe DR, or proliferative DR), a classification step is used. The studies and trials have to reveal suitable outcomes when equated with some other previously deployed approaches. However, there are specific constraints in our study that are also discussed and we suggest methods to enhance further research in this field.

Various conventional approaches have been reported for the synthesis of nanomaterials without optimizing the role of synthesis parameters. The unoptimized studies not only raise the process cost but also complicate the physicochemical characteristics of the nanostructures. The liquid-plasma reduction with optimized synthesis parameters is an environmentally friendly and low-cost technique for the synthesis of a range of nanomaterials. This work is focused on the statistically optimized production of silver nanoparticles (AgNPs) by using a liquid-plasma reduction process sustained with an argon plasma jet. A simplex centroid design (SCD) was made in Minitab statistical package to optimize the combined effect of stabilizers on the structural growth and UV absorbance of AgNPs. Different combinations of glucose, fructose, sucrose and lactose stabilizers were tested at five different levels (-2, -1, 0, 1, 2) in SCD. The effect of individual and mixed stabilizers on AgNPs growth parameters was assumed significant when p-value in SCD is less than 0.05. A surface plasmon resonance band was fixed at 302 nm after SCD optimization of UV results. A bond stretching at 1633 cm -1 in FTIR spectra was assigned to C=O, which slightly shifts towards a larger wavelength in the presence of saccharides in the solution. The presence of FCC structured AgNPs with an average size of 15 nm was confirmed from XRD and EDX spectra under optimized conditions. The antibacterial activity of these nanoparticles was checked against Staphylococcus aureus and Escherichia coli strains by adopting the shake flask method. The antibacterial study revealed the slightly better performance of AgNPs against Staph. aureus strain than Escherichia coli .

Data on long-term neointimal healing and neoatherosclerosis progression after primary percutaneous coronary intervention (PCI) with implantation of everolimus-eluting bioresorbable vascular scaffold (BVS) (ABSORB BVS 1.0, Abbott Vascular) are limited. The mechanisms underlying very late scaffold failure remain to be further elucidated. This study sought to assess healing pattern and presence of neoatherosclerosis. This was a single-center, prospective, longitudinal study with serial optical coherence tomography (OCT) assessment at baseline, 12, 24 and 60 months after PCI performed in 12 patients presenting with ST-segment elevation myocardial infarction (STEMI). The median follow-up was 59 months. The diameter stenosis increased from 7.11 ± 4.99% at 1-year to 21.00 ± 11.31% at 5 years, (p = 0.03), whereas minimum lumen diameter remained stable throughout the follow-up period, as assessed by angiography. Minimum and mean lumen area declined over the 5-year follow-up by 1.00 ± 1.57 mm2 and 1.75 ± 0.87 mm2, respectively; a significant decrease in minimum and mean lumen area in the first two years, was followed by stable luminal dimensions between 2 and 5 years of follow-up. The lumen eccentricity (0.85 ± 0.03) and asymmetry (0.43 ± 0.10) indexes showed no change over 60-month follow-up. The incidence of atherosclerosis was high both in the in-scaffold (IS) and out-scaffold (OS) regions consisting of calcifications (IS = 100%, OS = 92%, p = 0.99), macrophages (IS = 92% and OS = 67%, p = 0.31), neovascularization (IS = 75%, OS = 50%, p = 0.40). In conclusion, serial OCT imaging up to 5 years after implantation of BVS in STEMI indicated complete scaffold resorption, stable lumen area following period of neointima growth in the first two years after PCI and high incidence of neoatherosclerosis., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: General data protection regulation (GDPR) provides rules according to which data should be managed and processed in a secure and appropriate way for patient requirements and security. Currently, everyone in Europe is covered by GDPR. Thus, the medical practice also requires access to patient data in a safe and secure way., Methods: Holographic technology allows users to see everything visible on a computer screen in a new and less restricted way, i.e. without the limitations of traditional computers and screens., Results: In this study, a three-dimensional holographic doctors' assistant is designed and implemented in a way that meets the GDPR requirements. The HoloView application, which is tailored to run on Microsoft HoloLens, is proposed toallow display and access to personal data and so-called sensitive information of all individual patients without the risk that it will be presented to unauthorized persons., Conclusions: To enhance the user experience and remain consistent with GSPR, a holographic desk is proposed that allows displaying patient data and sensitive information only in front of the doctor's eyes using mixed reality glasses. Last but not least, it boasts of a reduction in infection risk for the staff during the COVID-19 pandemic, affording medical care to be carried out by as few doctors as possible.

Background: Peri-strut low intensity areas (PLIA) visualized by optical coherence tomography (OCT) have been related to neointimal proliferation and increased incidence of target lesion revascularization in stable coronary artery disease. The aim of this study was to determine the association between PLIA by OCT and the long-term vascular healing response after bioresorbable scaffold (BRS) implantation in the setting of ST-segment elevation myocardial infarction (STEMI)., Methods: This is a single-centre, longitudinal, cohort study with a serial: baseline, 1, 2 and 5 years OCT evaluation of neointimal response (lumen area and neoatherosclerosis) after percutaneous coronary intervention (PCI) with BRS Absorb™ 1.0 implantation in patients presenting with STEMI. PLIA was analyzed in every cross section and scored: 0-no PLIA; 1-PLIA < 1 quadrant; 2-PLIA ≥ 1 and <2 quadrants; 3-PLIA ≥ 2 and <3 quadrants; 4-PLIA in ≥3 quadrants., Results: Of the 23 patients implanted BRS, 18 completed 2-year follow-up, whereas complete OCT data up to 5 years were available in 12 patients. Presence of PLIA was identified in 100% patients at 1 and 2 years, whereas at 5 years neither PLIA nor scaffold struts were visualized by OCT. Neoatherosclerosis was identified in 73,68% patients after 1 year and in all patients at 2 and 5 years. The mean PLIA score > 1 at 2 years was associated with greater percentage of minimum lumen area decrease after 2 years from index procedure., Conclusions: The extent of PLIA by OCT at 2 years after primary PCI with BRS was associated with lumen area decrease. Neoatherosclerosis formation was detected in all patients at 2 and 5 years. PLIA assessment could serve as an additive means to predict neointimal healing pattern after next generation BRS implantation., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: There is paucity of data on acute performance of Fantom (REVA Medical, CA), a second generation sirolimus-eluting bioresorbable scaffold (BRS), in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention. The aim of this study was to evaluate safety and efficacy of the Fantom BRS in the acute setting of STEMI characterized by thrombogenic milieu., Methodology: Ten STEMI patients treated with a sirolimus-eluting Fantom BRS were enrolled into prospective, observational study. The scaffold sizing, positioning, and optimization were optical coherence tomography (OCT) guided. The primary end-point was the device-oriented composite endpoint (DOCE), additionally angiographic and OCT analysis were performed., Results: The primary-end point, defined as DOCE, did not occur in any patient within the 30-day follow-up. The procedural and angiographic success rates were both 100%, there was no case of scaffold thrombosis, target lesion revascularization nor death. In QCA, an in-device minimum lumen diameter was 2.89 ± 0.24 mm and the residual diameter stenosis was 3.56 ± 3.17%. OCT revealed an incomplete scaffold apposition in five patients with an average of seven malapposed struts per scaffold and mean distance of 120 ± 30 μm. There was no proximal edge dissection, the distal edge dissection was recorded in one patient., Conclusions: This is the first pilot study evaluating safety and efficacy of the Fantom BRS, a second generation fully bioresorbable coronary scaffold, in STEMI patients undergoing primary PCI with OCT guidance. Fantom BRS showed adequate safety and efficacy in the acute 30-day angiographic, OCT, and clinical follow-up., (© 2019 Wiley Periodicals, Inc.)

Background and Objective: People suffer from sleep disorders caused by work-related stress, irregular lifestyle or mental health problems. Therefore, development of effective tools to diagnose sleep disorders is important. Recently, to analyze biomedical signals Information Theory is exploited. We propose efficient classification method of sleep anomalies by applying entropy estimating algorithms to encoded ECGs signals coming from patients suffering from Sleep-Related Breathing Disorders (SRBD)., Methods: First, ECGs were discretized using the encoding method which captures the biosignals variability. It takes into account oscillations of ECG measurements around signals averages. Next, to estimate entropy of encoded signals Lempel-Ziv complexity algorithm (LZ) which measures patterns generation rate was applied. Then, optimal encoding parameters, which allow distinguishing normal versus abnormal events during sleep with high sensitivity and specificity were determined numerically. Simultaneously, subjects' states were identified using acoustic signal of breathing recorded in the same period during sleep., Results: Random sequences show normalized LZ close to 1 while for more regular sequences it is closer to 0. Our calculations show that SRBDs have normalized LZ around 0.32 (on average), while control group has complexity around 0.85. The results obtained to public database are similar, i.e. LZ for SRBDs around 0.48 and for control group 0.7. These show that signals within the control group are more random whereas for the SRBD group ECGs are more deterministic. This finding remained valid for both signals acquired during the whole duration of experiment, and when shorter time intervals were considered. Proposed classifier provided sleep disorders diagnostics with a sensitivity of 93.75 and specificity of 73.00%. To validate our method we have considered also different variants as a training and as testing sets. In all cases, the optimal encoding parameter, sensitivity and specificity values were similar to our results above., Conclusions: Our pilot study suggests that LZ based algorithm could be used as a clinical tool to classify sleep disorders since the LZ complexities for SRBD positives versus healthy individuals show a significant difference. Moreover, normalized LZ complexity changes are related to the snoring level. This study also indicates that LZ technique is able to detect sleep abnormalities in early disorders stage., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objectives: To assess feasibility, safety, angiographic, and clinical outcome of highly-calcific carotid stenosis (HCCS) endovascular management using CGuard™ dual-layer carotid stents., Background: HCCS has been a challenge to carotid artery stenting (CAS) using conventional stents. CGuard combines a high-radial-force open-cell frame conformability with MicroNet sealing properties., Methods: The PARADIGM study is prospectively assessing routine CGuard use in all-comer carotid revascularization patients; the focus of the present analysis is HCCS versus non-HCCS lesions. Angiographic HCCS (core laboratory evaluation) required calcific segment length to lesion length ≥2/3, minimal calcification thickness ≥3 mm, circularity (≥3 quadrants), and calcification severity grade ≥3 (carotid calcification severity scoring system [CCSS]; G0-G4)., Results: One hundred and one consecutive patients (51-86 years, 54.4% symptomatic; 106 lesions) received CAS (16 HCCS and 90 non-HCCS); eight others (two HCCS) were treated surgically. CCSS evaluation was reproducible, with weighted kappa (95% CI) of 0.73 (0.58-0.88) and 0.83 (0.71-0.94) for inter- and intra-observer reproducibility respectively. HCCS postdilatation pressures were higher than those in non-HCCS; 22 (20-24) versus 20 (18-24) atm, p = .028; median (Q1-Q3). Angiography-optimized HCCS-CAS was feasible and free of contrast extravasation or clinical complications. Overall residual diameter stenosis was single-digit but it was higher in HCCS; 9 (4-17) versus 3 (1-7) %, p = .002. At 30 days and 12 months HCCS in-stent velocities were normal and there were no adverse clinical events., Conclusion: CGuard HCCS endovascular management was feasible and safe. A novel algorithm to grade carotid artery calcification severity was reproducible and applicable in clinical study setting. Larger HCCS series and longer-term follow-up are warranted., (© 2019 Wiley Periodicals, Inc.)

The aim of this study was to compare the measures of luminal stenosis between the two-dimensional (2D) and three-dimensional (3D) Quantitative Vessel Analysis (QVA) generated by CAAS QVA software and intravascular ultrasound (IVUS). Invasive contrast angiography is considered gold standard for diagnostic imaging and intervention in both coronary and peripheral arterial disease. However, it is based on 2D images depicting complicated 3D arterial anatomy. To overcome these limitations, 3D QVA has been developed to bridge the gap between 2D QVA and endovascular imaging. Thirty porcine femoral angiograms (common, profunda and superficial) with matching intravascular ultrasound (IVUS) pullbacks featuring variable degree of stenosis were analysed by 2D QVA, 3D QVA and quantitative IVUS. All 3 modalities provided similar data regarding the length of the investigated segment. Median lumen diameter was nearly identical in IVUS (4.69 mm) and in 3D QVA (4.76 mm) but quite a bit lower in 2D QVA (4.47 mm, Kruskal-Wallis test p = 0.1648). Lumen area measured in 2D QVA was lower than in IVUS and in 3D QVA. Lumen areas rendered by IVUS and 3D QVA were similar. Bland-Altman plots showed that the lowest differences were observed between IVUS and 3D QVA. IVUS and 3D QVA results were consistently higher than 2D QVA. 3D QVA is a useful surrogate of IVUS for precise luminal morphology measurements of peripheral arteries, rendering results that are much closer to IVUS than 2D QVA can provide.

Early-generation drug-eluting stents (DES) have been demonstrated to delay vascular healing. Limited optical coherence tomography (OCT) data on the very long-term neointimal response after DES implantation are available. The aim of this study was a serial OCT assessment of neointimal thickness, stent strut coverage, malapposition, and protrusion as markers of neointimal response at 3 and 9 years after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES). In this single-centre, longitudinal study consecutive patients undergoing elective PCI with SES or PES were included. OCT analysis was performed after 3 and 9 years by the independent core laboratory. A total of 22 subjects (8 SES and 14 PES) underwent an OCT assessment at 3 and 9 years post index procedure. The lumen, neointimal and malapposition area and the neointimal thickness (SES ∆50 µm, p = 0.195, PES ∆10 µm, p = 0.951) did not change significantly over the 6 year follow-up. No differences in the incidence of uncovered, malapposed or protruding struts were found in each type of stent. At 3 and 9 years after PCI, implantation of early-generation SES and PES may be associated with similar neointimal thickness, strut coverage, malapposition and protrusion, as assessed by serial OCT examination among patients with uneventful follow-up at 3 years post procedure. The small size of the study warrants judicious interpretation of our results and confirmation in larger multimodality imaging studies, including patients treated with contemporary stent platforms.

Aims: The aim of the study was to assess the vascular healing response after Absorb bioresorbable vascular scaffold (BVS) implantation in patients with ST-segment elevation myocardial infarction (STEMI) utilising truly serial optical coherence tomography (OCT) examination at baseline, 12 and 24 months., Methods and Results: This was a single-centre, prospective, longitudinal study with baseline, 12- and 24-month OCT evaluation of 18 STEMI patients treated with 22 Absorb BVS. The healing pattern was evaluated based upon lumen area, neointimal hyperplasia, strut coverage and apposition. The lumen area decreased at 12 months compared to baseline (8.52±1.69 mm² vs. 7.0±1.70 mm², p<0.01), but it did not change from that point onwards up to 24 months (7.0±1.70 mm² vs. 6.94±1.65 mm², p=0.92). At 12 months after the index procedure, the mean neointimal thickness was 217±69 μm and further neointimal hyperplasia was observed between 12 and 24 months though less pronounced (Δ62±44 μm, p<0.0001). Full circumferential coverage of the vessel wall by neointima was observed in 92% of frames at 24 months. The low number of malapposed struts at the index procedure (<5%) further decreased over the observation period and was found in only one patient at 12 and 24 months. The ratio of uncovered struts was low at both 12 and 24 months., Conclusions: This serial OCT analysis of the second-generation everolimus-eluting BVS in a STEMI population confirmed a favourable healing pattern as expressed by moderate neointimal growth, preserved lumen area and no late acquired malapposition.

Background: Fractional flow reserve (FFR) assesses a functional impact of the atheroma on the myocardial ischemia, but it does not take into account the morphology of the lesion. Previous optical coherence tomography (OCT), intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) studies presented their potential to detect vulnerable plaques, which is not possible by FFR assessment. With the following study, the intermediate lesions were assessed by FFR, OCT and combined NIRS-IVUS imaging to identify plaque vulnerability., Methods: Thirteen intermediate lesions were analyzed simultaneously by FFR, OCT and combined NIRS-IVUS imaging., Results: Two lesions were found to have FFR ≤ 0.80 (0.65 and 0.76). The other 11 lesions had FFR > 0.80 with a mean FFR 0.88 ± 0.049. Two lesions with FFR ≤ 0.80 had plaque burden (PB) > 70% and minimal lumen area (MLA) < 4 mm2, but neither of these 2 lesions were identified as OCT de-fined thin fibrous cap atheroma (TCFA), or NIRS-IVUS possible TCFA. Among the other 11 lesions with FFR > 0.80, 8 were identified as OCT-defined TCFA, 4 had PB > 70%, 6 had MLA < 4 mm2, 2 had both PB > 70% and MLA < 4 mm2, 3 lesions were identified as NIRS-IVUS possible TCFA, and 4 lesions had lipid core burden index > 400., Conclusions: The FFR-negative lesions pose traits of vulnerability as assessed simultaneously by IVUS, OCT and NIRS imaging.

Background: Early-generation drug-eluting stents (DESs) have been shown to accelerate neoatherogenesis. Limited optical coherence tomography (OCT) data on the very long-term neoatherosclerotic progression after DES implantation are available., Aim: The aim of this study was a serial OCT evaluation of neoatherosclerosis at three and nine years after implantation of sirolimus-eluting stents (SESs) and paclitaxel-eluting stents (PESs)., Methods: Consecutive patients undergoing elective percutaneous coronary intervention with SES (Cypher, Cordis) or PES (Taxus, Boston Scientific) were included in this single-centre, longitudinal study. OCT analysis was performed after three and nine years by an independent core laboratory., Results: A total of 39 OCT recordings were assessed at three years after the index procedure; of them, 22 (eight SES and 14 PES) OCT pullbacks were evaluated in a paired analysis at three and nine years post implantation. Overall, neoatheroscle-rosis was identified in 23.1% of stents at three years and in 30.8% at nine years after the index procedure (p = 0.289). No features of significant neoatherosclerotic progression were found in either group between three- and nine-year assessment., Conclusions: At nine years after implantation of early-generation DES no significant neoatherosclerotic progression was observed among patients with uneventful follow-up at three years after PCI, as assessed by OCT. These observations need to be confirmed in larger studies including the current generation of DESs.

Objectives: The aim of the study was to evaluate the healing process at 12 months after ABSORB™ bioresorbable vascular scaffold (BVS) implantation in patients with ST-segment elevation myocardial infarction (STEMI)., Background: There is currently no data on long-term BVS performance in the acute thrombotic setting. The underlying altered plaque pathomorphology may impact the neointima healing pattern, potentially making it different to that observed in stable coronary artery disease (CAD)., Methods: We have performed an angiographic and optical coherence tomography (OCT) 12-month follow-up of 19 STEMI patients who were treated with a BVS implantation (23 scaffolds). An independent core laboratory performed a paired analysis of the corresponding frames at baseline and follow-up., Results: At 12 months, the OCT follow-up showed a decrease in the mean lumen area (8.29 ± 1.53 mm(2) vs. 6.82 ± 1.57 mm(2) , P < 0.001), but no significant change in the mean scaffold area (8.49 ± 1.53 mm(2) vs. 8.90 ± 1.51 mm(2) ). Significant decreases in malapposed strut ratio (4.9 ± 8.65% vs. 0.4 ± 1.55%, P < 0.001) and malapposition area (0.29 ± 0.60 mm(2) 0.08 ± 0.32 mm(2) , P = 0.002) were observed. A nonhomogenous proliferation of neointima was revealed with a symmetry index of 0.15 (0.08-0.27), a mean neointima thickness of 203 μm (183-249) and mean neointima area of 2.07 ± 0.51 mm(2) . The quantitative coronary angiography showed late lumen loss of 0.08 ± 0.23 mm and no significant change in the minimal lumen diameter (P = 0.11). There were no major adverse cardiovascular events (MACE), except for one nontarget vessel revascularization., Conclusions: The OCT revealed a favorable healing pattern after BVS implantation in a STEMI population., (© 2015 Wiley Periodicals, Inc.)

Optical coherence tomography (OCT) has opened new horizons for intravascular coronary imaging. It utilizes near-infrared light to provide a microscopic insight into the pathology of coronary arteries in vivo. Optical coherence tomography is also capable of identifying the chemical composition of atherosclerotic plaques and detecting traits of their vulnerability. At present it is the only tool to measure the thickness of the fibrous cap covering the lipid core of the atheroma, and thus it is an exceptional modality to detect plaques that are prone to rupture (thin fibrous cap atheromas). Moreover, it facilitates distinguishing between plaque rupture and plaque erosion as a cause of acute intracoronary thrombosis. Optical coherence tomography is applied to guide angioplasties of coronary lesions and to assess outcomes of percutaneous coronary interventions broadly. It identifies stent malapposition, dissections, and thrombosis with unprecedented precision. Furthermore, OCT helps to monitor vessel healing after stenting. It evaluates the coverage of stent struts by the neointima and detects in-stent neoatherosclerosis. With so much potential, new studies are warranted to determine OCT's clinical impact. The following review presents the technical background, basics of OCT image interpretation, and practical tips for adequate OCT imaging, and outlines its established and potential clinical application.

Objectives: Variability in data acquisition from intervened coronary arteries could represent a source of error that has implications for the design of serial stent studies. We assessed inter-pullback reproducibility of volumetric grayscale and radiofrequency intravascular ultrasound (IVUS) data in stented coronary arteries., Design: Fifteen patients with coronary artery lesions treated with stent implantation were included and examined with two separate pullbacks using the Eagle Eye Gold-phased array 20 MHz IVUS catheter (Volcano). The arteries were divided into five segments, giving a total of 150 sub-segments for analyses. Matching of frames was performed using landmarks that were clearly visible in coronary angiography and intravascular pullbacks. Data were analyzed off-line at an independent Corelab., Results: The inter-pullback reproducibility of geometrical data was very good for non-stented segments with relative differences less than 5% between pullbacks for lumen-, vessel-, and plaque volumes. For stented segments reproducibility was poorer with relative differences between pullbacks in the range of 5-10%. The inter-pullback reproducibility of compositional data demonstrated large standard deviations of relative differences, indicating a weaker agreement., Conclusions: Agreements between pullbacks were weaker in stented than those in non-stented segments. Based on our data, future longitudinal IVUS studies in intervened vessels should account for a variability of 5-10% attributed to the acquisition of images.

Background: The amount of data comparing intravascular ultrasound (IVUS) and optical coherence tomography (OCT) for the detection of stent coverage in clinical settings is limited., Aim: To make a qualitative and quantitative assessment of the vascular healing patterns in patients after stent implantations visualised by both IVUS and OCT., Methods: Images were obtained in patients with clinical symptoms of angina, who had had a bare metal stent implanted in the previous 12 months. Angiography, IVUS and OCT were performed in 14 coronary arteries. Measurements of stent, lumen and neo-intima areas and dimensions were performed in stented regions and in both 10 mm references. IVUS, OCT, and angiographic data were compared in matched regions. Off-line analyses were performed by an independent core lab., Results: 14 stents were imaged without any procedural complications. The nominal stent length was 28 ± 4.5 mm. OCT was the most accurate technique for assessing stent length (28.12 ± 6.8 mm), while QCA underestimated length due to foreshortening (22.16 ± 6.39 mm) and IVUS was vulnerable to random error due to discontinuous pullbacks and vessel movements (24.21 ± 7.90 mm). Minimum lumen area (MLA) and minimum lumen diameter (MLD) in reference sites were comparable in IVUS and OCT, whereas there were significant differences between these two modalities for MLA (3.30 ± 1.49 vs. 2.19 ± 1.30 mm², p = 0.0046) and for MLD (2.42 ± 0.51 vs. 1.58 ± 0.56 mm², p = 0.0023) in stented segments. There was a slight overestimation of lumen volume (130.18 ± 70.61 vs. 117.82 ± 67.02 mm³, p = 0.7256),a marked overestimation of stent volume (179.29 ± 97.58 vs. 226.46 ± 108.76 mm³, p = 0.0544) and a statistically significant difference in the neointima volume (49.11 ± 39.70 vs. 108.64 ± 43.77 mm³, p = 0.0060) by IVUS compared to OCT. Mean neointima burden in IVUS was much smaller than in OCT (20.79 ± 14.27% vs. 58.16 ± 18.25%, p = 0.0033)., Conclusions: OCT can precisely quantify struts coverage and is more accurate than IVUS in the assessment of vascular healing in patients after stent implantation.

Intravascular ultrasound (IVUS) has been clinically available for almost 25 years now and showed us valuable information regarding the coronary vessel lumen, its dimensions, the plaque burden and plaque characteristics that we were not able to assess by angiography alone. Using these abilities, IVUS has helped us to start, understand the atherosclerotic process in the coronary vessels. Further technical innovations partially overcame the somewhat limited image resolution of IVUS allowing more in-depth characterization and quantification of coronary plaque components. In addition, IVUS has been shown to be helpful to guide interventional procedures including optimal stent deployment in many clinical situations. In this review, we focus on the potential role of IVUS technology in interventional cardiology and on the valuable role of IVUS usage in percutaneous coronary interventions.