INTRODUCTION: Image integration is being used in ablation procedures. However, the success of this approach is dependent on the accuracy of the image integration process. This study aims to evaluate the in vivo accuracy and reliability of the integrated image. METHODS AND RESULTS: One hundred twenty-four patients undergoing radiofrequency (RF) ablation catheter ablation for atrial fibrillation (AF) were recruited for this study from three different centers. Cardiac computerized tomography (CT) was performed in all patients and a 3D image of the left atrium (LA) and pulmonary veins (PVs) was extracted for registration after segmentation using a software program (CartoMerge, Biosense Webster, Inc.). Different landmarks were selected for registration and compared. Surface registration was then done and the impact on integration and the landmarks was evaluated. The best landmark registration was achieved when the posterior points on the pulmonary veins were selected (5.6 +/- 3.2). Landmarks taken on the anterior wall, left atrial appendage (LAA) or the coronary sinus (CS) resulted in a larger registration error (9.1 +/- 2.5). The mean error for surface registration was 2.17 +/- 1.65. However, surface registration resulted in shifting of the initially registered landmark points leading to a larger error (from 5.6 +/- 3.2 to 9.2 +/- 2.1; 95% CI 4.2-3.05). CONCLUSION: Posterior wall landmarks at the PV-LA junction are the most accurate landmarks for image integration in respect to the target ablation area. The concurrent use of the present surface registration algorithm may result in shifting of the initial landmarks with loss of their initial correlation with the area of interest.
- MeSH
- Echocardiography * methods MeSH
- Atrial Fibrillation * diagnosis surgery MeSH
- Image Interpretation, Computer-Assisted methods instrumentation MeSH
- Catheter Ablation * methods MeSH
- Middle Aged MeSH
- Humans MeSH
- Tomography, X-Ray Computed methods MeSH
- Reproducibility of Results MeSH
- Heart Atria radiography MeSH
- Pulmonary Veins radiography MeSH
- Imaging, Three-Dimensional methods instrumentation MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Evaluation Study MeSH
Zdravotně sociální fakulta Jihočeské univerzity v Českých Budějovicích Radiofrekvenční katétrové ablace (RFKA) pro fibrilaci síní (FS) patří k dnes již etablovaným metodám nefarmakologické léčby této arytmie. Cílem těchto zákroků je vytvořit v levé (popř. i v pravé) síni sérii cirkumferenčních a lineárních lézí, které slouží k eliminaci spouštěčů arytmie a k modifikaci arytmogenního substrátu tak, aby se FS nebyla schopna v síních setrvale udržet. V poslední době jsme na poli této léčby byli svědky nebývalého rozvoje řady metod a technik, které všechny měly za cíl jediné: zvýšit úspěšnost a bezpečnost katétrových ablací prováděných pro FS. Jednou z těchto možností je použití různých zobrazovacích technik, které přinášejí detailnější pohled na anatomii cílového srdečního oddílu. Souhrnný článek přináší přehled současných dostupných literárních dat a shrnuje autorovy zkušenosti v této specifické oblasti včetně výsledků použití těchto metod.
Radiofrequency catheter ablations (RFCA) for atrial fibrillation (AF) belong to the established non-pharmacological therapy of this arrhythmia. The goal of the therapy is to create series of circumferential and linear lesions in either left atrium or both atria to eliminate triggers and perpetuators of AF. We have witnessed an enormous technical and methodological development in this area recently with the aim to increase efficacy and safety of RFCA for AF. One of such modality is different imaging techniques, which allow for a more precise definition of the target structures in the atria. This review article summarizes current literary data on the topic and brings also author’s personal experience in the area of imaging and image integration including the results of the retrospective trial using these methods.
- Keywords
- radiofrekvenční katétrová ablace, zobrazovací techniky, rotační angiografie, elektroanatomické mapování,
- MeSH
- Surgery, Computer-Assisted methods trends MeSH
- Echocardiography methods trends utilization MeSH
- Atrial Fibrillation surgery radiography ultrasonography MeSH
- Cardiovascular Surgical Procedures methods instrumentation MeSH
- Catheter Ablation methods trends MeSH
- Humans MeSH
- Tomography, X-Ray Computed MeSH
- Systems Integration MeSH
- Imaging, Three-Dimensional methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
Technological advances have greatly enhanced the specialty of radiation oncology by allowing more healthy tissue to be spared for the same or better tumour coverage. Developments in medical imaging are integral to radiation oncology, both for design of treatment plans and to localise the target for precise administration of radiation. At planning, definition of the tumour and healthy tissue is based on CT, augmented frequently with MRI and PET. At treatment, three-dimensional soft-tissue imaging can also be used to localise the target and tumour motion can be tracked with fluoroscopic imaging of radio-opaque markers implanted in or near the tumour. These developments allow changes in tumour position, size, and shape that take place during radiotherapy to be measured and accounted for to boost geometric accuracy and precision of radiation delivery. Image-guided treatment also enhances uniformity in doses administered in a population of patients, thus improving our ability to measure the effect of dosimetric and non-dosimetric factors on tumour and healthy tissue outcomes in clinical trials. Increased precision and accuracy of radiotherapy are expected to augment tumour control, reduce incidence and severity of toxic effects after radiotherapy, and facilitate development of more efficient shorter schedules than currently available.
2nd ed. xviii, 826 s. : il. ; 25 cm
- MeSH
- Diagnostic Imaging MeSH
- Image Processing, Computer-Assisted MeSH
- Publication type
- Handbook MeSH
- Conspectus
- Speciální počítačové metody. Počítačová grafika
- NML Fields
- lékařská informatika
Audio-visual integration has been shown to be present in a wide range of different conditions, some of which are processed through the dorsal, and others through the ventral visual pathway. Whereas neuroimaging studies have revealed integration-related activity in the brain, there has been no imaging study of the possible role of segregated visual streams in audio-visual integration. We set out to determine how the different visual pathways participate in this communication. We investigated how audio-visual integration can be supported through the dorsal and ventral visual pathways during the double flash illusion. Low-contrast and chromatic isoluminant stimuli were used to drive preferably the dorsal and ventral pathways, respectively. In order to identify the anatomical substrates of the audio-visual interaction in the two conditions, the psychophysical results were correlated with the white matter integrity as measured by diffusion tensor imaging.The psychophysiological data revealed a robust double flash illusion in both conditions. A correlation between the psychophysical results and local fractional anisotropy was found in the occipito-parietal white matter in the low-contrast condition, while a similar correlation was found in the infero-temporal white matter in the chromatic isoluminant condition. Our results indicate that both of the parallel visual pathways may play a role in the audio-visual interaction.
- MeSH
- Acoustic Stimulation MeSH
- Anisotropy MeSH
- White Matter physiology MeSH
- Adult MeSH
- Humans MeSH
- Brain Mapping MeSH
- Auditory Perception physiology MeSH
- Photic Stimulation MeSH
- Signal Detection, Psychological physiology MeSH
- Diffusion Tensor Imaging MeSH
- Imaging, Three-Dimensional MeSH
- Visual Perception physiology MeSH
- Visual Pathways physiology MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
A number of fluorescence microscopy techniques are described to study dynamics of fluorescently labeled proteins, lipids, nucleic acids, and whole organelles. However, for studies of plant plasma membrane (PM) proteins, the number of these techniques is still limited because of the high complexity of processes that determine the dynamics of PM proteins and the existence of cell wall. Here, we report on the usage of raster image correlation spectroscopy (RICS) for studies of integral PM proteins in suspension-cultured tobacco cells and show its potential in comparison with the more widely used fluorescence recovery after photobleaching method. For RICS, a set of microscopy images is obtained by single-photon confocal laser scanning microscopy (CLSM). Fluorescence fluctuations are subsequently correlated between individual pixels and the information on protein mobility are extracted using a model that considers processes generating the fluctuations such as diffusion and chemical binding reactions. As we show here using an example of two integral PM transporters of the plant hormone auxin, RICS uncovered their distinct short-distance lateral mobility within the PM that is dependent on cytoskeleton and sterol composition of the PM. RICS, which is routinely accessible on modern CLSM instruments, thus represents a valuable approach for studies of dynamics of PM proteins in plants.
- MeSH
- Cell Membrane chemistry MeSH
- Microscopy, Confocal methods MeSH
- Membrane Proteins analysis MeSH
- Image Processing, Computer-Assisted methods MeSH
- Plant Cells chemistry MeSH
- Spectrum Analysis methods MeSH
- Nicotiana chemistry MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Image processing in cryogenic electron tomography (cryoET) is currently at a similar state as Single Particle Analysis (SPA) in cryogenic electron microscopy (cryoEM) was a few years ago. Its data processing workflows are far from being well defined and the user experience is still not smooth. Moreover, file formats of different software packages and their associated metadata are not standardized, mainly since different packages are developed by different groups, focusing on different steps of the data processing pipeline. The Scipion framework, originally developed for SPA (de la Rosa-Trevín et al., 2016), has a generic python workflow engine that gives it the versatility to be extended to other fields, as demonstrated for model building (Martínez et al., 2020). In this article, we provide an extension of Scipion based on a set of tomography plugins (referred to as ScipionTomo hereafter), with a similar purpose: to allow users to be focused on the data processing and analysis instead of having to deal with multiple software installation issues and the inconvenience of switching from one to another, converting metadata files, managing possible incompatibilities, scripting (writing a simple program in a language that the computer must convert to machine language each time the program is run), etcetera. Additionally, having all the software available in an integrated platform allows comparing the results of different algorithms trying to solve the same problem. In this way, the commonalities and differences between estimated parameters shed light on which results can be more trusted than others. ScipionTomo is developed by a collaborative multidisciplinary team composed of Scipion team engineers, structural biologists, and in some cases, the developers whose software packages have been integrated. It is open to anyone in the field willing to contribute to this project. The result is a framework extension that combines the acquired knowledge of Scipion developers in close collaboration with third-party developers, and the on-demand design of functionalities requested by beta testers applying this solution to actual biological problems.
The analysis and segmentation of articular cartilage magnetic resonance (MR) images belongs to one of the most commonly routine tasks in diagnostics of the musculoskeletal system of the knee area. Conventional regional segmentation methods, which are based either on the histogram partitioning (e.g., Otsu method) or clustering methods (e.g., K-means), have been frequently used for the task of regional segmentation. Such methods are well known as fast and well working in the environment, where cartilage image features are reliably recognizable. The well-known fact is that the performance of these methods is prone to the image noise and artefacts. In this context, regional segmentation strategies, driven by either genetic algorithms or selected evolutionary computing strategies, have the potential to overcome these traditional methods such as Otsu thresholding or K-means in the context of their performance. These optimization strategies consecutively generate a pyramid of a possible set of histogram thresholds, of which the quality is evaluated by using the fitness function based on Kapur's entropy maximization to find the most optimal combination of thresholds for articular cartilage segmentation. On the other hand, such optimization strategies are often computationally demanding, which is a limitation of using such methods for a stack of MR images. In this study, we publish a comprehensive analysis of the optimization methods based on fuzzy soft segmentation, driven by artificial bee colony (ABC), particle swarm optimization (PSO), Darwinian particle swarm optimization (DPSO), and a genetic algorithm for an optimal thresholding selection against the routine segmentations Otsu and K-means for analysis and the features extraction of articular cartilage from MR images. This study objectively analyzes the performance of the segmentation strategies upon variable noise with dynamic intensities to report a segmentation's robustness in various image conditions for a various number of segmentation classes (4, 7, and 10), cartilage features (area, perimeter, and skeleton) extraction preciseness against the routine segmentation strategies, and lastly the computing time, which represents an important factor of segmentation performance. We use the same settings on individual optimization strategies: 100 iterations and 50 population. This study suggests that the combination of fuzzy thresholding with an ABC algorithm gives the best performance in the comparison with other methods as from the view of the segmentation influence of additive dynamic noise influence, also for cartilage features extraction. On the other hand, using genetic algorithms for cartilage segmentation in some cases does not give a good performance. In most cases, the analyzed optimization strategies significantly overcome the routine segmentation methods except for the computing time, which is normally lower for the routine algorithms. We also publish statistical tests of significance, showing differences in the performance of individual optimization strategies against Otsu and K-means method. Lastly, as a part of this study, we publish a software environment, integrating all the methods from this study.
The mouse third molar (M3) develops postnatally and is thus a unique model for studying the integration of a non-mineralized tooth with mineralized bone. This study assessed the morphogenesis of the mouse M3, related to the alveolar bone, comparing M3 development with that of the first molar (M1), the most common model in odontogenesis. The mandibular M3 was evaluated from initiation to eruption by morphology and by assessing patterns of proliferation, apoptosis, osteoclast distribution, and gene expression. Three-dimensional reconstruction and explant cultures were also used. Initiation of M3 occurred perinatally, as an extension of the second molar (M2) which grew into a region of soft mesenchymal tissue above the M2, still far away from the alveolar bone. The bone-free M3 bud gradually became encapsulated by bone at the cap stage at postnatal day 3. Osteoclasts were first visible at postnatal day 4 when the M3 came into close contact with the bone. The number of osteoclasts increased from postnatal day 8 to postnatal day 12 to form a space for the growing tooth. The M3 had erupted by postnatal day 26. The M3, although smaller than the M1, passed through the same developmental stages over a similar time span but showed differences in initiation and in the timing of bone encapsulation.
- MeSH
- Apoptosis physiology MeSH
- Biomarkers analysis MeSH
- Fibroblast Growth Factor 4 analysis MeSH
- In Situ Hybridization MeSH
- Isoenzymes analysis MeSH
- Tooth Calcification physiology MeSH
- Acid Phosphatase analysis MeSH
- Mandible anatomy & histology growth & development MeSH
- Molar, Third anatomy & histology growth & development MeSH
- Molar anatomy & histology growth & development MeSH
- Morphogenesis physiology MeSH
- Mice MeSH
- Odontogenesis physiology MeSH
- Enamel Organ anatomy & histology growth & development MeSH
- Osteoblasts physiology MeSH
- Osteogenesis physiology MeSH
- Osteoclasts physiology MeSH
- Image Processing, Computer-Assisted methods MeSH
- Alveolar Process anatomy & histology growth & development MeSH
- Cell Proliferation MeSH
- Proliferating Cell Nuclear Antigen analysis MeSH
- Tooth Eruption physiology MeSH
- Hedgehog Proteins analysis MeSH
- Bone Resorption pathology physiopathology MeSH
- Tissue Culture Techniques MeSH
- Imaging, Three-Dimensional methods MeSH
- Tooth Root anatomy & histology growth & development MeSH
- Tooth Germ anatomy & histology growth & development MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
INTRODUCTION: Path integration (PI) is an important component of spatial navigation that integrates self-motion cues to allow the subject to return to a starting point. PI depends on the structures affected early in the course of Alzheimer's disease (AD) such as the medial temporal lobe and the parietal cortex. OBJECTIVES: To assess whether PI is impaired in patients with mild AD and amnestic mild cognitive impairment (aMCI) and to investigate the role of the hippocampus, entorhinal and inferior parietal cortex in this association. METHODS: 27 patients with aMCI, 14 with mild AD and 18 controls completed eight trials of Arena Path Integration Task. The task required subjects with a mask covering their eyes to follow an enclosed triangle pathway through two previously seen places: start-place1-place2-start. Brains were scanned at 1.5T MRI and respective volumes and thicknesses were derived using FreeSurfer algorithm. RESULTS: Controlling for age, education, gender and Mini-Mental State Examination score the aMCI and AD subjects were impaired in PI accuracy on the pathway endpoint (p=0.042 and p=0.013) compared to controls. Hippocampal volume and thickness of entorhinal and parietal cortices explained separately 36-45% of the differences in PI accuracy between controls and aMCI and 28-31% of the differences between controls and AD subjects. CONCLUSIONS: PI is affected in aMCI and AD, possibly as a function of neurodegeneration in the medial temporal lobe structures and the parietal cortex. PI assessment (as a part of spatial navigation testing) may be useful for identification of patients with incipient AD.
- MeSH
- Alzheimer Disease complications diagnostic imaging MeSH
- Cognitive Dysfunction complications diagnostic imaging MeSH
- Humans MeSH
- Magnetic Resonance Imaging MeSH
- Brain diagnostic imaging MeSH
- Neuropsychological Tests MeSH
- Perceptual Disorders diagnostic imaging etiology MeSH
- Image Processing, Computer-Assisted MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Case-Control Studies MeSH
- Space Perception physiology MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
