State of the art: iterative CT reconstruction techniques

Owing to recent advances in computing power, iterative reconstruction (IR) algorithms have become a clinically viable option in computed tomographic (CT) imaging. Substantial evidence is accumulating about the advantages of IR algorithms over established analytical methods, such as filtered back projection. IR improves image quality through cyclic image processing. Although all available solutions share the common mechanism of artifact reduction and/or potential for radiation dose savings, chiefly due to image noise suppression, the magnitude of these effects depends on the specific IR algorithm. In the first section of this contribution, the technical bases of IR are briefly reviewed and the currently available algorithms released by the major CT manufacturers are described. In the second part, the current status of their clinical implementation is surveyed. Regardless of the applied IR algorithm, the available evidence attests to the substantial potential of IR algorithms for overcoming traditional limitations in CT imaging

Automatic segmentation of the left ventricle cavity and myocardium in MRI data

A novel approach for the automatic segmentation has been developed to extract the epi-cardium and endo-cardium boundaries of the left ventricle (lv) of the heart. The developed segmentation scheme takes multi-slice and multi-phase magnetic resonance (MR) images of the heart, transversing the short-axis length from the base to the apex. Each image is taken at one instance in the heart's phase. The images are segmented using a diffusion-based filter followed by an unsupervised clustering technique and the resulting labels are checked to locate the (lv) cavity. From cardiac anatomy, the closest pool of blood to the lv cavity is the right ventricle cavity. The wall between these two blood-pools (interventricular septum) is measured to give an approximate thickness for the myocardium. This value is used when a radial search is performed on a gradient image to find appropriate robust segments of the epi-cardium boundary. The robust edge segments are then joined using a normal spline curve. Experimental results are presented with very encouraging qualitative and quantitative results and a comparison is made against the state-of-the art level-sets method

Sensor, Signal, and Imaging Informatics in 2017.

Objective To summarize significant contributions to sensor, signal, and imaging informatics literature published in 2017.Methods PubMed® and Web of Science® were searched to identify the scientific publications published in 2017 that addressed sensors, signals, and imaging in medical informatics. Fifteen papers were selected by consensus as candidate best papers. Each candidate article was reviewed by section editors and at least two other external reviewers. The final selection of the four best papers was conducted by the editorial board of the International Medical Informatics Association (IMIA) Yearbook.Results The selected papers of 2017 demonstrate the important scientific advances in management and analysis of sensor, signal, and imaging information.ConclusionThe growth of signal and imaging data and the increasing power of machine learning techniques have engendered new opportunities for research in medical informatics. This synopsis highlights cutting-edge contributions to the science of Sensor, Signal, and Imaging Informatics

Quantitative planar and volumetric cardiac measurements using 64 mdct and 3t mri vs. Standard 2d and m-mode echocardiography: does anesthetic protocol matter?

Cross‐sectional imaging of the heart utilizing computed tomography and magnetic resonance imaging (MRI) has been shown to be superior for the evaluation of cardiac morphology and systolic function in humans compared to echocardiography. The purpose of this prospective study was to test the effects of two different anesthetic protocols on cardiac measurements in 10 healthy beagle dogs using 64‐multidetector row computed tomographic angiography (64‐MDCTA), 3T magnetic resonance (MRI) and standard awake echocardiography. Both anesthetic protocols used propofol for induction and isoflourane for anesthetic maintenance. In addition, protocol A used midazolam/fentanyl and protocol B used dexmedetomedine as premedication and constant rate infusion during the procedure. Significant elevations in systolic and mean blood pressure were present when using protocol B. There was overall good agreement between the variables of cardiac size and systolic function generated from the MDCTA and MRI exams and no significant difference was found when comparing the variables acquired using either anesthetic protocol within each modality. Systolic function variables generated using 64‐MDCTA and 3T MRI were only able to predict the left ventricular end diastolic volume as measured during awake echocardiogram when using protocol B and 64‐MDCTA. For all other systolic function variables, prediction of awake echocardiographic results was not possible (P = 1). Planar variables acquired using MDCTA or MRI did not allow prediction of the corresponding measurements generated using echocardiography in the awake patients (P = 1). Future studies are needed to validate this approach in a more varied population and clinically affected dogs

Application of multidetector computed tomography in the diagnosis of pulmonary embolism and new directions of development

Introduction: Pulmonary embolism (PE) is a condition involving the mechanical part of the closure of the pulmonary arterial thrombus or other embolic material. Is the third the most typical cardiovascular disease - vascular, immediately after a heart attack and stroke. Clinical symptoms are often nonspecific and may result in an incorrect diagnosis. The most common complications of PE include: attack the lungs, impaired heart function, superinfection and development of pulmonary hypertension. Objective: The purpose of the work was to discuss of the technical aspects and the use of multi-slice computed tomography in the diagnosis of PE. The presentation emphasized new directions of development of tomographic methods in imaging thromboembolic events of pulmonary arteries, including multi-energy CT and low-dose techniques. Description of the state of knowledge: Angiography-CT is currently the gold standard in the diagnosis of PE, especially in patients with high and indirect clinical risk. It is characterized by high sensitivity and specificity in contrast enhancement imaging defects within the pulmonary vasculature and blood changes in the pulmonary parenchyma, which may accompany the EP. It also allows to assess the features of right heart overload in the course of massive PE or radiological symptoms associated with the development of chronic PE. Summary: Nowadays, the greatest challenges of CT diagnostics in PE are the improvement of image quality, minimization of artifacts and reduction of the radiation dose to which the patient is exposed. Effective diagnosis of PE is not only good quality CT imaging, but also the efficiency of the process of diagnosis. Hence the development of new applications of CT - called. computer aided diagnosis (CAD)

Радиомические характеристики текстурных изменений эпикардиальной жировой ткани при атеросклеротическом поражении коронарных артерий

Aim. To investigate the association of the radiomic characteristics of epicardial adipose tissue (EAT) on contrast-free computed tomography (CT) of the heart with the severity of obstructive coronary lesion and myocardial ischemia.Methods. The study included 68 patients with coronary heart disease (mean age of 63.5±9.4, 45 men and 23 women), and 15 patients (mean age 30±4.8; 14 men and 1 woman) without cardiovascular disease as a control group. All the patients underwent multispiral computed coronary angiography, coronary calcium scores (CCS) determination and stress myocardial perfusion scintigraphy. Radiomic characteristics of EAT (texture analysis by gradations of gray color) were determined on non-contrast computer tomogram images of the heart using 3D-Sliser software and the SliserRadiomics module (version 4.10.2). The obtained indicators were compared between a control and under the study groups as well as between subgroups of patients divided according to the degree of obstruction of the coronary arteries, the size of the perfusion defect, and the value of the CCS.Results. The comparative analysis of radiomic indicators of EAT between patients with coronary artery disease and the control group showed the presence of statistically significant differences between them. At the same time, the correlation analysis in the study group did not reveal any correlations between the radiomic parameters and the size of the perfusion defect, CCS or degree of stenosis of the lumen of the coronary arteries.Conclusion. The textural characteristics of EAT in patients with coronary heart disease differ from those in individuals without cardiovascular pathology. At the same time, these indicators are not associated with the severity of obstructive lesions of the coronary arteries, the value of the CCS, and the size of the perfusion defect according to scintigraphy.Цель. Исследовать ассоциацию радиомических характеристик эпикардиальной жировой ткани (ЭЖТ) на бесконтрастной компьютерной томографии (КТ) сердца с выраженностью обструктивного поражения коронарного русла и ишемии миокарда.Материалы и методы. В исследование ретроспективно включены 68 пациентов с ишемической болезнью сердца (ИБС) (средний возраст 63,5±9,4 года; 45 мужчин и 23 женщины), а также 15 лиц (средний возраст 30±4,8 года; 14 мужчин и 1 женщина) без сердечно-сосудистых заболеваний, составившие группу контроля. Всем обследуемым выполнены мультиспиральная компьютерная коронароангиография, определение индекса коронарного кальция, нагрузочная перфузионная сцинтиграфия миокарда. На бесконтрастных КТ-изображениях сердца определяли радиомические характеристики ЭЖТ (текстурный анализ по градациям серого цвета) с помощью программного обеспечения 3D-Sliser и модуля SliserRadiomics (версия 4.10.2). Полученные показатели сравнивали между группами исследования и контроля, а также в подгруппах больных, разделенных в зависимости от степени обструкции коронарных артерий, размера дефекта перфузии и значения индекса коронарного кальция.Результаты. Сравнительный анализ радиомических показателей ЭЖТ у пациентов с ИБС и группы контроля показал наличие статистически значимых различий. В то же время корреляционный анализ в группе исследования не продемонстрировал связи между радиомическими показателями и размером дефекта перфузии, индексом коронарного кальция, степенью стеноза просвета коронарных артерий.Заключение. Текстурные характеристики ЭЖТ у пациентов с ИБС отличаются от таковых у лиц без сердечно-сосудистой патологии. В то же время данные показатели не ассоциированы с выраженностью обструктивного поражения коронарных артерий, значением индекса коронарного кальция, а также размером дефекта перфузии по данным сцинтиграфии