A comprehensive assessment of a prototype high ratio antiscatter grid in interventional cardiology using experimental measurements and Monte Carlo simulations.

Objective. To assess the performance of a new antiscatter grid design in interventional cardiology for image quality improvement and dose reduction using experimental measurements and Monte Carlo (MC) simulation.Approach.Experimental measurements were performed on an angiography system, using a multi-layered tissue simulating composite phantom made from of poly(methyl methacrylate), aluminium and expanded polystyrene (2/0.2/0.7 cm). The total phantom thickness ranged from 20.3 cm to 40.6 cm. Four conditions were compared; (A) 105 cm source-image receptor distance (SID) without grid, (Bi) 105 cm SID with grid ratio (r) and strip density (N) (r15N80), (Bii) 120 cm SID without grid, and (Biii) 120 cm SID with high ratio grid (r29N80). The system efficiency (η), defined by the signal-to-noise ratio, was compared from theBconditions against caseA. These conditions were also simulated with MC techniques, allowing additional phantom compositions to be explored. Weighted image quality improvement factor (ηw(u)) was studied experimentally at a specific spatial frequency due to the SID change. Images were simulated with an anthropomorphic chest phantom for the different conditions, and the system efficiency was compared for the different anatomical regions.Main results.Good agreement was found between theηandηw(u) methods using both measured and simulated data, with average relative differences between 2%-11%. CaseBiiiprovided higherηvalues compared toA, andBifor thicknesses larger than 20.3 cm. In addition, caseBiiialso provided higherηvalues for high attenuating areas in the anthropomorphic phantom, such as behind the spine.Significance.The new antiscatter grid design provided higher system efficiency compared to the standard grid for the parameters explored in this work.

From a laboratory to the wearables: a review on history and evolution of electrocardiogram / Del laboratorio a la práctica: una revisión sobre la historia y evolución del electrocardiograma

The development of electrocardiography, one of the top scientific breakthroughs of the 20th century, occurred in the field of cardiology. The history of the ECG began long before its invention, with the advent of the study of electricity in the medical field. The idea of electrophysiology and Waller's initial recording of the ‘electrogram’ encouraged Willem Einthoven to develop new string galvanometers and turn this remarkable physiologic occurrence into a vital clinical recording tool. It has progressed from Einthoven's innovation to wearable technology. In the first part of the 20th century, a number of inventive people achieved a remarkable succession of discoveries and advancements that led to the development of the 12-lead ECG as we know it today. It went further than that. The evolution of science and technology over the years has allowed for continual development in terms of usefulness, ranging from five operators to one operator meant to record the ECG trace, and mobility, ranging from around 300 Kg to roughly around 1 Kg. Electrocardiographs in minimized form now exist thanks to the modern era of digitalization. We will go over the significant processes in the development of the ECG in this article. (AU)

El desarrollo de la electrocardiografía, uno de los principales avances científicos del siglo XX, se produjo en el campo de la cardiología. La historia del ECG comenzó mucho antes de su invención, con el advenimiento del estudio de la electricidad en el campo médico. La idea de la electrofisiología y el registro inicial del "electrograma" de Waller animó a Willem Einthoven a desarrollar nuevos galvanómetros de hilo y convertir este acontecimiento fisiológico notable en una herramienta de registro clínico vital. Ha progresado desde la innovación de Einthoven hasta la tecnología portátil. En la primera parte del siglo XX, varias personas ingeniosas lograron una notable sucesión de descubrimientos y avances que condujeron al desarrollo del ECG de 12 derivaciones tal como lo conocemos hoy. Fue más allá que eso. La evolución de la ciencia y la tecnología a lo largo de los años ha permitido un desarrollo continuo en términos de utilidad, que va desde cinco operadores a un operador destinado a registrar el trazo de ECG, y la movilidad, que va desde alrededor de 300 kg hasta aproximadamente 1 kg. Los electrocardiógrafos en forma minimizada ahora existen gracias a la era moderna de la digitalización. Repasaremos los procesos significativos en el desarrollo del ECG en este artículo. (AU)

3D iterative reconstruction can do so much more than reduce dose.

Recent advances in software and hardware for cardiac SPECT have the potential to revolutionize nuclear cardiology. It is easy to use these technologies to maintain the status quo and lower radiation dose, despite the fact there is very little evidence that lowering patient dose in already low dose imaging protocols confers any benefit to patients. Cardiac SPECT has tremendous potential for risk stratification, molecular tracers, and high temporal resolution management of patients with electrophysiological disorders. In addition, these new reconstruction techniques can offer spatial resolution that is comparable and sometimes even superior to PET. Lastly, recent research has also held out the potential for performing absolute blood flow qualification using SPECT instrumentation. As these new technologies become available, the goal should be to make images better and improve patient care first, then optimize the dose.

Using Flexible Curved Noncontact Active Electrodes to Monitor Long-Term Heart Rate Variability.

The purpose of this study is to utilize flexible curved noncontact active electrodes to develop a nonperception, long-term, and wireless heart rate monitoring system. This study also verified the functions and capabilities of the system and provided information on physiological parameters recorded during our tests. Our system was used in tandem with a commercially standard measurement system; both systems were used to measure ECG signals on 10 healthy subjects under the simulated home and office scenarios. We verified the R-peak measurement accuracy of our system and used T-tests to analyze the data collected by both systems; our system reached an average sensitivity value of 0.983 and an average positive predictive value of 0.991 over several different scenarios where R-peak measurements were also highly accurate. The R-R time intervals of our system were highly consistent with the standard system. The correlation coefficient calculated reached almost one, and the differences between the two systems mostly fell within the ±10 ms range. Further study of the HRV time-domain parameters under four different scenarios showed no significant differences in most HRV parameters compared to the measurements by the standard system. We also used our system to record long-term heart rate signals.

Balram Bhargava: catalysing innovation.

Balram Bhargava talks with Sophie Cousins about fostering affordable, need-driven innovation.

Catheter steering in interventional cardiology: Mechanical analysis and novel solution.

In recent years, steerable catheters have been developed to combat the effects of the dynamic cardiac environment. Mechanically actuated steerable catheters appear the most in the clinical setting; however, they are bound to a number of mechanical limitations. The aim of this research is to gain insight in these limitations and use this information to develop a new prototype of a catheter with increased steerability. The main limitations in mechanically steerable catheters are identified and analysed, after which requirements and solutions are defined to design a multi-steerable catheter. Finally, a prototype is built and a proof-of-concept test is carried out to analyse the steering functions. The mechanical analysis results in the identification of five limitations: (1) low torsion, (2) shaft shortening, (3) high unpredictable friction, (4) coupled tip-shaft movements, and (5) complex cardiac environment. Solutions are found to each of the limitations and result in the design of a novel multi-steerable catheter with four degrees of freedom. A prototype is developed which allows the dual-segmented tip to be steered over multiple planes and in multiple directions, allowing a range of complex motions including S-shaped curves and circular movements. A detailed analysis of limitations underlying mechanically steerable catheters has led to a new design for a multi-steerable catheter for complex cardiac interventions. The four integrated degrees of freedom provide a high variability of tip directions, and repetition of the bending angle is relatively simple and reliable. The ability to steer inside the heart with a variety of complex shaped curves may potentially change conventional approaches in interventional cardiology towards more patient-specific and lower complexity procedures. Future directions are headed towards further design optimizations and the experimental validation of the prototype.

The association of imaging equipment age with other quality metrics and successful laboratory accreditation by the Intersocietal Accreditation Commission.

BACKGROUND: Intersocietal Accreditation Commission (IAC) accreditation is granted or delayed depending on the fulfillment of several quality metrics. Investing in up-to-date equipment might reflect a commitment to quality. METHODS: Data from echocardiography (n = 3079) and nuclear cardiology (n = 1835) accreditation applications submitted between 2012 and 2014 were evaluated to determine the mean age of laboratory equipment. Laboratory quality was assessed by the number of missing quality metrics, and a composite quality score was calculated as the sum of missing quality metrics. A lower score thus represented better laboratory quality. The relationship between equipment age and quality was explored as an interaction term between equipment age and the composite quality score and was incorporated into regression models for prediction of accreditation status. RESULTS: During the study period, 49% of echocardiography and 42% of nuclear laboratories were granted accreditation without delay. For both echocardiography and nuclear laboratories, there was a statistically significant trend toward an increasing number of missing quality metrics with increasing quartiles of equipment age. The interaction between equipment age and the composite quality score was a significant predictor of delay of accreditation for both echocardiography and nuclear cardiology laboratories, with a stronger association for 1st-time applicants. Among sites applying for accreditation in both modalities simultaneously, accreditation in one modality predicted the accreditation decision for the other. CONCLUSIONS: Laboratory quality is an important determinant of IAC accreditation, and equipment age is an effect modifier of this relationship. Contemporary equipment likely reflects a commitment to quality, for both echocardiography and nuclear laboratories.

Smartphone-Based Device in Exotic Pet Medicine.

This article reviews the use of the smartphone in exotic pet medicine. The mobile app is the most instinctive use of the smartphone; however, there are very limited software dedicated to the exotic pet specifically. With an adapter, the smartphone can be attached to a regular endoscope and acts as a small endoscopic unit. Additional devices, such as infrared thermography or ultrasound, can be connected to the smartphone through the micro-USB port. The medical use of the smartphone is still in its infancy in veterinary medicine but can bring several solutions to the exotic pet practitioner and improve point-of-care evaluation.

Evaluating the Performance of Cardiac Pulse Duplicators Through the Concept of Fidelity.

INTRODUCTION: The advanced design techniques used in modern prosthetic heart valve (PHV) development require accurate replication of the entire cardiac cycle. While cardiac pulse duplicator (CPD) design has a direct impact on the PHV test data generated, no clear guidelines exist to evaluate the CPD's performance. In response to this, we present a method to quantitatively assess CPD performance. MATERIALS AND METHODS: A method to establish the fidelity of CPDs was formulated based on the pressure/time relationship and the error related to this relationship's target. This method was applied to assess the performance of a custom-made CPD. The performance evaluation included the assessment of the motion control system and overall repeatability of pressure measurements using a St Jude Epic 21 mm aortic valve. RESULTS: The CPD's motion control system had an average root mean square error (RMSE) beat-to-beat tracking accuracy of 0.046 ± 0.008 mm. Assessment of the pressure measurements yielded a repeatability of < 2.4 ± 0.9 mmHg RMSE beat-to-beat differential pressure. The combination of pressure and its location within a heartbeat (fidelity) was within 5.0% of the individual targets for at least 95% of heartbeats. CONCLUSION: Fidelity can be used to objectively quantify the performance of various aspects of CPDs and to identify the cause of unexpected PHV or CPD behaviour. It also enables comparisons to be made among various CPDs in terms of overall performance. This approach may enable standardization of the assessment of CPD performance in the future.

Advances in imaging instrumentation for nuclear cardiology.

Advances in imaging instrumentation and technology have greatly contributed to nuclear cardiology. Dedicated cardiac SPECT cameras incorporating novel, highly efficient detector, collimator, and system designs have emerged with the expansion of nuclear cardiology. Solid-state radiation detectors incorporating cadmium zinc telluride, which directly convert radiation to electrical signals and yield improved energy resolution and spatial resolution and enhanced count sensitivity geometries, are increasingly gaining favor as the detector of choice for application in dedicated cardiac SPECT systems. Additionally, hybrid imaging systems in which SPECT and PET are combined with X-ray CT are currently widely used, with PET/MRI hybrid systems having also been recently introduced. The improved quantitative SPECT/CT has the potential to measure the absolute quantification of myocardial blood flow and flow reserve. Rapid development of silicon photomultipliers leads to enhancement in PET image quality and count rates. In addition, the reduction of emission-transmission mismatch artifacts via application of accurate time-of-flight information, and cardiac motion de-blurring aided by anatomical images, are emerging techniques for further improvement of cardiac PET. This article reviews recent advances such as these in nuclear cardiology imaging instrumentation and technology, and the corresponding diagnostic benefits.

Systematic mapping study of data mining-based empirical studies in cardiology.

Data mining provides the methodology and technology to transform huge amount of data into useful information for decision making. It is a powerful process to extract knowledge and discover new patterns embedded in large data sets. Data mining has been increasingly used in medicine, particularly in cardiology. In fact, data mining applications can greatly benefits all parts involved in cardiology such as patients, cardiologists and nurses. This article aims to perform a systematic mapping study so as to analyze and synthesize empirical studies on the application of data mining techniques in cardiology. A total of 142 articles published between 2000 and 2015 were therefore selected, studied and analyzed according to the four following criteria: year and channel of publication, research type, medical task and empirical type. The results of this mapping study are discussed and a list of recommendations for researchers and cardiologists is provided.