New technical developments in cardiac CT: Anatomy, fractional flow reserve (FFR), and machine learning

2021 ◽  
pp. 145-158
Author(s):  
Stephan Achenbach ◽  
Jonathan Leipsic ◽  
James Min
Keyword(s):  
Cardiac Ct ◽  
Three Dimensional ◽  
Invasive Technique ◽  
Ct Scanner ◽  
Clinical Tool ◽  
Fractional Flow ◽  
Non Invasive ◽  
Technical Developments ◽  
Flow Reserve ◽  
Ct Technology

Computed tomography (CT), in the context of cardiac imaging, faces numerous challenges. The heart is a complex, three-dimensional organ, which moves very rapidly and has small dimensions. The coronary arteries, the main target of cardiac CT imaging, are especially difficult to visualize by any non-invasive technique. All the same, technology progress has made the use of CT for cardiac and coronary diagnosis possible. For selected applications, including ruling out coronary artery stenoses in low-risk individuals, CT has become a clinical tool. This chapter describes the progress of CT technology, from the first commercially available CT scanner that permitted visualization of the heart with high temporal and spatial resolution in the late 1980s, to today’s incarnations that utilize radiomics and artificial intelligence.

New technical developments in cardiac CT

2015 ◽  
pp. 99-106
Author(s):  
Stephan Achenbach
Keyword(s):  
Ct Angiography ◽  
Coronary Ct Angiography ◽  
Cardiac Ct ◽  
Three Dimensional ◽  
Invasive Technique ◽  
Clinical Tool ◽  
Non Invasive ◽  
Technical Developments ◽  
Coronary Ct ◽  
Luminal Narrowing

Computed tomography (CT), in the context of cardiac imaging, faces numerous challenges. The heart is a complex, three-dimensional organ, which moves very rapidly and has small dimensions. Especially the coronary arteries, the main target of cardiac CT imaging, are difficult to visualize by any non-invasive technique. Technology progress has made the use of CT for cardiac and coronary diagnosis possible. For selected applications, including ruling out coronary artery stenoses in low-risk individuals, CT has become a clinical tool. The technical progress of cardiac CT, and especially coronary CT angiography, is continuous and rapid. One major aim is to improve image quality and broaden the applicability of coronary CT angiography, while at the same time achieving lower radiation doses. The other major aim is to extract more than purely anatomic information out of the dataset and to complement the information in luminal narrowing with information on downstream ischaemia.

scholarly journals Non-invasive fractional flow reserve: a comparison of one-dimensional and three-dimensional mathematical modeling effectiveness

2020 ◽  
Vol 19 (2) ◽  
pp. 2303
Author(s):  
D. G. Gognieva ◽  
E. S. Pershina ◽  
Yu. O. Mitina ◽  
T. M. Gamilov ◽  
R. A. Pryamonosov ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Fractional Flow Reserve ◽  
Three Dimensional ◽  
Fractional Flow ◽  
One Dimensional ◽  
Non Invasive ◽  
Flow Reserve

Fractional Flow Reserve: Does a Cut-off Value add Value?

2016 ◽  
Vol 11 (1) ◽  
pp. 17
Author(s):  
Shah R Mohdnazri ◽  
◽  
◽  
◽  
Thomas R Keeble ◽  
...  
Keyword(s):  
Fractional Flow Reserve ◽  
Coronary Intervention ◽  
Grey Zone ◽  
Fractional Flow ◽  
Non Invasive ◽  
Invasive Test ◽  
Flow Reserve ◽  
A Value ◽  
Percutaneous Coronary ◽  
Value Add

Fractional flow reserve (FFR) has been shown to improve outcomes when used to guide percutaneous coronary intervention (PCI). There have been two proposed cut-off points for FFR. The first was derived by comparing FFR against a series of non-invasive tests, with a value of ≤0.75 shown to predict a positive ischaemia test. It was then shown in the DEFER study that a vessel FFR value of ≥0.75 was associated with safe deferral of PCI. During the validation phase, a ‘grey zone’ for FFR values of between 0.76 and 0.80 was demonstrated, where a positive non-invasive test may still occur, but sensitivity and specificity were sub-optimal. Clinical judgement was therefore advised for values in this range. The FAME studies then moved the FFR cut-off point to ≤0.80, with a view to predicting outcomes. The ≤0.80 cut-off point has been adopted into clinical practice guidelines, whereas the lower value of ≤0.75 is no longer widely used. Here, the authors discuss the data underpinning these cut-off values and the practical implications for their use when using FFR guidance in PCI.

Comparison of LBM and FVM in the estimation of LAD stenosis

2021 ◽  
pp. 095441192110169
Author(s):  
Jian Liu ◽  
Yong Yu ◽  
Chenqi Zhu ◽  
Yu Zhang
Keyword(s):  
Stokes Equations ◽  
Flow Simulation ◽  
Diagnostic Methods ◽  
Computational Time ◽  
Speed Ratio ◽  
Maximum Speed ◽  
Fractional Flow ◽  
Local Flow ◽  
Non Invasive ◽  
Flow Reserve

The finite volume method (FVM)-based computational fluid dynamics (CFD) technology has been applied in the non-invasive diagnosis of coronary artery stenosis. Nonetheless, FVM is a time-consuming process. In addition to FVM, the lattice Boltzmann method (LBM) is used in fluid flow simulation. Unlike FVM solving the Navier–Stokes equations, LBM directly solves the simplified Boltzmann equation, thus saving computational time. In this study, 12 patients with left anterior descending (LAD) stenosis, diagnosed by CTA, are analysed using FVM and LBM. The velocities, pressures, and wall shear stress (WSS) predicted using FVM and LBM for each patient is compared. In particular, the ratio of the average and maximum speed at the stenotic part characterising the degree of stenosis is compared. Finally, the golden standard of LAD stenosis, invasive fractional flow reserve (FFR), is applied to justify the simulation results. Our results show that LBM and FVM are consistent in blood flow simulation. In the region with a high degree of stenosis, the local flow patterns in those two solvers are slightly different, resulting in minor differences in local WSS estimation and blood speed ratio estimation. Notably, these differences do not result in an inconsistent estimation. Comparison with invasive FFR shows that, in most cases, the non-invasive diagnosis is consistent with FFR measurements. However, in some cases, the non-invasive diagnosis either underestimates or overestimates the degree of stenosis. This deviation is caused by the difference between physiological and simulation conditions that remains the biggest challenge faced by all CFD-based non-invasive diagnostic methods.

scholarly journals Non-invasive fractional flow reserve (FFRCT) in the evaluation of acute chest pain – Concepts and first experiences

2021 ◽  
Vol 138 ◽  
pp. 109633
Author(s):  
Andreas M. Fischer ◽  
Marly van Assen ◽  
U. Joseph Schoepf ◽  
Andrew J. Matuskowitz ◽  
Akos Varga-Szemes ◽  
...  
Keyword(s):  
Chest Pain ◽  
Fractional Flow Reserve ◽  
Acute Chest Pain ◽  
Fractional Flow ◽  
Non Invasive ◽  
Flow Reserve

scholarly journals Latest Advances in Cardiac CT

2020 ◽  
Vol 15 ◽  
Author(s):  
Thomas D Heseltine ◽  
Scott W Murray ◽  
Balazs Ruzsics ◽  
Michael Fisher
Keyword(s):  
Machine Learning ◽  
Fractional Flow Reserve ◽  
Cardiac Ct ◽  
Disease Risk ◽  
Clinical Care ◽  
Plaque Burden ◽  
Extensive Literature ◽  
Fractional Flow ◽  
Flow Reserve ◽  
Recent Advances

Recent rapid technological advancements in cardiac CT have improved image quality and reduced radiation exposure to patients. Furthermore, key insights from large cohort trials have helped delineate cardiovascular disease risk as a function of overall coronary plaque burden and the morphological appearance of individual plaques. The advent of CT-derived fractional flow reserve promises to establish an anatomical and functional test within one modality. Recent data examining the short-term impact of CT-derived fractional flow reserve on downstream care and clinical outcomes have been published. In addition, machine learning is a concept that is being increasingly applied to diagnostic medicine. Over the coming decade, machine learning will begin to be integrated into cardiac CT, and will potentially make a tangible difference to how this modality evolves. The authors have performed an extensive literature review and comprehensive analysis of the recent advances in cardiac CT. They review how recent advances currently impact on clinical care and potential future directions for this imaging modality.

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