Davide Piccini

Bio: Davide Piccini is an academic researcher from Siemens. The author has contributed to research in topics: Magnetic resonance angiography & Coronary arteries. The author has an hindex of 18, co-authored 79 publications receiving 1236 citations. Previous affiliations of Davide Piccini include University Hospital of Lausanne & University of Erlangen-Nuremberg.

Spiral Phyllotaxis: The Natural Way to Construct a 3D Radial Trajectory in MRI

Abstract: While radial 3D acquisition has been discussed in cardiac MRI for its excellent results with radial undersampling, the self-navigating properties of the trajectory need yet to be exploited. Hence, the radial trajectory has to be interleaved such that the first readout of every interleave starts at the top of the sphere, which represents the shell covering all readouts. If this is done sub-optimally, the image quality might be degraded by eddy current effects, and advanced density compensation is needed. In this work, an innovative 3D radial trajectory based on a natural spiral phyllotaxis pattern is introduced, which features optimized interleaving properties: (1) overall uniform readout distribution is preserved, which facilitates simple density compensation, and (2) if the number of interleaves is a Fibonacci number, the interleaves self-arrange such that eddy current effects are significantly reduced. These features were theoretically assessed in comparison with two variants of an interleaved Archimedean spiral pattern. Furthermore, the novel pattern was compared with one of the Archimedean spiral patterns, with identical density compensation, in phantom experiments. Navigator-gated whole-heart coronary imaging was performed in six healthy volunteers. High reduction of eddy current artifacts and overall improvement in image quality were achieved with the novel trajectory.

Respiratory self-navigation for whole-heart bright-blood coronary MRI: methods for robust isolation and automatic segmentation of the blood pool.

Abstract: Free-breathing three-dimensional whole-heart coronary MRI is a noninvasive alternative to X-ray coronary angiography. However, the existing navigator-gated approaches do not meet the requirements of clinical practice, as they perform with suboptimal accuracy and require prolonged acquisition times. Self-navigated techniques, applied to bright-blood imaging sequences, promise to detect the position of the blood pool directly in the readouts acquired for imaging. Hence, the respiratory displacement of the heart can be calculated and used for motion correction with high accuracy and 100% scan efficiency. However, additional bright signal from the chest wall, spine, arms, and liver can render the isolation of the blood pool impossible. In this work, an innovative method based on a targeted combination of the output signals of an anterior phased-array surface coil is implemented to efficiently suppress such additional bright signal. Furthermore, an algorithm for the automatic segmentation of the blood pool is proposed. Robust self-navigation is achieved by cross-correlation. These improvements were integrated into a three-dimensional radial whole-heart coronary MRI sequence and were compared with navigator-gated imaging in vivo. Self-navigation was successful in all cases and the acquisition time was reduced up to 63%. Equivalent or slightly superior image quality, vessel length, and sharpness were achieved. Magn Reson Med 000:000–000, 2011. © 2011 Wiley Periodicals, Inc.

Compressed sensing single-breath-hold CMR for fast quantification of LV function, volumes, and mass.

Abstract: Objectives The purpose of this study was to compare a novel compressed sensing (CS)–based single–breath-hold multislice magnetic resonance cine technique with the standard multi–breath-hold technique for the assessment of left ventricular (LV) volumes and function Background Cardiac magnetic resonance is generally accepted as the gold standard for LV volume and function assessment LV function is 1 of the most important cardiac parameters for diagnosis and the monitoring of treatment effects Recently, CS techniques have emerged as a means to accelerate data acquisition Methods The prototype CS cine sequence acquires 3 long-axis and 4 short-axis cine loops in 1 single breath-hold (temporal/spatial resolution: 30 ms/15 × 15 mm2; acceleration factor 110) to measure left ventricular ejection fraction (LVEFCS) as well as LV volumes and LV mass using LV model–based 4D software For comparison, a conventional stack of multi–breath-hold cine images was acquired (temporal/spatial resolution 40 ms/12 × 16 mm2) As a reference for the left ventricular stroke volume (LVSV), aortic flow was measured by phase-contrast acquisition Results In 94% of the 33 participants (12 volunteers: mean age 33 ± 7 years; 21 patients: mean age 63 ± 13 years with different LV pathologies), the image quality of the CS acquisitions was excellent LVEFCS and LVEFstandard were similar (485 ± 159% vs 498 ± 158%; p = 011; r = 096; slope 097; p Conclusions The results demonstrated the feasibility of applying the CS strategy to evaluate LV function and volumes with high accuracy in patients The single–breath-hold CS strategy has the potential to replace the multi–breath-hold standard cardiac magnetic resonance technique

5D whole-heart sparse MRI.

Abstract: Purpose A 5D whole-heart sparse imaging framework is proposed for simultaneous assessment of myocardial function and high-resolution cardiac and respiratory motion-resolved whole-heart anatomy in a single continuous noncontrast MR scan. Methods A non–electrocardiograph (ECG)-triggered 3D golden-angle radial balanced steady-state free precession sequence was used for data acquisition. The acquired 3D k-space data were sorted into a 5D dataset containing separated cardiac and respiratory dimensions using a self-extracted respiratory motion signal and a recorded ECG signal. Images were then reconstructed using XD-GRASP, a multidimensional compressed sensing technique exploiting correlations/sparsity along cardiac and respiratory dimensions. 5D whole-heart imaging was compared with respiratory motion-corrected 3D and 4D whole-heart imaging in nine volunteers for evaluation of the myocardium, great vessels, and coronary arteries. It was also compared with breath-held, ECG-gated 2D cardiac cine imaging for validation of cardiac function quantification. Results 5D whole-heart images received systematic higher quality scores in the myocardium, great vessels and coronary arteries. Quantitative coronary sharpness and length were always better for the 5D images. Good agreement was obtained for quantification of cardiac function compared with 2D cine imaging. Conclusion 5D whole-heart sparse imaging represents a robust and promising framework for simplified comprehensive cardiac MRI without the need for breath-hold and motion correction. Magn Reson Med 79:826–838, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Respiratory Self-navigated Postcontrast Whole-Heart Coronary MR Angiography: Initial Experience in Patients

Abstract: The results of this study demonstrate that respiratory self-navigated whole-heart coronary MR angiography is feasible in a patient setting and can easily be performed after contrast agent administration; its specificity for coronary artery disease detection in proximal branches is promising, while sensitivity needs to be improved.

Clinical recommendations for cardiovascular magnetic resonance mapping of T1, T2, T2 and extracellular volume: A consensus statement by the Society for Cardiovascular Magnetic Resonance (SCMR) endorsed by the European Association for Cardiovascular Imaging (EACVI)

Abstract: Parametric mapping techniques provide a non-invasive tool for quantifying tissue alterations in myocardial disease in those eligible for cardiovascular magnetic resonance (CMR). Parametric mapping with CMR now permits the routine spatial visualization and quantification of changes in myocardial composition based on changes in T1, T2, and T2*(star) relaxation times and extracellular volume (ECV). These changes include specific disease pathways related to mainly intracellular disturbances of the cardiomyocyte (e.g., iron overload, or glycosphingolipid accumulation in Anderson-Fabry disease); extracellular disturbances in the myocardial interstitium (e.g., myocardial fibrosis or cardiac amyloidosis from accumulation of collagen or amyloid proteins, respectively); or both (myocardial edema with increased intracellular and/or extracellular water). Parametric mapping promises improvements in patient care through advances in quantitative diagnostics, inter- and intra-patient comparability, and relatedly improvements in treatment. There is a multitude of technical approaches and potential applications. This document provides a summary of the existing evidence for the clinical value of parametric mapping in the heart as of mid 2017, and gives recommendations for practical use in different clinical scenarios for scientists, clinicians, and CMR manufacturers.

Prosthetic heart valve devices, prosthetic mitral valves and associated systems and methods

Abstract: Devices and methods for implantation at a native mitral valve having a non-circular annulus and leaflets. One embodiment of the device includes a valve support having a first region configured to be attached to a prosthetic valve with a plurality of prosthetic leaflets and a second region. The device can further include an anchoring member having a longitudinal dimension and including a first portion configured to contact tissue at the non-circular annulus, a second portion configured to be attached to the valve support, and a lateral portion between the first portion and the second portion. The second portion of the anchoring member is attached to the second region of the valve support while in a low-profile configuration in which the anchoring member and the valve support are configured to pass through vasculature of a human. The lateral portion is transverse to the longitudinal dimension. The anchoring member and the valve support are configured to move from the low-profile configuration to an expanded configuration in which the first portion of the anchoring member at least partially adapts to the non-circular annulus of the native mitral valve and the first region of the valve support is spaced inwardly from the first portion of the anchoring member relative to the longitudinal dimension of the anchoring member such that a shape of the first region of the valve support is at least partially independent of a shape of the first portion of the anchoring member.

A Study of the Motion and Deformation of the Heart due to Respiration

Abstract: This paper describes a quantitative assessment of respiratory motion of the heart and the construction of a model of respiratory motion. Three-dimensional magnetic resonance scans were acquired on eight normal volunteers and ten patients. The volunteers were imaged at multiple positions in the breathing cycle between full exhalation and full inhalation while holding their breath. The exhalation volume was segmented and used as a template to which the other volumes were registered using an intensity-based rigid registration algorithm followed by nonrigid registration. The patients were imaged at inhale and exhale only. The registration results were validated by visual assessment and consistency measurements indicating subvoxel registration accuracy. For all subjects, we assessed the nonrigid motion of the heart at the right coronary artery, right atrium, and left ventricle. We show that the rigid-body motion of the heart is primarily in the craniocaudal direction with smaller displacements in the right-left and anterior-posterior directions; this is in agreement with previous studies. Deformation was greatest for the free wall of the right atrium and the left ventricle; typical deformations were 3-4 mm with deformations of up to 7 mm observed in some subjects. Using the registration results, landmarks on the template surface were mapped to their correct positions through the breathing cycle. Principal component analysis produced a statistical model of the motion and deformation of the heart. We discuss how this model could be used to assist motion correction.

Prosthetic heart valve devices and associated systems and methods

Abstract: Prosthetic heart valve devices for percutaneous replacement of native heart valves and associated systems and method are disclosed herein. A prosthetic heart valve device configured in accordance with a particular embodiment of the present technology can include an expandable support having an outer surface and configured for placement between leaflets of the native valve. The device can also include a plurality of asymmetrically arranged arms coupled to the expandable support and configured to receive the leaflets of the native valve between the arms and the outer surface. In some embodiments, the arms can include tip portions for engaging a subannular surface of the native valve.

Compressed sensing for body MRI

Abstract: The introduction of compressed sensing for increasing imaging speed in magnetic resonance imaging (MRI) has raised significant interest among researchers and clinicians, and has initiated a large body of research across multiple clinical applications over the last decade. Compressed sensing aims to reconstruct unaliased images from fewer measurements than are traditionally required in MRI by exploiting image compressibility or sparsity. Moreover, appropriate combinations of compressed sensing with previously introduced fast imaging approaches, such as parallel imaging, have demonstrated further improved performance. The advent of compressed sensing marks the prelude to a new era of rapid MRI, where the focus of data acquisition has changed from sampling based on the nominal number of voxels and/or frames to sampling based on the desired information content. This article presents a brief overview of the application of compressed sensing techniques in body MRI, where imaging speed is crucial due to the presence of respiratory motion along with stringent constraints on spatial and temporal resolution. The first section provides an overview of the basic compressed sensing methodology, including the notion of sparsity, incoherence, and nonlinear reconstruction. The second section reviews state-of-the-art compressed sensing techniques that have been demonstrated for various clinical body MRI applications. In the final section, the article discusses current challenges and future opportunities. Level of Evidence: 5 J. Magn. Reson. Imaging 2017;45:966–987