Periodic Reporting for period 1 - SMHEART (Smart Cardiac Magnetic Resonance Delivering One-Click and Comprehensive Assessment of Cardiovascular Diseases)
Período documentado: 2023-09-01 hasta 2026-02-28
In the pursuit of understanding and treating CVD, cardiac magnetic resonance imaging (CMR) has remained the only modality capable of providing a comprehensive assessment of the heart’s function and structure without harmful radiation. Unfortunately, current CMR systems remain too slow, too complex, require highly trained specialists and, as such, have presented a barrier to a wider adoption of CMR.
The aim of this ERC project is to unleash the full potential of CMR to transform patient trajectories by introducing a fast, one-click, fully automated, and comprehensive imaging pipeline applicable to diagnosis, prognosis, and therapy selection in cardiology.
This aim will be achieved by (i) creating a novel imaging technology that collects CMR data in a single continuous free-breathing scan, taking into account post-processing requirements at the very origin of CMR sequence design; (ii) exploiting the unique contrasts generated by this technology to automatically extract quantitative markers on cardiac anatomy, function, and tissue characteristics; and (iii) translating this transformative technology from a pre-clinical to a clinical setting.
This will be the first-ever integrated cardiac imaging pipeline in which CMR images are acquired in a single click, jointly represented in a single volume, and automatically analysed. This will unlock obstacles for broader acceptance of CMR and unleash the full potential of CMR to maximize its impact on patient trajectories. The results of this project will pave the way towards robust image-based strategies for personalized patient care (diagnosis, risk stratification, therapy selection, monitoring, and image-guided interventions).
Here, three major obstacles to be overcome include time inefficiency, operator dependency, and suboptimal image contrast. Limited time efficiency makes CMR examinations excessively long and costly, which translates into restricted information and patient discomfort due to repetitive breath-holds. Operator dependency, owing to CMR sequence selection, complex image planning, and patient interaction, affects the exam quality, precision, repeatability, accuracy, and the general diagnostic yield. Finally, suboptimal image contrast, particularly at the blood-scar interface, leads to ambiguity and makes the analysis of CMR images the most arduous step of CMR interpretation and the one associated with the longest learning curve.
Time inefficiency and Operator dependency: Push-button free-running CMR sequences help address both shortcomings. As they allow for ‘non-stop’ continuous data collection, examination time is abbreviated, meticulous scan planning no longer necessary, patient comfort enhanced, and time efficiency substantially increased. These techniques were initially built for coronary MR angiography and functional imaging. Combined with engineered magnetization pre-pulses (e.g. saturation, inversion), this milestone technology enables quantitative (i.e. objective interpretation by clinicians) assessment of the myocardial tissue.
Suboptimal image contrast: Bright-blood late gadolinium-enhanced (LGE) imaging is the current gold standard to assess myocardial injuries in patients. On LGE images, scar presence and distribution are the cornerstone of the etiological diagnosis of structural heart diseases, and the transmurality of scar (i.e. depth) is employed to assess myocardial viability in ischemic patients and predict the benefit of subsequent revascularization. Moreover, the burden and heterogeneity of scar on LGE images was shown to be a powerful predictor of ventricular arrhythmias, with the potential to significantly improve the primary prevention of sudden cardiac death with implantable cardioverter defibrillators. However, these clinical applications with direct impact on patient trajectories are all impaired by the poor contrast at the blood-scar interface, resulting in limited sensitivity to small scars, and limited robustness of scar quantification, as this heavily relies on accurate delineation of the endocardial border.
The articles published on the topic of image acquisition propose several solutions for:
- Limited time efficiency: Free-breathing 3D whole-heart imaging with 100% scan efficiency and advanced variable-density undersampling.
- Suboptimal image contrast: Black-blood scar imaging.
- Contrast-agent-free imaging: T1-rho mapping.
Challenges in CMR image analysis:
AI-based segmentation techniques are currently regarded as the gold standard for automated CMR analysis as they help support time efficiency, enable earlier detection of diseases, and improve diagnostic accuracy. In anatomical and functional imaging, convolutional neural networks (CNNs) enable highly accurate partition of the image into several meaningful areas based on which clinical CMR indices can be extracted, such as left and right ventricular volumes, ejection fraction, wall thickness, and myocardial mass.
In tissue characterization, existing state-of-the-art approaches for myocardial scar segmentation from bright-blood LGE (PSIR) images can be broadly categorized into automated (e.g. using clustering techniques, such as fuzzy c-means or super-pixel segmentation) or semi-automated (such as full-width at half-maximum) approaches, both requiring prior manual delineation of the left ventricular wall. Scar and wall segmentations are subsequently used to derive quantitative metrics (scar burden and transmurality) that may be directly employed to optimize patient management (decision to perform defibrillator implantation or revascularization). Although promising, these technologies require heavy operator expertise, are limited to 2-dimensional imaging, and the quantifications remain poorly reproducible, as the border between the scar and the blood pool remains poorly defined due to the lack of contrast on bright-blood images.
The articles published on the topic of image analysis propose several solutions for:
- MR operator dependency: fully automated TI-scout analysis.
- Radiologist dependency: fully automated T1 mapping analysis.
On the dissemination front, we have taken steps to safeguard our innovations by patenting our technologies. Additionally, we have made our imaging methods available through diverse platforms like C2P and WIPs, ensuring accessibility for fellow researchers and medical doctors.
On the supervision side, it is important to promote and ensure the future of our young talents as much as possible. I am today very fortunate to have built a team of ten multidisciplinary experts and hope the next generation of world-leading experts will emerge from this initiative in support of longevity and sustainability. My team is in the privileged position that our innovations can quickly be leveraged, applied, and modified both at LIRYC and Bordeaux Hospital, as platform compatibility does not exist as a hurdle.