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In Vivo Cardiac Diffusion Imaging Without Motion-Compensation Leads to Unreasonably High Diffusivity [Letter]

Moulin, Kevin; Stoeck, Christian T; Axel, Leon; Broncano, Jordi; Croisille, Pierre; Dall'Armellina, Erica; Ennis, Daniel B; Ferreira, Pedro F; Gotschy, Alexander; Miro, Santiago; Schneider, Jurgen E; Scott, Andrew D; Sosnovik, David E; Teh, Irvin; Tous, Cyril; Tunnicliffe, Elizabeth M; Viallon, Magalie; Nguyen, Christopher
PMID: 37000010
ISSN: 1522-2586
CID: 5463452

Modeling of factors affecting late gadolinium enhancement kinetics in MRI of cardiac amyloid

Axel, Leon
BACKGROUND:Late gadolinium enhancement (LGE) is a valuable part of cardiac magnetic resonance imaging (CMR). In particular, inversion-recovery imaging of LGE, with nulling of the signal from reference areas of myocardium, can have a distinctive pattern in some patients with cardiac amyloid, including both diffuse (relatively faint) subendocardial LGE and a relatively dark appearance of the blood. However, the underlying reasons for this distinctive appearance have not previously been well investigated. Pharmacokinetic modeling of myocardial contrast enhancement kinetics can potentially provide insight into the mechanisms of the distinctive LGE appearance that can be seen in cardiac amyloid, as well as why it may be unreliable in some patients. METHODS:An interactive three-compartment pharmacokinetic model of the dynamics of myocardial contrast enhancement in CMR was implemented, and used to simulate LGE dynamics in normal, scar, and cardiac amyloid myocardium; the results were compared with previously published values. RESULTS:The three-compartment model is able to capture the qualitative features of LGE, in patients with cardiac amyloid. In particular, the characteristic "dark blood" appearance of PSIR images of LGE in cardiac amyloid is seen to likely primarily reflect expansion of the extravascular extracellular space (EES) by amyloid in the "reference" myocardium; the cardiac amyloid contrast enhancement dynamics also reflect expansion of the body EES. CONCLUSION:The distinctive appearance of LGE in cardiac amyloid is likely due to a combination of diffuse expansion by amyloid of the EES of the reference myocardium and of the body EES.
PMCID:10413700
PMID: 37563646
ISSN: 1532-429x
CID: 5595312

Weight loss in hypertrophic cardiomyopathy: A clinical case series

Reuter, Maria C.; Massera, Daniele; Axel, Leon; Latson, Larry A.; Goldstein, Jonathan M.; Stepanovic, Alexandra; Sherrid, Mark V.
Background: Obesity is prevalent among patients with hypertrophic cardiomyopathy (HCM). Obese HCM patients have greater wall thickness, LV mass, worse hemodynamic function and NYHA class. Weight loss may favorably influence the HCM phenotype. Case summary: We describe six patients with hypertrophic cardiomyopathy who lost weight through diet and lifestyle changes (n = 4) or bariatric surgery (n = 2). Radiographic imaging, with cardiac MRI or CT scan, was performed before and after their weight loss. There was a mean decrease in LV mass and indexed LV mass, and a mean numerical decrease in mean wall thickness in up to 14 out of 18 LV segments. There was also NYHA class reduction in symptoms. Discussion: In this case series, we have shown that substantial weight loss in HCM patients can be associated with a decrease in LV mass, wall thickness and improvement in symptoms. These observations indicate the potential for positive remodeling of the heart by weight loss. Prospective studies of the benefits of weight loss in HCM are needed.
SCOPUS:85149714036
ISSN: 2772-4875
CID: 5446552

Apical Aneurysms and Mid-Left Ventricular Obstruction in Hypertrophic Cardiomyopathy

Sherrid, Mark V; Bernard, Samuel; Tripathi, Nidhi; Patel, Yash; Modi, Vivek; Axel, Leon; Talebi, Soheila; Ghoshhajra, Brian B; Sanborn, Danita Y; Saric, Muhamed; Adlestein, Elizabeth; Alvarez, Isabel Castro; Xia, Yuhe; Swistel, Daniel G; Massera, Daniele; Fifer, Michael A; Kim, Bette
BACKGROUND:Apical left ventricular (LV) aneurysms in hypertrophic cardiomyopathy (HCM) are associated with adverse outcomes. The reported frequency of mid-LV obstruction has varied from 36% to 90%. OBJECTIVES/OBJECTIVE:The authors sought to ascertain the frequency of mid-LV obstruction in HCM apical aneurysms. METHODS:The authors analyzed echocardiographic and cardiac magnetic resonance examinations of patients with aneurysms from 3 dedicated programs and compared them with 63 normal controls and 47 controls with apical-mid HCM who did not have aneurysms (22 with increased LV systolic velocities). RESULTS:]; P = 0.004). Complete emptying occurs circumferentially around central PMs that contribute to obstruction. Late gadolinium enhancement was always brightest and the most transmural apical of, or at the level of, complete emptying. CONCLUSIONS:The great majority (95%) of patients in the continuum of apical aneurysms have associated mid-LV obstruction. Further research to investigate obstruction as a contributing cause to apical aneurysms is warranted.
PMID: 36681586
ISSN: 1876-7591
CID: 5419392

SequenceMorph: A Unified Unsupervised Learning Framework for Motion Tracking on Cardiac Image Sequences

Ye, Meng; Yang, Dong; Huang, Qiaoying; Kanski, Mikael; Axel, Leon; Metaxas, Dimitris N.
Modern medical imaging techniques, such as ultrasound (US) and cardiac magnetic resonance (MR) imaging, have enabled the evaluation of myocardial deformation directly from an image sequence. While many traditional cardiac motion tracking methods have been developed for the automated estimation of the myocardial wall deformation, they are not widely used in clinical diagnosis, due to their lack of accuracy and efficiency. In this paper, we propose a novel deep learning-based fully unsupervised method, SequenceMorph, for in vivo motion tracking in cardiac image sequences. In our method, we introduce the concept of motion decomposition and recomposition. We first estimate the inter-frame (INF) motion field between any two consecutive frames, by a bi-directional generative diffeomorphic registration neural network. Using this result, we then estimate the Lagrangian motion field between the reference frame and any other frame, through a differentiable composition layer. Our framework can be extended to incorporate another registration network, to further reduce the accumulated errors introduced in the INF motion tracking step, and to refine the Lagrangian motion estimation. By utilizing temporal information to perform reasonable estimations of spatio-temporal motion fields, this novel method provides a useful solution for image sequence motion tracking. Our method has been applied to US (echocardiographic) and cardiac MR (untagged and tagged cine) image sequences; the results show that SequenceMorph is significantly superior to conventional motion tracking methods, in terms of the cardiac motion tracking accuracy and inference efficiency. Code will be available at <uri>https://github.com/DeepTag/SequenceMorph</uri>.
SCOPUS:85148454200
ISSN: 0162-8828
CID: 5426032

Cardiac MRI of characteristic motion findings in right bundle branch block

Axel, Leon; Kanski, Mikael; Gomez, Geraldine Villasana; Gozansky, Elliott; Babb, James S.
While there have been many descriptions of characteristic motion findings in left bundle branch block (LBBB), there are few published descriptions of such findings in right bundle branch block (RBBB). The purpose of this study was to assess the frequency of particular regional motion findings in cardiac magnetic resonance imaging (CMR) studies of patients with RBBB, compared with normal subjects. We focused on three distinctive motion patterns that can be seen in RBBB during early systole: delayed apex-ward motion of the RV base, "reverse septal flash", and "basal bulge". The presence and relative magnitude of these findings were independently scored by four experienced observers, in 3-chamber and 4-chamber CMR cines, for both normal subjects and patients with RBBB. These motion patterns were found to be strongly associated with the presence of RBBB. While only moderately sensitive, they were quite specific for RBBB, when present. In particular, with ROC analysis, a combined feature set of the findings in the 4-chamber view had an area under the curve of 0.81.This previously undescribed set of RBBB-associated early-systolic regional motion features (delayed apex-ward motion of the RV base, "reverse septal flash", and "basal bulge") is strongly suggestive of RBBB when present, particularly in the 4-chamber view. Although here evaluated with CMR, it is also likely to be associated with RBBB when seen with other cardiac imaging modalities.
SCOPUS:85174925617
ISSN: 1569-5794
CID: 5616712

Correlation of MRI premature ventricular contraction activation pattern in bigeminy with electrophysiology study-confirmed site of origin

Axel, Leon; Bhatla, Puneet; Halpern, Dan; Magnani, Silvia; Stojanovska, Jadranka; Barbhaiya, Chirag
Although PVCs commonly lead to degraded cine cardiac MRI (CMR), patients with PVCs may have relatively sharp cine images of both normal and ectopic beats ("double beats") when the rhythm during CMR is ventricular bigeminy, and only one beat of the pair is detected for gating. MRI methods for directly imaging premature ventricular contractions (PVCs) are not yet widely available. Localization of PVC site of origin with images may be helpful in planning ablations. The contraction pattern of the PVCs in bigeminy provides a "natural experiment" for investigating the potential utility of PVC imaging for localization. The purpose of this study was to evaluate the correlation of the visually assessed site of the initial contraction of the ectopic beats with the site of origin found by electroanatomic mapping. Images from 7 of 86 consecutive patients who underwent CMR prior to PVC ablation were found to include clear cine images of bigeminy. The visually apparent site of origin of the ectopic contraction was determined by three experienced, blinded CMR readers and correlated with each other, and with PVC site of origin determined by 3D electroanatomic mapping during catheter ablation. Blinded ascertainment of visually apparent initial contraction pattern for PVC localization was within 2 wall segments of PVC origin by 3D electroanatomic mapping 76% of the time. Our data from patients with PVCs with clear images of the ectopic beats when in bigeminy provide proof-of-concept that CMR ectopic beat contraction patterns analysis may provide a novel method for localizing PVC origin prior to ablation procedures. Direct imaging of PVCs with use of newer cardiac imaging methods, even without the presence of bigeminy, may thus provide valuable data for procedural planning.
PMID: 36598692
ISSN: 1875-8312
CID: 5395092

A Tool to Integrate Electrophysiological Mapping for Cardiac Radioablation of Ventricular Tachycardia

Wang, Hesheng; Barbhaiya, Chirag R; Yuan, Ye; Barbee, David; Chen, Ting; Axel, Leon; Chinitz, Larry A; Evans, Andrew J; Byun, David J
PURPOSE/UNASSIGNED:Cardiac radioablation is an emerging therapy for recurrent ventricular tachycardia. Electrophysiology (EP) data, including electroanatomic maps (EAM) and electrocardiographic imaging (ECGI), provide crucial information for defining the arrhythmogenic target volume. The absence of standardized workflows and software tools to integrate the EP maps into a radiation planning system limits their use. This study developed a comprehensive software tool to enable efficient utilization of the mapping for cardiac radioablation treatment planning. METHODS AND MATERIALS/UNASSIGNED:After the scar area is outlined on the mapping surface, the tool extracts and extends the annotated patch into a closed surface and converts it into a structure set associated with the anatomic images. The tool then exports the structure set and the images as The Digital Imaging and Communications in Medicine Standard in Radiotherapy for a radiation treatment planning system to import. Overlapping the scar structure on simulation CT, a transmural target volume is delineated for treatment planning. RESULTS/UNASSIGNED:The tool has been used to transfer Ensite NavX EAM data into the Varian Eclipse treatment planning system in radioablation on 2 patients with ventricular tachycardia. The ECGI data from CardioInsight was retrospectively evaluated using the tool to derive the target volume for a patient with left ventricular assist device, showing volumetric matching with the clinically used target with a Dice coefficient of 0.71. CONCLUSIONS/UNASSIGNED:HeaRTmap smoothly fuses EP information from different mapping systems with simulation CT for accurate definition of radiation target volume. The efficient integration of EP data into treatment planning potentially facilitates the study and adoption of the technique.
PMCID:10320498
PMID: 37415904
ISSN: 2452-1094
CID: 5539402

Considerations for stress perfusion cardiac magnetic resonance imaging in patients with cardiac implantable electronic devices [Editorial]

Chyou, Janice Y; Axel, Leon
PMID: 35842797
ISSN: 1540-8167
CID: 5278752

Visualization and Analysis of Multidimensional Cardiovascular Magnetic Resonance Imaging: Challenges and Opportunities

Axel, Leon; Phan, Timothy S; Metaxas, Dimitris N
Recent advances in magnetic resonance imaging are enabling the efficient creation of high-dimensional, multiparametric images, containing a wealth of potential information about the structure and function of many organs, including the cardiovascular system. However, the sizes of these rich data sets are so large that they are outstripping our ability to adequately visualize and analyze them, thus limiting their clinical impact. While there are some intrinsic limitations of human perception and of conventional display devices which hamper our ability to effectively use these data, newer computational methods for handling the data may aid our ability to extract and visualize the salient components of these high-dimensional data sets.
PMCID:9289269
PMID: 35859582
ISSN: 2297-055x
CID: 5279222