RPS 1103 - Exploring cardiac imaging through quantitative MRI

Author Block: T. Richard, V. Nogues, T. Boulle, V. De Villedon De Naide, K. Narceau, B. Durand, S. Sridi, H. Cochet, A. Bustin; Bordeaux/FR
Purpose: Papillary muscle infarction (PMI) has been linked to significantly increased mortality, and is a source of ventricular arrhythmias and mitral regurgitation. Bright-blood LGE (PSIR) imaging is the clinical gold standard for myocardial fibrosis characterization. However, the limited contrast at the blood-scar interface makes PMI visualization often challenging. Black-blood LGE imaging overcomes this limitation by improving scar-to-blood contrast. Here, we aim to develop a novel co-registered joint bright- and black-blood LGE technology (SPOT) that could improve visual PMI detection (visu-PMI) , while allowing an automated PMI detection algorithm (auto-PMI).
Methods or Background: Short-axis 2D whole-heart PSIR and SPOT images were collected on a 1.5T Siemens Aera system under breath-hold 12min post gadolinium injection. Auto-PMI included image acquisition, statistics-based slice selection, left ventricular endocardium segmentation, blood pool preprocessing, and fibrosis detection. 198 patients participated to the study and were divided into an optimization dataset for auto-PMI parameters selection, and a testing dataset to evaluate visu-PMI and auto-PMI performances. Two radiologists assessed PMI on PSIR and SPOT images. A consensus reading was used as reference standard. Number of patients with PMI were compared. Sensitivity and accuracy of both sequences and auto-PMI were measured. Inter- and intra-observer reproducibility were reported.
Results or Findings: Radiologists detected significantly more PMI with SPOT (average increase: 30%). SPOT outperformed average PSIR sensitivity (93% vs. 75%) and accuracy (93% vs. 86%). Average inter- and intra- reproducibility increased with SPOT (79% vs. 74%, 97% vs. 88%). Auto-PMI outperformed PSIR sensitivity (87%), while the accuracy equaled the SPOT average (86%).
Conclusion: Co-registered joint bright- and black-blood SPOT imaging allows for improved PMI detection and opens a new door for automated PMI assessment.
Limitations: Further validation in larger cohort is warranted. Visu- and auto-PMI reliability depends mostly on contrast selection.
Funding for this study: This research was supported by funding from the French National Research Agency under grant agreement ANR-22-CPJ2-0009-01, and from the European Research Council (ERC) grant "SMHEART" under the European Union’s Horizon 2020 research and innovation programme (grant agreement No101076351).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Biomedical Research Ethics Committee and all participants provided informed consent for participation.

Author Block: A. A. Peters, K. Fischer, M. Hundertmark, C. Schaub, G. Bonanno, S. Schmitter, D. Günsch, C. Gräni, B. Jung; Bern/CH
Purpose: The purpose of this work was to: 1) establish an efficient workflow for additional 7T-specific static B1+ shimming procedure as short as possible, 2) investigate whether a single set of B1+ shim values calculated at the beginning of the exam provides reliable image quality over a region of interest (ROI), 3) investigate whether spatial resolution or field strength has an influence on volumetric and myocardial strain parameters.
Methods or Background: Ten healthy volunteers underwent cine imaging at 7T and 3T on the same day. The B1+ shimming process at 7T used relative B1+ maps to minimize the coefficient of variation (CV) within a ROI covering the heart, with the constraint to maximize excitation homogeneity. Image quality was assessed by two experienced readers using a 4-point Likert scale, and quantitative measures such as left and right ventricular volumes and strain parameters were evaluated.
Results or Findings: Results showed that B1+ shimming significantly improved homogeneity, reducing the CV from 61.5% to 23.3%, while increasing transmit efficiency. Image quality at 7T exhibited more inhomogeneities compared to 3T, but these did not impact the clinical assessment of myocardial function. Quantitative analysis revealed higher myocardial mass and smaller ventricular volumes at 7T, though these differences were minimal and insignificant regarding clincial assessment. Strain parameters were comparable between 3T and 7T.
Conclusion: In conclusion, this study demonstrates that a fast and efficient workflow for B1+ shimming at 7T can achieve diagnostic image quality and accurate functional analysis comparable to 3T MRI.
Limitations: - Small sample size
- Small number of readers
Funding for this study: Not applicable
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not applicable

Author Block: M. C. Halfmann¹, L. Van Der Meulen², M. W. Smulders², H. M. J. M. Nies², F. Prizen², C. Mihl², A. Varga-Szemes³, R. J. Holtackers², T. S. Emrich¹; ¹Mainz/DE, ²Maastricht/NL, ³Charleston, SC/US
Purpose: Cardiac MRI derived myocardial extracellular volume fraction (ECV) is a reproducible imaging biomarker for myocardial fibrosis. However, well-controlled evidence on the influence of the timing of the scan in relation to the contrast injection is scarce. Therefore, this study aimed to compare ECV measurements at different time points after contrast injection in a large animal infarct model.
Methods or Background: Cardiac MRI was performed at 1.5T while the animals were ventilated and under general anesthesia. Hematocrit levels were drawn directly prior to the scan. Native short-axis T1-maps of the left ventricle were acquired. 7 and 30 minutes following an iv-administration of 0.2 mg/kg gadobutrol, post-contrast T1-maps at identical slice locations were acquired. ECV was calculated for both global and separately for the infarcted and remote myocardium. Results were compared using Pearson’s correlation and paired sample Student’s t-tests.
Results or Findings: A total of 13 Yorkshire pigs with balloon catheter-induced myocardial infarction were included in this prospective study. However, 7 animals died before the MRI due to severe arrhythmias and two animals did not undergo the scan due to instability. Thus, MRI was successful in four pigs. Median time between infarction and cardiac MRI was 8 days [IQR 8–8]. While there was a strong correlation between measurements at both time points (r=0.94), ECV was significantly higher at 30 vs. 7 minutes (32.2±5.0% vs. 27.8±4.2%,P=.015). This was confirmed when assessing infarcted (56.9±11.4% vs. 43.7±9.1%,P=.018) and remote myocardium (28.4±2.8% vs. 25.5±3.2%,P=.010) separately.
Conclusion: Myocardial ECV by cardiac MRI significantly increases with increasing time after contrast injection in a large animal infarct model. A similar effect was observed in regions with only remote myocardium and only infarcted myocardium.
Limitations: The limitation of the study is the limited number of animals.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Animal handling complied with the Dutch Law on Animal Experimentation and the European Directive on the Protection of Animals used for Scientific Purposes (2010/63/EU). This study was approved by the Experimental Animal Committee of Maastricht University (DEC2016-002).

Author Block: N. Mcveigh¹, D. T. Ryan¹, F. Ryan², M. Ferre², J. Mccambridge², M. Ledwidge², K. Mcdonald², J. Dodd¹; ¹Dublin 4/IE, ²Dublin/IE
Purpose: Evaluate a novel cardiac MRI biomarker of diastolic dysfunction, CMRe', in pre-clinical patients at risk of heart failure(HF).
Methods or Background: 236patients from the PARABLE trial(NCT04687111) underwent CMR. Mitral annular relaxation velocity(CMRe’) was measured at four mitral annular anchor points and compared with feature tracking analysis of radial, circumferential and longitudinal diastolic strain rate and velocity as the gold-standard. Comparison were made with a control group of 25 age/gender-matched subjects. Comparisons were made with independent t-test, diagnostic accuracy was performed with receiver operator curve analysis and predictors of diastolic dysfunction were analysed using logistic regression.
Results or Findings: LAVimax, LVEDVi, LVESVi and cardiac mass all demonstrated significant increases between patient and control groups (p<0.001 for all). Peak diastolic longitudinal velocity was the only significant feature tracking variable that differed between groups (p<0.001). LAVimax did not correlate with any measured feature tracking parameter when adjusted for clinical, left ventricle and left atrial parameters. In similar multivariate analysis, CMRe’ correlated with diastolic radial, circumferential and longitudinal strains rates, as well as radial and longitudinal diastolic velocity measurements (p<0.001). It also correlated with echo e’ (r=0.195,p=0.0069), LV mass (r=-.18,p=0.008), LAVimax (r=-.18,p=0.008) and BNP (r=-0.30,p<0.0001).
LAVimax and total CMR e’ both exhibited high accuracy as independent predictors of diastolic dysfunction (AUC:0.89, 0.76,p<0.001 for both).

Combined model (LAVImax and CMR e’ total) predicted diastolic dysfunction with an AUC = 0.99. LAVimax, CMR e’ and peak diastolic longitudinal velocity were independent predictors of diastolic dysfunction (p<0.001 for all), adjusted for clinical and standard CMR parameters.
Conclusion: CMRe' is a precise imaging biomarker for ALVDD. Integrating LAVimax and CMRe' holds promise in optimizing CMR methodologies for identifying patients at risk of diastolic dysfunction.
Limitations: Lack of BNP and Echo markers for the control group.
Funding for this study: This trial was supported by the Health Research Board of the Government of
Ireland, the European Commission Framework Programme 7, the Heartbeat
Trust CLG, and Novartis (the manufacturer of sacubitril/valsartan). Under the
terms of the grant from Novartis, the study was an investigator-led, Heartbeat
Trust–sponsored clinical trial.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: SVUH Ethics Committee

Author Block: L. Zhu, J. He, S. Zhao, M. Lu; Beijing/CN
Purpose: To evaluate the association between right ventricular (RV) strain parameters derived from cardiac magnetic resonance feature tracking (CMR-FT) and adverse outcomes in patients with heart failure with preserved ejection fraction (HFpEF).
Methods or Background: Patients with HFpEF who underwent CMR examination from January 2010 to December 2018 were retrospectively enrolled. The primary endpoint was all-cause mortality.
Results or Findings: A total of 1019 consecutive patients with HFpEF (age 56.9 ± 12.3 years; 70% male) were enrolled in this study. During a median follow-up of 7.8 years, 103 (10.1%) patients reached the primary endpoint. In multivariable Cox regression analysis, both RV global longitudinal and circumferential strain were independent predictors of the primary endpoint (HRadj per 1% increase, 1.07 [95% CI: 1.02, 1.12; P = .005] and 1.13 [95% CI: 1.05, 1.21; P < .001], respectively). The full model based on clinical, conventional imaging, and RV strain variables for the primary endpoint improved the model discrimination (C-index = 0.794) compared with the baseline model based solely on clinical variables (C-index = 0.716) and the model incorporating clinical and conventional imaging variables (C-index = 0.760). In receiver operating characteristic analysis for the primary endpoint, the addition of CMR-specific variables including late gadolinium enhancement and FT RV strain yielded an improved area under the curve for the baseline models (all P < .001).
Conclusion: RV global longitudinal and circumferential strain derived from CMR-FT were independent predictors of adverse clinical outcomes in patients with HFpEF, providing incremental prognostic value over traditional clinical and CMR-derived risk markers.
Limitations: This was a single-center, retrospective study. Echocardiographic parameters, including E/e’, were excluded from the Cox regression analysis due to missing values exceeding 50%.
Funding for this study: The Beijing Natural Science Foundation (grant no. 7242110)
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the institution ethics review board of Fuwai Hospital.

Author Block: S. S. D. Dereli Bulut, S. N. Emir; Istanbul/TR
Purpose: Non-compaction cardiomyopathy (NCCMP) is an uncommon disorder marked by increased trabeculation of the ventricular wall and the existence of non-compacted myocardial regions. These anatomical alterations may hinder the ventricle's relaxing capacity. Following the preliminary evaluation by echocardiogram (TTE), cardiac magnetic resonance imaging (CMR) is conducted for an in-depth assessment. A non-compacted to compacted myocardium ratio (N/C) exceeding 2.3 substantiates the diagnosis. This study aims to assess individuals with NCCMP who underwent CMR for signs of diastolic dysfunction (DD) and to explore the correlation between disease severity and DD.
Methods or Background: This retrospective, single-center study comprised 82 patients initially diagnosed with NCCMP based on TTE data. Cardiac Magnetic Resonance imaging was conducted utilising a 1.5 Tesla MRI scanner (Avanto, Siemens). Morphological and functional evaluations including left ventricular (LV) and right ventricular (RV) volume quantifications, cardiac output (CO), ejection fraction (EF), LV mass, peak ejection rate (PER), and peak filling rate (PFR). Correlation analysis was performed among these metrics.
Results or Findings: A substantial relationship was seen between the elevated N/C ratio and both PER and PFR (p<0.05; r=0.31, r=0.21, respectively). A positive association was noted between the N/C ratio and variations in LV mass assessed during the average and end-diastolic phases (r=0.35, p<0.05). No significant link was seen between the N/C ratio and LV EF (p>0.05), and no additional significant relationships were detected.
Conclusion: The structural alterations in NCCMP may hinder ventricular relaxation, adversely impacting diastolic function, which can be accurately identified using CMR. Timely identification of DD is essential for enhancing patients' quality of life.
Limitations: The patient population was small, the study was planned retrospectively
Funding for this study: The authors declared that this study has received no financial support.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Ethics Committee of the University Hospital

Author Block: L. Zhu, J. Xu, H. Zhang, C. Cui, P. Sun, S. Zhao, M. Lu; Beijing/CN
Purpose: To examine the impact of formalin fixation on biventricular parameters derived from diffusion tensor cardiac magnetic resonance (CMR) in a miniature-swine model, using histological findings as the reference standard.
Methods or Background: High-resolution ex-vivo diffusion tensor CMR data of one healthy miniature-swine were acquired at baseline, and at 5- and 9-days after the fixation with 10% neutral buffered formalin. Diffusion tensor CMR parameters were estimated using the AHA 16-segment model for the left ventricular (LV) wall, and an 8-segment model for the right ventricular (RV) wall. Histology with hematoxylin and eosin staining was performed at 10 days following formalin fixation to assess helix angles (HA) and HA gradients.
Results or Findings: Diffusion tensor CMR data at baseline, and 5- and 9-days following formalin fixation were head-to-head analyzed. Subepicardial HAs became much more negative after fixation in both LV and RV walls, and endocardial HAs showed a positive increase, which led to a significant elevation in HA gradients. In the LV wall, mean diffusivity values were slightly reduced during the first 5 days of fixation, followed by a marked decrease over the subsequent 4 days; while in the RV wall, these values also reduced during the first 5 days of fixation but did not change significantly over the next 4 days. HAs derived from diffusion tensor CMR exhibited excellent consistencies with those assessed with histology, among which baseline HAs yielded the highest interclass correlation coefficient of 0.953.
Conclusion: Formalin fixation had an impact on both fiber orientations and diffusion properties derived from diffusion tensor CMR, and baseline fiber orientations assessed before fixation showed the best consistency with histology findings.
Limitations: This study requires larger sample sizes to enhance the robustness of the findings.
Funding for this study: The Beijing Natural Science Foundation (grant no. 7242110)
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethics approval was obtained from the Ethics Committee for Animal Study of Fuwai Hospital.

Author Block: T. Génisson¹, V. De Villedon De Naide¹, B. Durand¹, K. Narceau¹, J-D. Maes¹, P. Gut², H. Cochet¹, M. Stuber², A. Bustin¹; ¹Bordeaux/FR, ²Lausanne/CH
Purpose: Bright-blood sequences are used to retrieve heart anatomy information, while black-blood late gadolinium enhancement has shown promise for scar detection. However myocardial scar assessment, crucial for accurate patient prognostic, is time-consuming, operator-dependent and labor-intensive. Here, we propose an artificial intelligence-based method for automated scar segmentation on joint bright- and black-blood LGE (SPOT) images.
Methods or Background: A cohort of 70 patients (21% female, age range 28-81yo) with known or suspected ischemic heart disease was divided into a training (70%), validation (10%) and testing (20%) set. Breath-held short-axis 2D whole-heart single-shot co-registered bright- and black-blood SPOT, and reference phase-sensitive inversion recovery (PSIR) images were collected on a 1.5T (Siemens Aera) 12min post-contrast injection. An experienced radiologist manually performed scar segmentation on SPOT and PSIR images.
A transformer-based model automatically segmented left ventricular wall on SPOT bright-blood images and the contours were propagated onto black-blood images. Then, a U-net automatically segmented the scar within these contours.
Scar segmentation accuracy was assessed. Another experienced radiologist graded the scar segmentation clinical quality (Likert scale: 0=redo; 1=major adjustments; 2=minor adjustments; 3=no adjustments needed). Concordance between scar size assessed with manual PSIR and automated SPOT processing was evaluated. Scar segmentation times were recorded.
Results or Findings: Scar segmentation was automatically achieved on SPOT in 0.14s per slice, reaching a global Dice of 76.1%. Scar segmentations were rated 3 in 62%, 1 or 2 in 33% and 0 in only 5% of the cases. No significant differences between scar sizes were found when comparing with manual PSIR processing (P<0.05).
Conclusion: The proposed method allows for fast, accurate and automated scar segmentation on SPOT images, achieving clinical quality needed to better help guide therapy.
Limitations: Validation in larger cohort is warranted.
Funding for this study: This research was supported by funding from the French National Research Agency under grant agreement ANR-22-CPJ2-0009-01, and from the European Research Council (ERC) grant "SMHEART" under the European Union’s Horizon 2020 research and innovation programme (grant agreement No101076351).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Biomedical Research Ethics Committee and all participants provided informed consent for participation.

Author Block: C. G. Glessgen¹, T. Chitiboi², J. Wetzl², J-P. Vallee¹; ¹Geneva/CH, ²Erlangen/DE
Purpose: Accelerated cardiac MRI cine sequences are essential for real-time imaging and for patients unable to hold their breath but come with reduced spatial resolution. A comparison of strain measurements from high-resolution (HR) and low-resolution (LR) cine data is presented, using two strain methods: deformable registration analysis (DRA) and feature-tracking (FT).
Methods or Background: Twenty patients with normal cardiac MRI findings who underwent standard SSFP cines (HR; 0.8×0.8mm2) and compressed-sensing accelerated single-shot SSFP cines (LR; 2.4×2.4mm2) at 1.5 T were retrospectively analyzed. Breath-hold short-axis images were processed using DRA (TrufiStrain v2.4, Siemens Healthineers) and FT (cvi42 v6.1, Circle CVI). Global radial (GRS) and circumferential strain (GCS) were calculated for each image/software pair. Correlations between HR and LR images and between software were assessed using Pearson's R coefficient; concordance was evaluated using Bland-Altman analysis.
Results or Findings: GCS correlation between HR and LR was stronger for DRA (r = 0.93, p < 0.05) than for FT (r = 0.68, p < 0.05). GRS correlations were similar for DRA and FT (r = 0.63 and r = 0.65, respectively, p < 0.05). Bland-Altman analysis showed a mean GCS difference between HR and LR of 0.02 (LoA: -3.14 to 3.19) for DRA and -4.35 (LoA: -7.00 to -1.69) for FT; for GRS, a mean difference of 18.37 (LoA: 0.60 to 36.15) for DRA and 13.81 (LoA: 6.23 to 21.38) for FT.
Conclusion: Cardiac strain measurements from LR and HR cines are well correlated but exhibit significant limits of agreement, which should be considered in clinical practice. DRA showed superior correlation and narrower limits of agreement for GCS, while FT demonstrated narrower but significant limits for GRS.
Limitations: This pilot work is limited by its sample size and the absence of pathological data.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Waiver for informed consent (ID: 01574)

Author Block: M. Jiang, M. Lu; Beijing/CN
Purpose: To assess whether left ventricular (LV) global longitudinal strain (GLS), derived from cardiovascular magnetic resonance (CMR), is associated with (i) major heart failure (HF) events, and (ii) sudden cardiac death (SCD) in patients with non-dilated left ventricular cardiomyopathy (NDLVC).
Methods or Background: We conducted a retrospective observational cohort study of patients with NDLVC assessed by CMR, including feature-tracking to assess LV GLS and late gadolinium enhancement (LGE). Long-term adjudicated follow-up included (i) HF hospitalization, heart transplantation or HF death, and (ii) SCD or aborted SCD (aSCD).
Results or Findings: Of 386 patients with NDLVC (mean age 45 years, 258 men [66.8%], median LVEF 49% [46–54]) followed up for a median 6.2 years, 68 patients (17.6%) experienced HF events and 15 (3.9%) experienced SCD or aSCD. Following adjustment in a multivariable model, the presence of LGE and LV GLS predicted the HF events (HR 1.95; 95% CI 1.17-3.27; p=0.011 vs. per % HR 1.14, CI 1.07–1.22, p<0.001). However, LV GLS was not associated with SCD/aSCD, whereas LGE presence still was (unadjusted HR 5.36, 95% CI 1.20–23.99, p=0.028). LVEF was neither associated with HF events nor SCD/aSCD.
Conclusion: Multi-parametric CMR has utility for precision prognostic stratification of patients with NDLVC. LV GLS stratifies risk of progressive HF, while LGE stratifies both HF and SCD risk.
Limitations: T1 mapping and extracellular volume calculation, which were more sensitive in detecting subtle myocardial alteration and fibrosis, were not not performed systematically in patients. Additional investigations are required to assess the potential diagnostic and prognostic significance of mapping techniques within this particular context.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The Institutional Review Board approved this study, and written informed consent was waived due to the retrospective nature of the study.