Incremental benefit in correlation with histology of native T1 mapping, partition coefficient and extracellular volume fraction in patients with aortic stenosis

Abstract Funding Acknowledgements The study was supported by Center for Cardiological Innovation Background Myocardial scar burden (focal fibrosis) is associated with poor response to cardiac resynchronization therapy (CRT), and should preferably be detected prior to device implantation. Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is considered reference standard for scar detection, but is not available in renal failure. Diffuse fibrosis is assessed by T1 mapping CMR with or without calculation of extracellular volume fraction (ECV). The method is vulnerable to partial volume effects, thus subendocardial tissue is most often not included in mapping analyses. Whether the contrast-free native T1mapping could replace LGE in the preoperative evaluation of patients referred for CRT is unknown. Purpose To investigate if native T1 mapping and calculation of ECV can adequately detect scar in patients referred for CRT. Methods Scar was quantified as percentage segmental LGE in 45 patients (age 65 ± 10 years, 71% male, QRS-width 165 ± 17ms) referred for CRT. In total 720 segments were analyzed, and LGE≥50% was considered transmural scar. T1-mapping before and after contrast agent injection was performed in all patients. ECV was calculated based on the ratio between tissue T1 relaxation change and blood T1 relaxation change after contrast agent injection, corrected for the haematocrit level. The agreement between native T1/ECV and scar was evaluated with receiver operating characteristic (ROC) curves with calculation of area under the curve (AUC) and 95% confidence interval (CI). Results LGE was present in 255 segments, 465 segments were without LGE. Average native T1 in segments with LGE was 1028 ± 88 ms, and 1040 ± 60 ms in segments without LGE (p = 0.16). The corresponding numbers for ECV were 38.7 ± 10.9% and 30.0 ± 4.7%, p < 0.001. Native T1 showed poor agreement to scar independent of scar size (AUC = 0.532, 95% CI 0.485-0.578 for scars of all sizes, and AUC = 0.572, 95% CI 0.495-0.650 for transmural scars). ECV, on the other hand, showed reasonable agreement with scar of all sizes (AUC = 0.777, 95% CI 0.739-0.815), and good agreement with transmural scars (AUC = 0.856, 95% CI 0.811-0.902). (Figure) Conclusion The contrast-free CMR technique T1 mapping does not adequately detect scars in patients referred for CRT. Adding post contrast T1 measurements and calculating ECV improves accuracy, especially for transmural scars. Future studies should investigate if diffuse fibrosis could be predictive of CRT response. Abstract P1585 Figure. Detection of transmural scars

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Native T1 mapping and extracellular volume fraction for differentiation of myocardial diseases from normal CMR controls in routine clinical practice

BMC Cardiovascular Disorders ◽

10.1186/s12872-021-02086-3 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Rawiwan Thongsongsang ◽

Thammarak Songsangjinda ◽

Prajak Tanapibunpon ◽

Rungroj Krittayaphong

Keyword(s):

T1 Mapping ◽

Volume Fraction ◽

Diagnostic Yield ◽

Interventricular Septum ◽

Extracellular Volume ◽

Extracellular Volume Fraction ◽

Left Ventricular ◽

Control Group ◽

Myocardial Disease ◽

Native T1

Abstract Background This study aimed to determine native T1 and extracellular volume fraction (ECV) in distinct types of myocardial disease, including amyloidosis, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), myocarditis and coronary artery disease (CAD), compared to controls. Methods We retrospectively enrolled patients with distinct types of myocardial disease, CAD patients, and control group (no known heart disease and negative CMR study) who underwent 3.0 Tesla CMR with routine T1 mapping. The region of interest (ROI) was drawn in the myocardium of the mid left ventricular (LV) short axis slice and at the interventricular septum of mid LV slice. ECV was calculated by actual hematocrit (Hct) and synthetic Hct. T1 mapping and ECV was compared between myocardial disease and controls, and between CAD and controls. Diagnostic yield and cut-off values were assessed. Results A total of 1188 patients were enrolled. The average T1 values in the control group were 1304 ± 42 ms at septum, and 1294 ± 37 ms at mid LV slice. The average T1 values in patients with myocardial disease and CAD were significantly higher than in controls (1441 ± 72, 1349 ± 59, 1345 ± 59, 1355 ± 56, and 1328 ± 54 ms for septum of amyloidosis, DCM, HCM, myocarditis, and CAD). Native T1 of the mid LV level and ECV at septum and mid LV with actual and synthetic Hct of patients with myocardial disease or CAD were significantly higher than in controls. Conclusions Although native T1 and ECV of patients with cardiomyopathy and CAD were significantly higher than controls, the values overlapped. The greatest clinical utilization was found for the amyloidosis group.

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T1 Mapping for Noninvasively Detecting Diffuse Fibrosis in Severe Aortic Stenosis

Journal of Medical Imaging and Health Informatics ◽

10.1166/jmihi.2020.3076 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1534-1539

Author(s):

Jiajun Xie ◽

Xuhua Jian ◽

Qiyang Lu ◽

Jinxiu Meng ◽

Yu-Hsiang Juan ◽

...

Keyword(s):

Aortic Stenosis ◽

Cardiac Mri ◽

T1 Mapping ◽

Volume Fraction ◽

Severe Aortic Stenosis ◽

Extracellular Volume ◽

Extracellular Volume Fraction ◽

Left Ventricular ◽

Diffuse Fibrosis ◽

Mapping Technique

Purpose: To evaluate myocardial diffuse fibrosis in severe aortic stenosis (SAS) with cardiac magnetic resonance imaging (MRI) T1 mapping technique. Methods: Twenty-seven SAS patients and 15 controls were enrolled and performed cardiac MRI. Left ventricular (LV) structure, function and T1-derived parameters were measured to compare between SAS group and the controls. Correlation between T1-derived parameters and the extent of histologic fibrosis was performed in 15 patients who underwent aortic valve replacement surgery and myocardial biopsy. Results: The SAS group had LV remodeling with ventricular dilatation, hypertrophy, and contractile dysfunction. The native T1 (1336.2±62.5 ms vs. 1277.6±40.7 ms, p = 0.002) and extracellular volume fraction (ECV%) (26.7±2.2% vs. 24.9±2.2%, p = 0.018) were elevated in the SAS in comparison to the controls. Only ECV and λ correlated with the extent of fibrosis as measured by histology. Conclusion: Cardiac MRI with T1 mapping provides a noninvasive approach to evaluate LV myocardial diffuse fibrosis in SAS.

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Real-time cardiovascular magnetic resonance T1 and extracellular volume fraction mapping for tissue characterisation in aortic stenosis

Journal of Cardiovascular Magnetic Resonance ◽

10.1186/s12968-020-00632-0 ◽

2020 ◽

Vol 22 (1) ◽

Cited By ~ 2

Author(s):

Sören J. Backhaus ◽

Torben Lange ◽

Bo Eric Beuthner ◽

Rodi Topci ◽

Xiaoqing Wang ◽

...

Keyword(s):

Cardiovascular Magnetic Resonance ◽

Magnetic Resonance ◽

Aortic Stenosis ◽

Real Time ◽

Volume Fraction ◽

Extracellular Volume ◽

Extracellular Volume Fraction ◽

Post Contrast ◽

Native T1 ◽

Matrix Volume

Abstract Background Myocardial fibrosis is a major determinant of outcome in aortic stenosis (AS). Novel fast real-time (RT) cardiovascular magnetic resonance (CMR) mapping techniques allow comprehensive quantification of fibrosis but have not yet been compared against standard techniques and histology. Methods Patients with severe AS underwent CMR before (n = 110) and left ventricular (LV) endomyocardial biopsy (n = 46) at transcatheter aortic valve replacement (TAVR). Midventricular short axis (SAX) native, post-contrast T1 and extracellular volume fraction (ECV) maps were generated using commercially available modified Look-Locker Inversion recovery (MOLLI) (native: 5(3)3, post-contrast: 4(1)3(1)2) and RT single-shot inversion recovery Fast Low-Angle Shot (FLASH) with radial undersampling. Focal late gadolinium enhancement was excluded from T1 and ECV regions of interest. ECV and LV mass were used to calculate LV matrix volumes. Variability and agreements were assessed between RT, MOLLI and histology using intraclass correlation coefficients, coefficients of variation and Bland Altman analyses. Results RT and MOLLI derived ECV were similar for midventricular SAX slice coverage (26.2 vs. 26.5, p = 0.073) and septal region of interest (26.2 vs. 26.5, p = 0.216). MOLLI native T1 time was in median 20 ms longer compared to RT (p < 0.001). Agreement between RT and MOLLI was best for ECV (ICC > 0.91), excellent for post-contrast T1 times (ICC > 0.81) and good for native T1 times (ICC > 0.62). Diffuse collagen volume fraction by biopsies was in median 7.8%. ECV (RT r = 0.345, p = 0.039; MOLLI r = 0.40, p = 0.010) and LV matrix volumes (RT r = 0.45, p = 0.005; MOLLI r = 0.43, p = 0.007) were the only parameters associated with histology. Conclusions RT mapping offers fast and sufficient ECV and LV matrix volume calculation in AS patients. ECV and LV matrix volume represent robust and universally comparable parameters with associations to histologically assessed fibrosis and may emerge as potential targets for clinical decision making.

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Prognostic value of myocardial extracellular volume fraction evaluation based on cardiac magnetic resonance T1 mapping with T1 long and short in hypertrophic cardiomyopathy

European Radiology ◽

10.1007/s00330-020-07650-7 ◽

2021 ◽

Author(s):

Yuancheng Li ◽

Xiuming Liu ◽

Fuyao Yang ◽

Jie Wang ◽

Yuanwei Xu ◽

...

Keyword(s):

Cardiac Magnetic Resonance ◽

Hypertrophic Cardiomyopathy ◽

Magnetic Resonance ◽

Prognostic Value ◽

T1 Mapping ◽

Volume Fraction ◽

Extracellular Volume ◽

Extracellular Volume Fraction

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T1 and T2 Mapping in Cardiology: “Mapping the Obscure Object of Desire”

Cardiology ◽

10.1159/000478901 ◽

2017 ◽

Vol 138 (4) ◽

pp. 207-217 ◽

Cited By ~ 26

Author(s):

Sophie Mavrogeni ◽

Dimitris Apostolou ◽

Panayiotis Argyriou ◽

Stella Velitsista ◽

Lilika Papa ◽

...

Keyword(s):

Heart Failure ◽

T1 Mapping ◽

Clinical Decision Making ◽

Volume Fraction ◽

T2 Mapping ◽

Extracellular Volume ◽

Diffuse Fibrosis ◽

Post Contrast ◽

Cardiac Amyloid ◽

Native T1

The increasing use of cardiovascular magnetic resonance (CMR) is based on its capability to perform biventricular function assessment and tissue characterization without radiation and with high reproducibility. The use of late gadolinium enhancement (LGE) gave the potential of non-invasive biopsy for fibrosis quantification. However, LGE is unable to detect diffuse myocardial disease. Native T1 mapping and extracellular volume fraction (ECV) provide knowledge about pathologies affecting both the myocardium and interstitium that is otherwise difficult to identify. Changes of myocardial native T1 reflect cardiac diseases (acute coronary syndromes, infarction, myocarditis, and diffuse fibrosis, all with high T1) and systemic diseases such as cardiac amyloid (high T1), Anderson-Fabry disease (low T1), and siderosis (low T1). The ECV, an index generated by native and post-contrast T1 mapping, measures the cellular and extracellular interstitial matrix (ECM) compartments. This myocyte-ECM dichotomy has important implications for identifying specific therapeutic targets of great value for heart failure treatment. On the other hand, T2 mapping is superior compared with myocardial T1 and ECM for assessing the activity of myocarditis in recent-onset heart failure. Although these indices can significantly affect the clinical decision making, multicentre studies and a community-wide approach (including MRI vendors, funding, software, contrast agent manufacturers, and clinicians) are still missing.

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