scholarly journals Real-time cardiac magnetic resonance tissue characterisation for fibrosis assessment in aortic stenosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S.J Backhaus ◽  
T Lange ◽  
B.E Beuthner ◽  
R Topci ◽  
X Wang ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Real Time ◽  
Volume Fraction ◽  
Left Ventricular ◽  
Funding Source ◽  
Single Shot ◽  
Post Contrast ◽  
Native T1

Abstract Background Myocardial fibrosis is a major determinant of outcome in aortic stenosis (AS). Novel fast real-time (RT) cardiac magnetic resonance (CMR) mapping techniques allow comprehensive quantification of fibrosis but have not yet been adequately validated 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 native, post-contrast T1 and extracellular volume fraction (ECV) maps were generated using commercially available 5(3)3 MOLLI and RT single-shot inversion recovery fast low-angle shot (FLASH) with radial undersampling. 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 myocardium (26.2 vs. 26.5, p=0.073) and inter-ventricular septum (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 precise T1 and ECV assessments with similar agreement with histology as compared to conventional MOLLI techniques. Single-shot real time techniques may be advantageous in sicker patients prone to dyspnoea or arrhythmia. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): German Research Foundation

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

2020 ◽  
Vol 22 (1) ◽  
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.

Stratifying the prognostic capability of cardiovascular magnetic resonance in severe aortic stenosis: a machine learning approach

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Kwak ◽  
R Everett ◽  
T Ko ◽  
H Lee ◽  
W Lee ◽  
...  
Keyword(s):  
Machine Learning ◽  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Volume Fraction ◽  
Left Ventricular ◽  
Funding Source ◽  
Ventricular Ejection Fraction ◽  
Increased Risk ◽  
The Impact

Abstract Background Cardiovascular magnetic resonance (CMR) demonstrates promise in improving patient risk stratification in aortic stenosis (AS). We explored whether machine learning might provide further insights into the prognostic capability of CMR parameters. Methods Severe AS patients (n=440) undergoing AVR were prospectively enrolled across 10 international sites, and CMR performed prior to AVR. A machine learning prediction model using a random survival forest (RSF) was trained with 29 variables, including 13 CMR, 4 echocardiography, and 12 clinical parameters, using post-AVR mortality as an outcome. The impact of the important variables on the outcome (partial dependency) was examined. Results The most predictive CMR parameters in the RSF model were the extracellular volume fraction (ECV%), followed by right ventricular ejection fraction (RVEF), late gadolinium enhancement (LGE%), and indexed left ventricular end-diastolic volume (LVEDVi). Regarding the partial effects, the predicted mortality increased strongly once the ECV% exceeded 26.5% (Figure 1A). The LGE% was associated with an increased risk of mortality, which reached a plateau beyond the level of 2% (Figure 1C). There were U-shaped relationships between mortality and both RVEF and LVEDVi, with the lowest mortality seen at RVEF 70% and LVEDVi 68ml/m2 (Figure 1B, D). These trends of predicted outcomes by each variable were verified in the Kaplan-Meier curves and Cox analyses (Table). In both Cox and RSF models, the predictability was substantially increased when these four CMR parameters were added to conventional clinical risk factors. An AS-CMR risk score comprised of these four parameters presented a stepwise increase in mortality with increasing adverse CMR features (p&lt;0.001). Conclusions Our machine learning analysis using RSF has identified ECV%, RVEF, LGE%, and LVEDVi as key prognostic markers in severe AS with a nonlinear influence of each parameter on mortality post-AVR. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was supported by grants from the Korean Health Technology R & D Project, Ministry of Health, Welfare & Family Affairs, Republic of Korea (HI16C0225 and HI15C0399) and the National Institute for Health Research (NIHR) infrastructure at Leeds.

P598T1 mapping and myocardial extracellular volume assessed by cardiac magnetic resonance in diabetic patients with stable coronary artery disease

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
G A B Boros ◽  
W Hueb ◽  
P C Rezende ◽  
F F Ribas ◽  
A R Dallazen ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Extracellular Volume ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Diabetic Patients ◽  
Myocardial Tissue ◽  
Syntax Score ◽  
Post Contrast ◽  
Native T1

Abstract Background T1 mapping is a quantitative technique of cardiac magnetic resonance (CMR) increasingly used for characterization of the myocardium. Type 2 diabetes mellitus (T2DM) may impact myocardial tissue structure, however studies that assessed this association using non-invasive methods have conflicting results. Purpose We sought to compare the tissue characteristics of the non-infarcted myocardium of patients with and without diabetes with multivessel CAD. Methods Patients with stable multivessel CAD and preserved left ventricular ejection fraction (LVEF), included in the MASS V trial, underwent contrast-enhanced CMR before revascularization procedures. Patients were stratified according to the T2DM diagnosis at baseline. Values of myocardial native T1, post-contrast T1 and extracellular volume fraction (ECV) were compared between diabetic and non-diabetic patients. Only myocardial tissue without late gadolinium enhancement were assessed. Results Of 155 patients studied, 67 (43%) were diabetic and 88 (57%) non-diabetic. Baseline characteristics were similiar between groups (age 70±10 vs 69±11; 69% vs 68% males; LVEF 65±13 vs 67±9). Mean Syntax score was 21.2±8.5 and 20.4±8.5 (p=0.52) in diabetic and non-diabetic, respectively. Myocardial native T1 values showed no diference in diabetic and non-diabetic (1013±67.9 vs 1015±61.4, p=0.72). However, in diabetic patients values of post-contrast T1 were significantly lower (482.2±43.8 vs 499.4±47.2, p=0.024) and ECV were higher (29.62±6.61 vs 27.08. ± 4.22, p=0.004). Multivariable analyses adjusted for age, sex, BMI, hypertension and Syntax score showed no differences in the results. Figure1 Conclusion In this study, T2DM was associated with higher ECV and lower post-contrast T1 values in the myocardial tissue. These findings suggest an increase in the myocardial intersticial matrix in patients with diabetes and stable multivessel CAD.

Abstract 10378: Characterization of Changes in Cardiac Structure and Function in Mice Treated With Anthracyclines Using Serial Cardiac Magnetic Resonance Imaging

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Pedro V Staziaki ◽  
Hoshang Farhad ◽  
Otávio Coelho-Filho ◽  
Ravi V Shah ◽  
Richard N Mitchell ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Myocardial Fibrosis ◽  
Myocardial Edema ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Post Contrast ◽  
Cardiac Edema ◽  
Early Increase ◽  
Acute Increase

Introduction: Anthracyclines are a standard chemotherapeutic agent. However, the anthracyclines are associated with a late reduction in left ventricular ejection fraction (LVEF) and heart failure. Pathologically, anthracycline-induced cardiotoxicity (AIC) is characterized by the development of cardiac edema and fibrosis and cardiac magnetic resonance (CMR) is the gold-standard imaging technique for edema and fibrosis. Hypothesis: We hypothesized that a) cardiac edema and fibrosis would be detected by CMR after anthracyclines and b) edema and fibrosis would provide prognostic information. Methods: We performed a longitudinal CMR and histological study of 45 wild-type mice randomized to doxorubicin (DOX, n=30, 5 mg/kg/week for 5 weeks) or placebo (n=15). Measurements were performed at baseline, 5, 10, and 20 weeks after DOX or placebo. Measures of interest were LVEF, myocardial edema and fibrosis. Edema was assessed by T2 mapping, fibrosis by calculating the extracellular volume (ECV) from pre- and post-contrast T1 measurements. Results: In DOX-treated mice vs. placebo, myocardial edema at 5 weeks was increased (T2 values of 32±4 vs. 21±3 ms, P<0.05, Fig. A), while LVEF was unchanged. At 10 weeks, there was a reduction in LVEF (54±6 vs. 63±5% μL, P<0.05) and an increase in myocardial fibrosis (ECV of 0.34±0.03 vs. 0.27±0.03, P<0.05, Fig. B). There was a correlation between T2 measures and cardiac water weight (r=0.79, P=0.007, Fig. C) and between the ECV and histological myocardial fibrosis (r=0.90, P<0.001; Fig. D). Both the early increase in edema and the sub-acute increase in fibrosis predicted the late DOX-induced mortality (P<0.001, Fig. E and F). Conclusions: Our data suggest that, in mice, CMR can detect the early increase in edema and sub-acute increase in fibrosis after anthracyclines, that an increase in edema precedes a reduction in LVEF, that the increase in edema and fibrosis are linked and both are predictive of late animal mortality.

Comprehensive evaluation of structural and functional myocardial impairments in Becker muscular dystrophy using quantitative cardiac magnetic resonance imaging

2018 ◽  
Vol 20 (8) ◽  
pp. 906-915 ◽  
Author(s):  
Benjamin Marty ◽  
Raymond Gilles ◽  
Marcel Toussaint ◽  
Anthony Béhin ◽  
Tanya Stojkovic ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Muscular Dystrophy ◽  
Comprehensive Evaluation ◽  
Becker Muscular Dystrophy ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Functional Impairments ◽  
Ventricular Ejection Fraction ◽  
Native T1

Abstract Aims Becker muscular dystrophy (BMD) is a genetic neuromuscular disease characterized by an alteration of the dystrophin protein. Myocardial involvement is frequent, eventually progressing to a dilated cardiomyopathy, and represents the most common cause of death for this pathology. We performed a comprehensive evaluation of myocardial functional and structural alterations encountered in a large cohort of BMD patients using quantitative cardiac magnetic resonance (CMR) imaging. Methods and results Eighty-eight BMD patients and 26 age-matched volunteers underwent standard cine and tag imaging to assess myocardial function and dyssynchrony, while native T1, T2, and extracellular volume fraction (ECV) were measured for tissue characterization. The left ventricular ejection fraction (LV-EF) was significantly reduced in 26% of the BMD patients. Patients exhibited higher dyssynchrony index than controls (6.94 ± 3.17 vs. 5.09 ± 1.25, P = 0.005). Diastolic dyssynchrony also exists in patients where systolic function was normal. BMD subjects, compared with controls, had significantly higher native T1, T2, and ECV (1183 ± 60 ms vs. 1164 ± 22 ms, 47.5 ± 4.5 ms vs. 45.6 ± 3.4 ms, 0.282 ± 0.050 vs. 0.231 ± 0.027, respectively, P < 0.05). Native T1, T2, and ECV correlated with LV-EF (R = −0.79, −0.70, and −0.71, respectively, P < 0.001) and N-terminal-pro brain natriuretic peptide (R = 0.51, 0.58, and 0.44, respectively, P < 0.001). Conclusion Quantitative CMR represents a powerful tool to evaluate structural and functional impairments in the myocardium of BMD subjects. Native T1, T2, and ECV provided quantitative biomarkers related to inflammation and fibrosis, and could stratify disease severity.

scholarly journals Interaction between respiration and right versus left ventricular volumes at rest and during exercise: a real-time cardiac magnetic resonance study

2014 ◽  
Vol 306 (6) ◽  
pp. H816-H824 ◽  
Author(s):  
Guido Claessen ◽  
Piet Claus ◽  
Marion Delcroix ◽  
Jan Bogaert ◽  
Andre La Gerche ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Real Time ◽  
Valsalva Maneuver ◽  
Left Ventricular ◽  
Breath Holding ◽  
Exact Nature ◽  
Ventricular Volumes ◽  
Normal Breathing ◽  
Lv Volumes

Breathing-induced changes in intrathoracic pressures influence left ventricular (LV) and right ventricular (RV) volumes, the exact nature and extent of which have not previously been evaluated in humans. We sought to examine this “respiratory pump” using novel real-time cardiac magnetic resonance (CMR) imaging. Eight healthy subjects underwent serial multislice real-time CMR during normal breathing, breath holding, and the Valsalva maneuver. Subsequently, a separate cohort of nine subjects underwent real-time CMR at rest and during incremental exercise. LV and RV end-diastolic volume (EDV) and end-systolic volume (ESV) and diastolic and systolic eccentricity indexes were determined at peak inspiration and expiration. During normal breathing, inspiration resulted in an increase in RV volumes [RVEDV: +18 ± 8%, RVESV: +14 ± 12%, and RV stroke volume (SV): +21 ± 10%, P < 0.01] and an opposing decrease in LV volumes ( P < 0.0001 for interaction). During end-inspiratory breath holding, RV SV decreased by 9 ± 10% ( P = 0.046), whereas LV SV did not change. During the Valsalva maneuver, volumes decreased in both ventricles (RVEDV: −29 ± 11%, RVESV: −16 ± 14%, RV SV: −36 ± 14%, LVEDV: −22 ± 17%, and LV SV: −25 ± 17%, P < 0.01). The reciprocal effect of respiration on LV and RV volumes was maintained throughout exercise. The diastolic and systolic eccentricity indexes were greater during inspiration than during expiration, both at rest and during exercise ( P < 0.0001 for both). In conclusion, ventricular volumes oscillate with respiratory phase such that RV and LV volumes are maximal at peak inspiration and expiration, respectively. Thus, interpretation of RV versus LV volumes requires careful definition of the exact respiratory time point for proper interpretation, both at rest and during exercise.

Abstract 12586: Assessing Valvuloarterial Impedance in Aortic Stenosis: A Comparison of Echocardiographic- and Cardiac Magnetic Resonance-derived Methods

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Sara L Hungerford ◽  
Audrey Adji ◽  
Nicole K Bart ◽  
Linda Lin ◽  
Andrew Jabbour ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Flow Velocity ◽  
Cuff Pressure ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Applanation Tonometry ◽  
Aortic Flow ◽  
Entire Cross Section

Introduction: Valvuloarterial impedance (Z VA ) represents the valvular and arterial factors that oppose Left Ventricular (LV) ejection and is recognised as an important index to assess global LV load in patients with Aortic Stenosis (AS). Z VA is traditionally determined by Transthoracic Echocardiogram (TTE) and brachial cuff pressure. Hypothesis: Our study sought to compare Z VA-TTE with Z VA calculated using a simultaneous Cardiac Magnetic Resonance (CMR) and Applanation Tonometry (AT) (Z VA-CMR ) technique to determine whether TTE measurement of aortic flow velocity resulted in an underestimation of Z VA. Methods: Twenty AS patients underwent a protocol of CMR/AT followed by TTE. Z VA-CMR was determined as the relationship of derived aortic pressure (radial) to CMR aortic flow velocity in the frequency domain. Z VA-TTE was determined from digitised flow velocity within the left ventricular outflow tract (LVOT) on pulsed-wave Doppler and derived central pressure waveforms. Systemic vascular resistance (SVR) was calculated from mean pressure and flow. Values from both methods were compared. Results: Our study found that Z VA-TTE values (mean±SD, 638±381 dyne.s.cm -3 ) were consistently lower (p=0.07) than Z VA-CMR values (946±318 dyne.s.cm -3 ), and attribute this to an overestimation of LVOT flow velocity on TTE. SVR calculated by CMR/AT (2215±616 dyne.s.cm -5 ) was almost four times higher than TTE (618±245 dyne.s.cm -5 ) (p<0.001). This is due to more robust axi-symmetrical sampling of aortic flow across the entire cross-section of the ascending aorta (well above the stenotic jet) during CMR, than using operator-dependent TTE. Conclusions: Whilst Z VA -TTE is commonly performed in patients with AS to assess global LV load, newer methods to assess Z VA using simultaneous CMR/AT likely represent a more accurate non-invasive assessment.

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