scholarly journals Temporal stability of gel relaxation-time phantoms for quality control of T1 and extracellular volume fraction measurements

2014 ◽  
Vol 16 (S1) ◽  
Author(s):  
Ee Ling Heng ◽  
Vassilis Vassiliou ◽  
Peter Gatehouse ◽  
Andreas Greiser ◽  
Shivraman Giri ◽  
...  
Keyword(s):  
Quality Control ◽  
Relaxation Time ◽  
Volume Fraction ◽  
Extracellular Volume ◽  
Temporal Stability ◽  
Extracellular Volume Fraction

scholarly journals Extracellular volume quantification using synthetic haematocrit assessed from native and post-contrast longitudinal relaxation T1 times of a blood pool

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lukas Opatril ◽  
Roman Panovsky ◽  
Jan Machal ◽  
Tomas Holecek ◽  
Lucia Masarova ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Volume Fraction ◽  
Extracellular Volume ◽  
Relaxation Times ◽  
Extracellular Volume Fraction ◽  
Blood Pool ◽  
Coefficient Of Determination ◽  
Post Contrast ◽  
T1 Relaxation ◽  
Before And After

Abstract Background In terms of cardiovascular magnetic resonance are haematocrit values required for calculation of extracellular volume fraction (ECV). Previously published studies have hypothesized that haematocrit could be calculated from T1 blood pool relaxation time, however only native T1 relaxation time values have been used and the resulting formulae had been both in reciprocal and linear proportion. The aim of the study was to generate a synthetic haematocrit formula from only native relaxation time values first, calculate whether linear or reciprocal model is more precise in haematocrit estimation and then determine whether adding post-contrast values further improve its precision. Methods One hundred thirty-nine subjects underwent CMR examination. Haematocrit was measured using standard laboratory methods. Afterwards T1 relaxation times before and after the application of a contrast agent were measured and a statistical relationship between these values was calculated. Results Different linear and reciprocal models were created to estimate the value of synthetic haematocrit and ECV. The highest coefficient of determination was observed in the combined reciprocal model “− 0.047 + (779/ blood native) − (11.36/ blood post-contrast)”. Conclusions This study provides more evidence that assessing synthetic haematocrit and synthetic ECV is feasible and statistically most accurate model to use is reciprocal. Adding post-contrast values to the calculation was proved to improve the precision of the formula statistically significantly.

scholarly journals Extracellular Volume Quantification using Synthetic Haematocrit Assessed from Native and Post-contrast Longitudinal Relaxation T1 Times of a Blood Pool

2021 ◽  
Author(s):  
Lukas Opatril ◽  
Roman Panovsky ◽  
Jan Machal ◽  
Tomas Holecek ◽  
Lucia Masarova ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Volume Fraction ◽  
Extracellular Volume ◽  
Relaxation Times ◽  
Extracellular Volume Fraction ◽  
Blood Pool ◽  
Coefficient Of Determination ◽  
Post Contrast ◽  
T1 Relaxation ◽  
Before And After

Abstract Background: In terms of cardiovascular magnetic resonance are haematocrit values required for calculation of extracellular volume fraction (ECV). Previously published studies have hypothesized that haematocrit could be calculated from T1 blood pool relaxation time, however only native T1 relaxation time values have been used and the resulting formulae had been both in reciprocal and linear proportion. The aim of the study was to generate a synthetic haematocrit formula from only native relaxation time values first, calculate whether linear or reciprocal model is more precise in haematocrit estimation and then determine whether adding post-contrast values further improve its precision.Methods: One hundred thirty-nine subjects underwent CMR examination. Haematocrit was measured using standard laboratory methods. Afterwards T1 relaxation times before and after the application of a contrast agent were measured and a statistical relationship between these values was calculated.Results: Different linear and reciprocal models were created to estimate the value of synthetic haematocrit and ECV. The highest coefficient of determination was observed in the combined reciprocal model “-0.047 + (779/ blood native) – (11.36/ blood post-contrast)”.Conclusions: This study provides more evidence that assessing synthetic haematocrit and synthetic ECV is feasible and statistically most accurate model to use is reciprocal. Adding post-contrast values to the calculation was proved to improve the precision of the formula statistically significantly.

Transmural heterogeneity of diffusion anisotropy in the sheep myocardium characterized by MR diffusion tensor imaging

2007 ◽  
Vol 293 (4) ◽  
pp. H2377-H2384 ◽  
Author(s):  
Yi Jiang ◽  
Julius M. Guccione ◽  
Mark B. Ratcliffe ◽  
Edward W. Hsu
Keyword(s):  
Diffusion Tensor Imaging ◽  
Volume Fraction ◽  
Diffusion Tensor ◽  
Extracellular Volume ◽  
Extracellular Volume Fraction ◽  
Left Ventricular ◽  
Fiber Direction ◽  
Significant Difference ◽  
Mr Diffusion ◽  
Mr Diffusion Tensor Imaging

The orientation of MRI-measured diffusion tensor in the myocardium has been directly correlated to the tissue fiber direction and widely characterized. However, the scalar anisotropy indexes have mostly been assumed to be uniform throughout the myocardial wall. The present study examines the fractional anisotropy (FA) as a function of transmural depth and circumferential and longitudinal locations in the normal sheep cardiac left ventricle. Results indicate that FA remains relatively constant from the epicardium to the midwall and then decreases (25.7%) steadily toward the endocardium. The decrease of FA corresponds to 7.9% and 12.9% increases in the secondary and tertiary diffusion tensor diffusivities, respectively. The transmural location of the FA transition coincides with the location where myocardial fibers run exactly circumferentially. There is also a significant difference in the midwall-endocardium FA slope between the septum and the posterior or lateral left ventricular free wall. These findings are consistent with the cellular microstructure from histological studies of the myocardium and suggest a role for MR diffusion tensor imaging in characterization of not only fiber orientation but, also, other tissue parameters, such as the extracellular volume fraction.

Abstract 17263: Pre-Clinical Left Ventricular Myocardial Remodeling in Patients With Friedreich’s Ataxia: A Cardiac MRI Study

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Karen A Takazaki1 ◽  
Thiago Quinaglia A. C. Silva ◽  
Alberto Martinez ◽  
Tomas Neilan ◽  
Ravi SHAH ◽  
...  
Keyword(s):  
Heart Failure ◽  
Volume Fraction ◽  
Extracellular Volume ◽  
Extracellular Volume Fraction ◽  
Friedreich’S Ataxia ◽  
Left Ventricular ◽  
Friedreich's Ataxia ◽  
Intracellular Water ◽  
Lv Mass ◽  
Burn Out

Background: Heart Failure (HF) is the most common cause of death in Friedreich’s ataxia (FRDA), an inherited mitochondrial disease. Myocardial fibrosis is a well-documented histopathological feature among FRDA patients with HF. Objectives: In this study we will investigate the myocardial extracellular volume fraction (ECV) and intracellular water lifetime (τ ic ), using T1-weighted CMR imaging, in a cohort of patients with FRDA without signs of heart failure. We will also investigate whether myocardial tissue phenotyping by CMR can highlight particular characteristics of LV remodeling in FRDA’s cardiomyopathy, beyond those currently assessed with imaging-based classification of disease severity. Methods: Twenty-six FRDA’s patients (age 26.6±9.3 years, 15 women) without signs of HF, and 10 healthy controls (32.6±7.3 years, 5 women) underwent cardiac magnetic resonance (CMR) studies for assessment of left ventricular (LV) function, myocardial T1, late gadolinium enhancement (LGE), extracellular volume fraction (ECV), and intracellular water-lifetime (τ ic ) as marker of cardiomyocyte size. Neurological decline was determined using the FRDA rating scale (FARS 3). Results: FRDA patients had normal LV ejection fraction (LVEF: 67.66±11.4 vs. 63.9±9.0, P=0.311), larger LV mass index (LVMASSi: 61.03±22.1 vs. 45±4.2g/m 2 , P<0.001), and decreased LV end-diastolic volume index (LVEDVi 53.42±12 vs. 75.7±16.1, P=0.002), compared with controls. ECV and τ ic , were increased in FRDA patients (ECV: 0.36±0.05 vs. 0.25±0.02, P<0.0001; τ ic : 0.13±0.07 vs. 0.06±0.03, P=0.001). ECV was positively associated with LV mass-to-volume ratio (r=0.628, P<0.001). FARS 3 correlated positively with disease duration (r=0.669, P<0.001), and negatively with τ ic , (r=0.478, P=0.039). LVMASSi and cardiomyocyte mass-index [(1–ECV)LVMASSi] declined with age, indicating that LV hypertrophy may transition to a “burn-out” phase with LV atrophy. Conclusions: LV hypertrophy in FRDA reflects an expansion of the myocardial interstitium and an increase in cardiomyocyte size. In contrast, the neurological decline was more likely with decreasing cardiomyocyte size, possibly an early sign of myocardial “burn-out” in FRDA.

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