Human non-contrast T1 values and correlation with histology in diffuse fibrosis

Abstract

BackgroundAortic stenosis (AS) leads to diffuse fibrosis in the myocardium, which is linked to adverse outcome. Myocardial T1 values change with tissue composition.ObjectiveTo test the hypothesis that our recently developed non-contrast cardiac magnetic resonance (CMR) T1 mapping sequence could identify myocardial fibrosis without contrast agent.Design, setting and patientsA prospective CMR non-contrast T1 mapping study of 109 patients with moderate and severe AS and 33 age- and gender-matched controls.MethodsCMR at 1.5 T, including non-contrast T1 mapping using a shortened modified Look–Locker inversion recovery sequence, was carried out. Biopsy samples for histological assessment of collagen volume fraction (CVF%) were obtained in 19 patients undergoing aortic valve replacement.ResultsThere was a significant correlation between T1 values and CVF% (r=0.65, p=0.002). Mean T1 values were significantly longer in all groups with severe AS (972±33 ms in severe asymptomatic, 1014±38 ms in severe symptomatic) than in normal controls (944±16 ms) (p<0.05). The strongest associations with T1 values were for aortic valve area (r=−0.40, p=0.001) and left ventricular mass index (LVMI) (r=0.36, p=0.008), and these were the only independent predictors on multivariate analysis.ConclusionsNon-contrast T1 values are increased in patients with severe AS and further increase in symptomatic compared with asymptomatic patients. T1 values lengthened with greater LVMI and correlated with the degree of biopsy-quantified fibrosis. This may provide a useful clinical assessment of diffuse myocardial fibrosis in the future.

Native T1 Relaxation Time and Extracellular Volume Fraction as Accurate Markers of Diffuse Myocardial Fibrosis in Heart Valve Disease – Comparison With Targeted Left Ventricular Myocardial Biopsy –

“…In contrast to previous studies, we did not observe a significant relationship between aortic valve area, symptomatic status and DMF. 31 This may be explained by the fact that the present study enrolled mainly patients with severe symptomatic AS, whereas the population of the study by Bull et al 31 also involved asymptomatic patients with moderate to severe AS. Several authors post-contrast administration showed high accuracy to identify patients with severe DMF.…”

“…Bull et al have shown a moderate but significant correlation between the native T1 relaxation time and DMF in 19 patients with severe symptomatic AS using the ShMOLLI (a shortened MOLLI) sequence with a 1.5-T scanner. 31 Lee et al have even shown a strong correlation between the native T1 relaxation time and DMF in 20 patients with severe AS using a 3-T scanner and the MOLLI sequence. 21 De Meester de Ravenstein et al 22 have shown the opposite result.…”

Cardiac Magnetic Resonance T1 Mapping in Cardiomyopathies

“…It demonstrated that the precontrast "native T1" has a linear correlation with the percentage of myocardial fibrosis as measured histologically on invasive myocardial biopsy. T1 times postcontrast administration (10-15 min) had an inverse linear relationship with collagen content in myocardial fibrosis subjects [8,21,22]. …”

Correlation of Electrocardiogram and Regional Cardiac Magnetic Resonance Imaging Findings in ST‐Elevation Myocardial Infarction: A Literature Review

“…46 T1 measures permit noninvasive detection of biologically and pathologically important processes related to excess water in edema, protein deposition, and other T1 altering substances such as lipid or iron in hemorrhage. [46][47][48][49][50] The ECV technique is sensitive to the distribution of the LV myocardium into its cellular and extracellular interstitial compartments. 47 Alterations in these compartments occurring from different physiologic and pathophysiologic biologic processes leading to fibrotic changes can be more easily detected with ECV than with LGE.…”