JCMR 2020; 22.46. Real-time cardiovascular magnetic resonance T1 and extracellular volume fraction mapping for tissue characterization in aortic stenosis-s12968-020-00632-0

s12968-020-00632-0

Pdf Summary

This study evaluated a fast real-time (RT) cardiovascular magnetic resonance (CMR) T1 mapping method in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement. The goal was to compare RT mapping with the standard MOLLI technique and with myocardial fibrosis measured by endomyocardial biopsy.<br /><br />A total of 110 patients had CMR, and 46 also had LV biopsies. RT and MOLLI produced very similar extracellular volume fraction (ECV) values, especially in the septal region, with excellent agreement for ECV and good-to-excellent agreement for post-contrast and native T1 values. RT native T1 values were slightly lower than MOLLI values, but the clinically important ECV measurements were comparable.<br /><br />Histology showed a median diffuse collagen volume fraction of 7.8%. Among all imaging parameters, only ECV and left ventricular matrix volume correlated significantly with histologically assessed diffuse fibrosis. Native T1 and total fibrosis measures did not correlate well with biopsy results.<br /><br />The authors conclude that RT mapping is a fast and practical method for measuring ECV and LV matrix volume in aortic stenosis. These measures are robust, reproducible, and associated with diffuse myocardial fibrosis, suggesting they may help guide clinical decision making and follow-up. RT imaging may be especially useful in patients who have difficulty with breath-holding or arrhythmias, because it requires only a short acquisition time.

Keywords

real-time CMR

T1 mapping

aortic stenosis

transcatheter aortic valve replacement

extracellular volume fraction

myocardial fibrosis

MOLLI

endomyocardial biopsy

left ventricular matrix volume

diffuse fibrosis