Does magnetic resonance tagging detect an elevated torsion-to-shortening ratio indicating subendocardial contractile dysfunction in asymptomatic children with valvular aortic stenosis?
MR tagging reveals an elevated torsion-to-shortening ratio in asymptomatic children with valvular aortic stenosis, identifying subendocardial contractile dysfunction that is undetectable by conventional techniques.
Abstract Perfusion of left ventricular (LV) subendocardium in valvular aortic stenosis (AS) patients is impaired. It was expected that this may lead to a reduction of subendocardial fiber contraction and, consequently, to an increase of LV torsion per amount of ejection. Using MR tagging (MRT), it was investigated whether the torsion‐to‐shortening ratio (TSR) is elevated in valvular AS patients. Six asymptomatic children with valvular AS were investigated using echo Doppler, ECG, exercise test, and MRT. LV torsion and natural strain of the inner diameter were determined from measured tag displacements in two short‐axis slices of the LV. In all AS patients TSR was ∼40% increased (0.62 ± 0.04 rad; mean ± SD) as compared to pediatric (0.44 ± 0.08 rad; n = 5) and adult controls (0.46 ± 0.08 rad; n = 9), indicating subendocardial contractile dysfunction. With other techniques hitherto used this type of dysfunction could not be detected. Magn Reson Med 51:135–139, 2004. © 2003 Wiley‐Liss, Inc.
Delhaas et al. (2003) studied this question.
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