Cardiac MR Elastography: Comparison with left ventricular pressure measurement

PURPOSE OF THE STUDYTo compare magnetic resonance elastography (MRE) with ventricular pressure changes in an animal model.MethodSThree pigs of different cardiac physiology (weight, 25 to 53 kg; heart rate, 61 to 93 bpm; left ventricular [LV] end-diastolic volume, 35 to 70 ml) were subjected to invasive LV pressure measurement by catheter and noninvasive cardiac MRE. Cardiac MRE was performed in a short-axis view of the heart and applying a 48.3-Hz shear-wave stimulus.

Relative changes in LV-shear wave amplitudes during the cardiac cycle were analyzed. Correlation coefficients between wave amplitudes and LV pressure as well as between wave amplitudes and LV diameter were determined.

Results: A relationship between MRE and LV pressure was observed in all three animals (R-square [greater than or equal to] 0.76).

No correlation was observed between MRE and LV diameter (R-square [less than or equal to] 0.15). Instead, shear wave amplitudes decreased 102 +/- 58 ms earlier than LV diameters at systole and amplitudes increased 175 +/- 40 ms before LV dilatation at diastole.

Amplitude ratios between diastole and systole ranged from 2.0 to 2.8, corresponding to LV pressure differences of 60 to 73 mmHg.

Conclusion: Externally induced shear waves provide information reflecting intraventricular pressure changes which, if substantiated in further experiments, has potential to make cardiac MRE a unique noninvasive imaging modality for measuring pressure-volume function of the heart.

Author: Thomas ElgetiMichael LauleNikola KaufelsJorg SchnorrBernd HammAbbas SamaniJurgen BraunIngolf Sack
Credits/Source: Journal of Cardiovascular Magnetic Resonance 2009, 11:44

Published on: 2009-11-09

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