Regional assessment of left ventricular torsion by CMR tagging.
OBJECTIVE
To introduce a standardized method for calculation of left ventricular torsion by CMR tagging and to determine the accuracy of torsion analysis in regions using an analytical model.


METHODS
Torsion between base and apex, base and mid, and mid and apex levels was calculated using CSPAMM tagging and Harmonic Phase tracking. The accuracy of torsion analysis on a regional basis (circumferential segments and transmural layers) was analyzed using an analytical model of a deforming cylinder with a displaced axis of rotation (AoR). Regional peak torsion values from twelve healthy volunteers calculated by the described method were compared to literature.


RESULTS
The deviation from the analytical torsion per % AoR-displacement (of the radius) was 0.90 +/- 0.44% for the circumferential segments and only 0.05% for the transmural layers. In the subjects, circumferentially, anterolateral torsion was larger than inferior (12.4 +/- 3.9 degrees vs. 5.0 +/- 3.3 degrees , N.S.). Transmurally, endocardial torsion was smaller than epicardial (7.5 +/- 1.3 degrees vs. 8.0 +/- 1.5 degrees , p < 0.001).


CONCLUSIONS
Variability in the position of the AoR causes a large variability in torsion in circumferential segments. This effect was negligible for global torsion, and torsion calculated in transmural layers. Results were documented for the healthy human heart and are in agreement with data from literature.
Rüssel
Iris K
IK
Dept. of Physics and Medical Technology, Vrije Universiteit Medical Center, De Boelelaan 1118 1081 HV Amsterdam, the Netherlands. i.russel@vumc.nl
Götte
Marco J
MJ
Kuijer
Joost P
JP
Marcus
J Tim
JT
D000328:Adult; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D054159:Torsion, Mechanical; D016277:Ventricular Function, Left