Strain Imaging: assessment of myocardial mechanics
Strain: myocardial deformation (strain) can be assessed with this tool.
It can be obtained based on Tissue Doppler Imaging (TDI) or on bidimensional images (speckle tracking).
TDI allows better time definition and can be also used in case of poor echocardiographic windows.
Analyses from bidimensional images allow assessment of radial and circumferencial strain, as well as
apical and basal rotation, needed to calculate ventricular torsion. Normal values of
longitudinal LV deformation are between -20 to -25 %.
Strain rate: rate of myocardial deformation in time. Units are expressed in number/second
or %/second. Diastolic myocardial deformation can be assessed more clearly in this way.
Normal values of longitudinal LV deformation are 1 - 1.5/s or higher.
Here an extensive tutorial on this topic by
Dr. Asbjørn Støylen
- NTNU Trondheim, Norway.
ASE/EAE consensus statement on methodology and indications for the quantitative evaluation of
cardiac mechanics, 2011.
Normal strain:
values of myo- cardial deformation at systole lie here around -25 % on the lateral segments of the left
ventricle. Color encoded dynamic bidimen- sional image helps to visualize strain, red stands here for -20 %.
Pathological strain:
values of myocardial deformation at systole lie here around -7 %, being consequently very reduced. This case
is a proven myocardial invol- vement in systemic amyloidosis.
Normal strain rate:
values of diastolic myocardial deformation in this normal heart lie between 1.3 and 1.7/s.
Pathological strain rate:
this former amyloidosis case shows also a severe impairment of longitudinal diastolic myocardial
deformation, with values around 0.6/s.
Overview
