Clinical Research
Cardiac Imaging
Measurement of Ventricular Torsion by Two-Dimensional Ultrasound Speckle Tracking Imaging

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Objectives

We sought to examine the accuracy/consistency of a novel ultrasound speckle tracking imaging (STI) method for left ventricular torsion (LVtor) measurement in comparison with tagged magnetic resonance imaging (MRI) (a time-domain method similar to STI) and Doppler tissue imaging (DTI) (a velocity-based approach).

Background

Left ventricular torsion from helically oriented myofibers is a key parameter of cardiac performance but is difficult to measure. Ultrasound STI is potentially suitable for measurement of angular motion because of its angle-independence.

Methods

We acquired basal and apical short-axis left ventricular (LV) images in 15 patients to estimate LVtor by STI and compare it with tagged MRI and DTI. Left ventricular torsion was defined as the net difference of LV rotation at the basal and apical planes. For the STI analysis, we used high-frame (104 ± 12 frames/s) second harmonic two-dimensional images.

Results

Data on 13 of 15 patients were usable for STI analysis, and LVtor profile estimated by STI strongly correlated with those by tagged MRI (y = 0.95x + 0.19, r = 0.93, p < 0.0001, analyzed by repeated-measures regression models). The STI torsional velocity profile also correlated well with that by the DTI method (y = 0.79x + 2.4, r = 0.76, p < 0.0001, by repeated-measures regression models) with acceptable bias.

Conclusions

The STI estimation of LVtor is concordant with those analyzed by tagged MRI (data derived from tissue displacement) and also showed good agreement with those by DTI (data derived from tissue velocity). Ultrasound STI is a promising new method to assess LV torsional deformation and may make the assessment more available in clinical and research cardiology.

Abbreviations and Acronyms

CV
coefficient of variation
DTI
Doppler tissue imaging
LV
left ventricular
LVrot
left ventricular rotation
LVrot-v
left ventricular rotational velocity
LVtor
left ventricular torsion
LVtor-v
left ventricular torsional velocity
MRI
magnetic resonance imaging
STI
speckle tracking imaging

Cited by (0)

Dr. Notomi is funded through a postdoctoral fellowship grant of the Ohio Valley affiliate of the American Heart Association (0325237B) and the current study is a part of the grant. This study also was supported in part by the National Aeronautics and Space Administration (Houston, Texas, Grant NCC9-58) and the Department of Defense (Fort Dietrich, Maryland, USAMRMC Grant #02360007).