Phase mapping of radionuclide gated biventriculograms in patients with sustained ventricular tachycardia or Wolff-Parkinson-White syndrome

Cine-MR Fourier phase imaging for quantification of regional wall asynergy in patients with anterior myocardial infarction

PURPOSE

The aim of this study was to evaluate whether Fourier analysis of cine-MR could detect wall motion abnormalities in patients with myocardial infarction.

METHODS

Ten patients with anterior myocardial infarction (seven men and three women; mean age, 58 +/- 16 years) were compared with six control subjects (four men and two women; mean age, 49 +/- 24 years). Gradient echo cardiac cine-MR slices were transformed using a commercially available Fourier algorithm to obtain phase angles of endocardial segments. Mean phase angle and phase dispersion (i.e., SD around the mean) were calculated. Segmental wall motion was evaluated using a 16-segment model and correlated to Fourier phase analysis.

RESULTS

Mean phase angle and phase dispersion were increased in patients compared with control subjects (respectively, 191 degrees +/- 23 degrees vs. 161 degrees +/- 25 degrees, P < 0.0001 and 21 degrees +/- 10 degrees vs. 11 degrees +/- 8 degrees, P = 0.0007). Analysis of variance showed a significant increased dispersion on basal slices (P = 0.002) mostly due to flow-void and entry slice phenomenon.

CONCLUSIONS

Fourier phase analysis of cardiac cine-MR is feasible and allows the evaluation of ventricular asynergy on the basis of endocardial wall motion.

Correlations between cardiac imaging and electrophysiological studies: what is the state of the art?

Changes in ventricular activation produced by bundle branch block, pre-excitation, and ventricular tachycardia and pacing have been studied by various cardiac imaging modalities. We reviewed results of previously published and newly generated imaging data correlated with known or measured electrophysiological studies. Echocardiography has been demonstrated to grossly correlate with abnormal ventricular wall motion when activation sequence was altered. However, phase analysis of radionuclide and cine-computed tomography have provided detailed noninvasive activation data that correlated reasonably well with measured electrical activation sequence in both animals and man. Analysis of wall motion may not predict activation sequence when muscle is damaged or excessive translational movement of the heart occurs. Body surface mapping of electrical potentials has the capability to accurately but noninvasively register an electrical activation image of the heart that circumvents the problems of imaging contraction sequence. In the future, body surface potential mapping should be more widely used clinically and experimentally.