Cardiovasc Imaging Asia.  2022 Jan;6(1):4-12. 10.22468/cvia.2021.00339.

Decelerated Dark Flow Measured Using Steady-State Free Precession Magnetic Resonance Imaging for Specific Detection of Left Ventricular Myocardial Strain and Dyssynchrony in Dilated Cardiomyopathy

• Kawakubo M
• Nagao M
• Nakao R
• Watanabe E
• Yoneyama M
• Hagiwara N
• Sakai S

• KMID: 2525205
• DOI: http://doi.org/10.22468/cvia.2021.00339

Abstract

Objective
In steady-state free precession (SSFP) cine imaging, signal loss can be observed as accelerated dark flow in patients with valvular disease and decelerated dark flow (DDF) in patients with severe left ventricular (LV) dysfunction. In our study, we measured DDF with optical flow calculations and investigated the relationship between DDF and myocardial strain or intraventricular dyssynchrony.
Materials and Methods
Fifty-seven consecutive patients with heart failure were retrospectively enrolled. In the short-axis orientation, the optical flow magnitude vector of the DDF was calculated over a cardiac cycle. The maximum value of the mean magnitude vector in the LV blood region was defined as the DDF index. The systolic circumferential strain (CS) of the LV free-wall, as well as the absolute difference in systolic timing of the LV free-wall and interventricular septum (LV dyssynchrony, LVD), was measured using the feature-tracking method. Spearman’s correlation coefficients (ρ) were calculated between DDF and CS or LVD.
Results
Median and interquartile ranges (25th to 75th percentile) of measured DDF, CS, and LVD in 57 patients were 14.0 (10.3 to 20.4), -8.0% (-13.3 to -3.2), and 40 ms (21 to 99), respectively. There were statistically significant correlations between the values of DDF and CS as well as LVD (0.60 and 0.48; p<0.01 for both).
Conclusion
Measurement of DDF may provide a specific clinical picture of myocardial strain and intraventricular dyssynchrony. Furthermore, it is possible to cost-effectively measure DDF without additional image acquisition during routine MR examination.

Keyword

Cine magnetic resonance imaging; Dilated cardiomyopathy; Heart ventricle; Medical image processing