Analysis of segmental and global function of the fetal heart using novel automatic functional imaging.
BACKGROUND
Functional assessment of the fetal heart has always been a challenge. Automatic functional imaging (AFI), a novel non-Doppler methodology based on 2-dimensional acoustic markers tracking, measures myocardial deformation regardless of angle of interrogation. Thus, we studied the validity of AFI in segmental and global assessment of myocardial function in the fetus.


METHODS
AFI-based myocardial deformation parameters including segmental tissue velocity, strain, and strain rate as well as biventricular global strain and strain rate were measured from raw scan-line data obtained from 28 normal fetuses (20-38, median 28 weeks of gestation). Interobserver and intraobserver variability was analyzed. AFI data were compared with analogous Doppler-derived tissue velocity imaging parameters measured in the same 28 fetuses.


RESULTS
AFI was feasible in 94% of the fetuses studied with high reproducibility. AFI-based tissue velocity (3.9 +/- 1 cm/s) was comparable with tissue velocity imaging-based velocity (4 +/- 1.6 cm/s) in the right ventricle and in the left ventricle (AFI velocity 3.3 +/- 0.6 vs tissue velocity imaging 3.1 +/- 0.9 cm/s). Strain rate obtained by these two methods was also similar. Biventricular global strain and strain rate measured 16 +/- 4% and 1.6 +/- .5 seconds(-1), respectively. Tissue velocity increased whereas segmental strain rate decreased throughout gestation. Strain remained unchanged. Global strain rate significantly decreased with gestational age (r = -0.7).


CONCLUSIONS
AFI, a novel non-Doppler methodology, allows fast and accurate quantification of segmental and global myocardial function in the fetus. AFI-based tissue velocity increases with gestational age whereas segmental and the new parameter global strain rate decrease throughout gestation.
Ta-Shma
Asaf
A
Division of Pediatric Cardiology, Hadassah University Medical Center, Jerusalem, Israel.
Perles
Zeev
Z
Gavri
Sagui
S
Golender
Julius
J
Tarshansky
Shulamit
S
Shlichter
Chava
C
Bar Tov
Hadassah
H
Rein
Azaria J J T
AJ
D001331:Automation; D015331:Cohort Studies; D018618:Echocardiography, Doppler, Color / Q000379:methods*; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging* / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009200:Myocardial Contraction / Q000502:physiology; D015588:Observer Variation; D011247:Pregnancy; D012016:Reference Values; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology*; D016216:Ultrasonography, Prenatal; D016277:Ventricular Function, Left / Q000502:physiology; D016278:Ventricular Function, Right / Q000502:physiology