Novel Technique for Measurement of Fetal Right Myocardial Performance Index Using Dual Gate Pulsed-Wave Doppler

How Automated Techniques Ease Functional Assessment of the Fetal Heart: Applicability of MPI+™ for Direct Quantification of the Modified Myocardial Performance Index

(1) Objectives: In utero functional cardiac assessments using echocardiography have become increasingly important. The myocardial performance index (MPI, Tei index) is currently used to evaluate fetal cardiac anatomy, hemodynamics and function. An ultrasound examination is highly examiner-dependent, and training is of enormous significance in terms of proper application and subsequent interpretation. Future experts will progressively be guided by applications of artificial intelligence, on whose algorithms prenatal diagnostics will rely on increasingly. The objective of this study was to demonstrate the feasibility of whether less experienced operators might benefit from an automated tool of MPI quantification in the clinical routine. (2) Methods: In this study, a total of 85 unselected, normal, singleton, second- and third-trimester fetuses with normofrequent heart rates were examined by a targeted ultrasound. The modified right ventricular MPI (RV-Mod-MPI) was measured, both by a beginner and an expert. A calculation was performed semiautomatically using a Samsung Hera W10 ultrasound system (MPI+™, Samsung Healthcare, Gangwon-do, South Korea) by taking separate recordings of the right ventricle's in- and outflow using a conventional pulsed-wave Doppler. The measured RV-Mod-MPI values were assigned to gestational age. The data were compared between the beginner and the expert using a Bland-Altman plot to test the agreement between both operators, and the intraclass correlation was calculated. (3) Results: The mean maternal age was 32 years (19 to 42 years), and the mean maternal pre-pregnancy body mass index was 24.85 kg/m² (ranging from 17.11 to 44.08 kg/m²). The mean gestational age was 24.44 weeks (ranging from 19.29 to 36.43 weeks). The averaged RV-Mod-MPI value of the beginner was 0.513 ± 0.09, and that of the expert was 0.501 ± 0.08. Between the beginner and the expert, the measured RV-Mod-MPI values indicated a similar distribution. The statistical analysis showed a Bland-Altman bias of 0.01136 (95% limits of agreement from -0.1674 to 0.1902). The intraclass correlation coefficient was 0.624 (95% confidence interval from 0.423 to 0.755). (4) Conclusions: For experts as well as for beginners, the RV-Mod-MPI is an excellent diagnostic tool for the assessment of fetal cardiac function. It is a time-saving procedure, offers an intuitive user interface and is easy to learn. There is no additional effort required to measure the RV-Mod-MPI. In times of reduced resources, such assisted systems of fast value acquisition represent clear added value. The establishment of the automated measurement of the RV-Mod-MPI in clinical routine should be the next level in cardiac function assessment.

Double Doppler Tei index combined with lung ultrasound to evaluate the right ventricular function and lung condition in neonates with pulmonary hypertension

PURPOSE

To explore the applicability of the Tei index combined with lung ultrasound score (LUS) in the evaluation of the lung condition and the right ventricular function of patients with neonatal pulmonary hypertension (PH).

METHODS

Thirty healthy neonates and 75 neonates with PH were included. Two-dimensional, M-mode, and double Doppler ultrasound were used to detect RVFAC, TAPSE, TAPSV, and double Doppler Tei index (DD-Tei index). Intra-group correlation coefficient (ICC), Bland-Altman, the Spearman rank method, and the ROC (receiver operating characteristic) were used for other objectives within the study. LUS was used to score the lung condition of 75 neonates with PH with or without respiratory distress and 30 normal neonates in the control group, and the differences were compared. Spearman rank correlation was used to analyze the lung score, DD-Tei index, pulmonary artery pressure, assisted breathing therapy, and the correlation of invasive mechanical ventilation.

RESULTS

There were statistically significant differences in the decrease of the values of RVFAC, TAPSE, TAPSV, and the increase of the DD-Tei index among the groups. RVFAC, TAPSE, TAPSV, and DD-Tei index showed good performance for PH, and the DD-Tei index had the best diagnostic performance. The increase in pulmonary artery pressure, lung score, and DD-Tei index in the PH were statistically significant compared with the control group. The DD-Tei index and lung scores were positively correlated with pulmonary artery pressure, assisted breathing therapy, and invasive mechanical ventilation.

CONCLUSION

Dual Doppler ultrasonography combined with pulmonary ultrasound performed well in the assessment of the right ventricular function and lung condition of neonatal with PH.

Comparison between conventional duplex ultrasonography and the dual-gate Doppler mode for hemodynamic measurements of the carotid arteries

Purpose

This study investigated the correlations of hemodynamic parameters measured to quantify stenosis between the gold-standard duplex ultrasonography and the dual-gate Doppler mode.

Methods

Patients examined due to suspicion of carotid artery stenosis or for surveillance of known stenosis were invited to participate in this prospective single-center study. Upon acceptance, the hemodynamic characteristics of the carotid arteries were determined successively in standard duplex and dual-gate Doppler modes. The correlations between the two modes were analyzed by computing Pearson coefficients (r²) and Lin concordance coefficients (ρ_c). The degree of agreement between the two methods was visualized using Bland-Altman graphical representations.

Results

The correlation between internal carotid artery peak systolic velocity measured by standard duplex ultrasonography and dual-gate Doppler mode was good (r²=0.642). The same high level of correlation was observed for the carotid ratio (r²=0.544). However, the Bland-Altman graphical representation and the Lin concordance coefficients (ρ_c=0.75 and ρ_c=0.74 for the internal carotid artery peak systolic velocity and carotid ratio, respectively) showed that a lack of precision generated some discrepancies between the two measurement methods.

Conclusion

Although some discrepancies were observed, the hemodynamic measurements were closely correlated between the two ultrasonography modes. Therefore, the dual-gate Doppler mode may have obvious advantages over conventional ultrasonography, offering interesting development possibilities.

Assessment of fetal cardiac function with echocardiography

The circulatory physiology of fetuses differs from that of neonates. The concept of biventricular combined cardiac output is necessary to understand and assess the fetal cardiac function. Fetal cardiac function has been estimated using echocardiographic methods such as M-mode, B-mode and pulsed wave Doppler. In addition, recent studies have reported the utility of tissue Doppler imaging in fetal echocardiography. However, parameters for fetal cardiac function remain to be established. Recently, we developed two novel techniques for assessing fetal cardiac function: an automatic fractional shortening method and E/e' determination using the dual-gate Doppler method. These two techniques are expected to be reliable and useful for assessing the fetal status in various pathological conditions.

Assessment of diastolic function of normal fetal heart using dual-gate Doppler

OBJECTIVES

The ratio of mitral peak early diastolic filling to early diastolic mitral annular velocity (E/e') reflects diastolic cardiac function in adults. Dual-gate Doppler (DD) enables measurements of E/e' in the same heart beat. This study was designed to assess the utility of the DD method for measurement of fetal E/e' and determine reference ranges for normal fetuses.

METHODS

This prospective study comprised normal singleton pregnancies undergoing fetal echocardiography between 16 and 36 weeks of gestation. According to the DD method, E-wave velocity on pulsed-wave Doppler and e'-wave on tissue Doppler imaging were measured simultaneously on an apical or basal four-chamber view, and fetal E/e' was calculated. Spearman's correlation coefficient was used to assess the relationship between gestational age (GA) and E-wave and e'-wave velocities and E/e'.

RESULTS

A total of 133 pregnancies were included in this study and all E/e' measurements were successful. Significant correlation was observed between GA and both left ventricular (LV) E/e' (r _s  = -0.666, P < 0.001) and right ventricular (RV) E/e' (r _s  = -0.607, P < 0.001). The regression equations for bilateral E/e' were: LV-E/e' = 17.341 - 0.631GA + 0.008 × GA² (mean ± SD, R ²  = 0.440 ± 1.333); and RV-E/e' = 19.156 - 0.794GA + 0.012GA² (R ²  = 0.419 ± 1.329).

CONCLUSIONS

Bilateral E/e' of normal fetuses, measured using the DD method, decreased with GA, which is considered to be related to myocardial maturity. DD is a useful and convenient method for evaluating fetal E/e' in order to assess diastolic function in the prenatal period. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.