Impact of apical foreshortening on deformation measurements: a report from the EACVI-ASE Strain Standardization Task Force.

AIMS: Foreshortening of apical views is a common problem in echocardiography. It results in an abnormally thick false apex and a shortened left ventricular (LV) long axis. We sought to evaluate the impact of foreshortened (FS) on LV ejection fraction (LVEF) and layer-specific 2D speckle tracking based segmental (S) and global (G) longitudinal strain (LS) measurements. METHODS AND RESULTS: We examined 72 participants using a GE Vivid E9 system. FS apical views were collected from an imaging window one rib-space higher than the optimal images. Ejection fraction as well as layer-specific GLS and SLS measurements were analysed by GE EchoPAC v201 and TomTec Image Arena 4.6 and compared between optimal and FS images. On average, LV long axis was 10% shorter in FS images than in optimal images. FS induced a relative change in LVEF of 3.3% and 6.9% for GE and TomTec, respectively (both, P < 0.001). Endocardial GLS was 9.0% higher with GE and 23.2% with TomTec (P < 0.001). Midwall GLS measurements were less affected (7.8% for GE and 14.1% for TomTec, respectively, both P < 0.001). Segmental strain analysis revealed that the mid-ventricular and apical segments were more affected by foreshortening, and endocardial measurements were more affected than midwall. CONCLUSION: Optimal image geometry is crucial for accurate LV function assessment. Foreshorhening of apical views has a substantial impact on longitudinal strain measurements, predominantly in the apex and in the endocardial layer. Our data suggest that measuring midwall strain might therefore be the more robust approach for clinical routine use.

How Does Regional Hypertrophy Affect Strain Measurements With Different Speckle-Tracking Methods?

BACKGROUND: In this study, we evaluate the impact of abnormal myocardial shapes, such as regional hypertrophy, on longitudinal strain measurements with different tracking approaches. METHODS: We selected 40 patients with normal ejection fraction and prominent septal bulge. We assessed longitudinal strain with full wall (FW) tracking, (GE EchoPAC) as well as endo-, mid-, and epicardial (EME) tracking (Tomtec ImageArena), on the same image acquired with a GE machine (using raw data and full frame rate DICOM data, respectively). We used a region of interest (ROI) which follows precisely the endo- and epicardial contours (true contour ROI) and one where the bulging region was excluded (straight ROI). RESULTS: In segments with bulge, absolute segmental longitudinal strain values were in all myocardial layers significantly higher with a straight ROI compared to a true contour ROI, both with FW tracking and EME tracking. The highest difference was found in the endocardial layer (3.4 ± 2.5% and 7.7 ± 7.1%, respectively, both P < 0.001). In the bulged segments, the effect of ROI shape was more pronounced in EME tracking software compared to FW tracking software. Bulged segments also influenced global longitudinal strain measurements, mostly in the endocardial layer (P < 0.001). Global longitudinal strain values obtained with the straight ROI correlated better with longitudinal fractional shortening of the LV. CONCLUSIONS: Regional bulging has a significant effect on both global and segmental strain measurements. Endocardial strain values obtained with EME tracking and a true contour ROI were most sensitive to bulging. Midwall strain values derived from FW tracking using a straight ROI were most robust.