Three-dimensional echocardiography for left ventricular quantification: fundamental validation and clinical applications

Abstract

One of the earliest applications of clinical echocardiography is evaluation of left ventricular (LV) function and size. Accurate, reproducible and quantitative evaluation of LV function and size is vital for diagnosis, treatment and prediction of prognosis of heart disease. Early three-dimensional (3D) echocardiographic techniques showed better reproducibility than two-dimensional (2D) echocardiography and narrower limits of agreement for assessment of LV function and size in comparison to reference methods, mostly cardiac magnetic resonance (CMR) imaging, but acquisition methods were cumbersome and a lack of user-friendly analysis software initially precluded widespread use. Through the advent of matrix transducers enabling real-time three-dimensional echocardiography (3DE) and improvements in analysis software featuring semi-automated volumetric analysis, 3D echocardiography evolved into a simple and fast imaging modality for everyday clinical use. 3DE provides the possibility to evaluate the entire LV in three spatial dimensions during the complete cardiac cycle, offering a more accurate and complete quantitative evaluation the LV. Improved efficiency in acquisition and analysis may provide clinicians with important diagnostic information within minutes. The current article reviews the methodology and application of 3DE for quantitative evaluation of the LV, provides the scientific evidence for its current clinical use, and discusses its current limitations and potential future directions.

Fig. 1

Example of the work flow of one of the commercially available software packages. Top, left and right: two perpendicular long-axis images of the LV. The endocardial contour is detected semi-automatically and is projected on the image. Centre left: a third perpendicular short-axis image, again with the endocardial contour. Note that this short-axis image was made with the ultrasound transducer in the apical position. Centre right: The LV ‘cast’ is shown with colour-coding of individual LV segments. Bottom: For each LV segment, a time-volume curve is generated. Regional wall motion and dyssynchrony can be appreciated easily

Fig. 2

Parametric images derived from three-dimensional datasets. Images of a patient are shown with CRT turned off (left) and on (right), respectively. The LV is divided into 16 segments as described by the American Society of Echocardiography. Colour coding is used to represent regional time-to-minimum systolic volume, with red indicating late activation. In the left hand map, the lateral wall is identified as the latest activated LV region without CRT (left). As can be appreciated in the right hand map by the overall homogenous blue colour indicating the absence of large regions with delayed contraction, synchronicity is re-established when CRT is applied (right)

Fig. 3

LV volumes and EF measurements by 3DE: comparison with CMR. In total, we identified 21 studies including 1040 patients (747 males, 60 ± 9 years) in which LV volumes and ejection fraction as measured by 3DE were compared with CMR as the reference method [–, –, –, –29]. Bland-Altman statistics are shown for EDV, ESV, and EF by 3DE in comparison with CMR as the reference method. Mean difference ±2 standard deviations are shown as a percentage of the mean value, as measured by 3DE. Studies are shown in chronological order, with the most recent publications to the right. Jenkins et al. [12]: a TomTec offline, b QLAB online; Soliman et al. [21]: a multiplane interpolation, b full-volume reconstruction; Soliman et al. [22]: a TomTec 4D LV-Analysis ver. 2.0, b QLAB V4.2; Mor-Avi et al. [25]: a CMR short-axis vs. 3DE long-axis image analysis, b CMR and 3DE long-axis image analysis, c trabeculae included in LV volume in CMR analysis, d trabeculae excluded from LV volume in CMR analysis; Chukwu et al. [29]: a normal volunteers, b myocardial infarction patients

Fig. 4

LV volumes and function measurements by 3DE : a intra-observer variability; b inter- observer variability. Legend: To study the reproducibility of LV volumes and EF measurements, we identified 16 studies including 407 patients in which reproducibility of these measurements by 3DE was assessed [, , –, , –25, 28, 30]. Studies are shown in chronological order, with the most recent publications to the right. Kühl et al. [4]: a TomTec CardioView RT semi-automated analysis, b TomTec CardioView RT manual analysis; Soliman et al. [22]: a TomTec 4D LV-Analysis ver. 2.0, b Philips QLAB V4.2; Hansegård et al. [30]: a TomTec 4D LV-Analysis ver. 2.2, b GE 4DLVQ software, EchoPAC ver. 108.1.0