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Page 2 of 15 Rong et al. Vessel Plus 2019;3:18 I http://dx.doi.org/10.20517/2574-1209.2019.007

echocardiographic examination for transthoracic and transesophageal echocardiography allow the physician
to obtain crucial information on cardiac structures, function, and hemodynamics in a remarkably quick and
non-invasive or minimally invasive manner. In recent years, the never-ending quest for better quality and
more detailed images, fueled by the invaluable contribution of the newest advances in hardware and software
[3]
technologies, has led physicians to “usher in the third dimension” . Three-dimensional echocardiography
(3D echo) can potentially overcome many of the limitations intrinsic to mono- and bi-dimensional
echocardiography. The great opportunities offered by this relatively novel technique have aroused the interest
of many: In order to give a sense of it, a total of 9631 papers could be retrieved on Pubmed by searching “three
dimensional echocardiography” (April, 2019).

This review aims to provide an overview on the applications of 3D echo, with particular reference to the
perioperative settings.

THREE-DIMENSIONAL ECHOCARDIOGRAPHIC EVALUATION OF CARDIAC STRUCTURES
As a general principle, 3D echo is based on the acquisition of pyramidal datasets used to sample the cardiac
structures of interest, acquired over a single beat [real-time (RT)] or several beats (multi-beat). Multi-beat
acquisitions use ECG gating to “stitch” volume slices together by means of a dedicated software to generate a
[3]
3D image .

The accuracy and feasibility of 3D echo in studying valvular and congenital lesions has been largely
demonstrated in the operating room, where 3D transesophageal echo (3D TEE) has been able to accurately
predict valve morphology and provide complementary anatomic information to two-dimensional TEE (2D
[4]
TEE) . Unsurprisingly, 3D TEE has now been widely integrated into the workflow for guiding complex
[5]
interventional procedures .
Adequate 2D image quality is an essential prerequisite for the evaluation of any cardiac structure by means
of 3D echo. Moreover, inclusion of the entire cardiac structure of interest within the pyramidal dataset is
of utmost importance. Of note, this can be quite challenging in patients with dilated ventricles (both left or
right ventricle).

Once images are acquired, a key advantage of 3D over 2D echo is represented by the fact that measurements
do not rely on any geometric assumptions. Dataset analysis is therefore not affected by foreshortened or off-
axis views, as opposed to traditional 2D assessment.

However, the higher spatial resolution of 3D echo comes at the expense of lower temporal resolution, as
compared to other echo modalities; while this might constitute a disadvantage (especially when assessing
[6]
regional wall motion), careful technical adjustments of the images might still provide reasonable accuracy .
Of note, poor temporal resolution could be improved by a multi-beat acquisition that stitches volumes
together. Notably, this modality requires a motionless patient (without interference of electrocautery,
arrhythmias, or ventilation).

With the advent of newer, more powerful TEE and TTE probes, this issue has been significantly improved
with adequate frame rates from a single beat acquisition.

[7]
Nevertheless, as elegantly summarized by Surkova and colleagues , the specific advantages of 3D echo over
other imaging modalities - including its portability, absence of ionizing radiation, and the full compatibility
with implanted cardiac devices like pacemakers and defibrillators- outweigh the aforementioned limitations
in most cases.