Assessment of Left Ventricular Regional Wall Motion
by Denisa Muraru, MD, PhD; Veronica Spadotto, MD; Luigi P. Badano, MD, PhD
Department of cardiac, thoracic and vascular sciences, University of Padua, School of Medicine, Padua, Italy
Soccer player, no apparent cardiovascular risk factors
Admitted with anterior STEMI treated by primary PCI, with no subsequent complications
Echocardiographic assessment of left ventricular (LV) regional wall motion pre-discharge
Two-dimensional views of the LV acquired in sequence and displayed in quad-view (4-ch, 2-ch, APLAX and PSAX), showing mild wall motion abnormalities limited at the LV apex (septal and anterior segments)
Multi-beat 3D transthoracic LV dataset displayed in quad-view (4-ch, 2-ch, APLAX and PSAX), after obtaining optimal alignment. To eliminate foreshortening, the vertical axis (dashed grey line) was set to cross the apex in all three planes. The entire 3D dataset was then rotated around its vertical axis, so that the 2-ch plane crossed the inferior wall in short-axis view at the infero-medial papillary muscle level. Note the differences in comparison with 2D views in terms of LV length (no more foreshortening) and wall motion (now evident akinesia involving apical and mid segments of anterior and antero-septal walls).
On short-axis view, by small clockwise rotation, the white line corresponding to the 2-ch view was set to cross the inferior wall close to the junction with inferior septum. Now, the “2-ch view” is very similar to the one above acquired by 2D echocardiography, and anterior wall motion appears only minimally affected (cutplane is farther than antero-septum, close to antero-lateral wall). This simulation shows that with 2D echocardiography, small variations in probe rotation from 4-ch to 2-ch view may lead to significant differences in LV wall motion interpretation in such cases.
Acquisition of a 3D full-volume dataset of the LV enables the observer to display it using various multi-slice options. Thus, three-dimensional echocardiography provides a complete visualization of the LV endocardial border displacement and myocardial thickening, allowing to actually “see” the LV regional wall motion.
The 3D dataset has been sliced in 12 cut planes: 3 longitudinal (apical 4- and 2-chamber and long-axis) on the left, and 9 equidistant transversal cut planes (from the base to the apex) on the right. All these planes can be manually adjusted (by translation and rotation) to correct for apical foreshortening and off-axis views. These maneuvers allow to visualize the entire 3D surface of all LV segments.
Obtaining a correct alignment of apical planes before interpreting the LV wall motion on 3D datasets is critically important. Here is the same 3D dataset displayed in quad-view, before alignment of apical planes (longitudinal grey line does not cross the apex in 4-ch and 2-ch). Note again the differences in LV wall motion in comparison with the dataset correctly aligned from above (upper left image).
Multiple short-axis views by cardiac magnetic resonance showing the extent and the distribution of the late gadolinium enhancement within the LV myocardium.
Four- and 2-chamber and long-axis views by cardiac magnetic resonance showing transmural late gadolinium enhancement pattern involving the LV apex, mid anterior and mid septal regions.
When we use 2D echocardiography to assess regional wall motion in a certain LV segment, we assume that:
The wall motion abnormality (score) seen in that 2D slice of few mm thickness is representative of the actual wall motion of the entire 3D chunk representing the myocardial segment
The acquired longitudinal 2D views of the LV are anatomically correct and displaying the same segments always in the same way
Actually, standard 2D views show around 10% of the actual LV endocardial surface. If the regional abnormality does not encompass the entire LV segment, a 2D tomographic plane crossing that segment may show variable extents of this abnormality or even miss it completely, depending on its relative orientation. Finally, the common anatomic landmarks of standard 2D views allow a quite large latitude from echocardiographers in obtaining the LV cut planes, and not infrequently these are revealed as incorrect only after comparison with the respective slice obtained from a 3D dataset of the same LV, after adequate aligment.
Conventional views cover only a very limited surface of actual left ventricular endocardium
We assume that the wall motion seen in these thin slices of myocardium is representative of the wall motion occuring in the much larger areas located in between the standard 2D views
Assessment of LV wall motion score is heavily dependent on the way LV 2D views are acquired
Suboptimal 2D views can sometimes go unrecognized, since the anatomical landmarks for “correct” LV standard planes are neither precise nor verifiable by 2D only
2D views, once acquired and recorded, cannot be modified anymore in their position or orientation
Enables the actual visualization of the endocardial displacement and thickening of the entire LV myocardium
The orientation and the position of the cut-planes can be easily re-adjusted during post-processing without limitations, allowing to obtain anatomically sound, non-foreshortened views
Wall motion is assigned by visualization of the longitudinal and circumferential extent of wall motion abnormalities instead of making assumptions from few 2D slices
3D datasets can be fused with CT, CMR and nuclear cardiology datasets for anatomical and functional correlations
Lang RM, Badano LP, Mor-Avi V et al. Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr 2015;28(1):1-39.
Badano LP. The clinical benefits of adding a third dimension to assess the left ventricle with echocardiography. Scientifica (Cairo). 2014;2014:897431.