Scientific blogs
In December 2021, Medis introduced its newest solution, the Medis Suite Ultrasound: the vendor-independent software solution for echocardiographic applications. In this blog we would like to inform you on all the exciting developments in Medis Suite Ultrasound and why Medis Suite Ultrasound might look very familiar to you!
Although just released as Medis Suite Ultrasound, the roots of the current software solution go back more than two decades. It all started with the Italian company AMID: they saw the need for advanced cardiac deformation analysis in echocardiography and decided to develop the technology and the associated software solutions on a thorough scientific basis, using solid and robust feature tracking technology.
The AMID software, originally named DIOGENES, has been integrated over the years in many different cardiovascular ultrasound OEM solutions, such as, Tomtec Image Arena – 2D CPA, Siemens VVI, VisualSonics Vevo Strain and Vevo Vasc, GE Women’s Health Voluson console – part of the FetalHQ software, and many more.
AMID was acquired by Medis in 2020, and the software was further developed not only to be vendor independent, but also to become modality independent. The AMID solution is now integrated into the powerful Medis Suite engine, that also powers the Medis’ MR and CT solutions.
Echo Speckle Tracking
CT Feature Tracking
MR Feature Tracking
Beyond ejection fraction: an integrative approach for assessment of cardiac structure and function in heart failure, Maja Cikes and Scott D. Solomon, European Heart Journal, 2016 [1]
Together with the launch of the new Medis Suite Ultrasound, Medis organized a webinar to introduce the solution to the cardiovascular imaging community. In case you have missed the webinar, or wish to revisit, the Webinar, here is the link: https://youtu.be/gPHbeV0RoIs
Medis has always been on the forefront of advancing cardiac deformation analysis in daily clinical practice. With the introduction of the robust speckle-tracking technology, Global Longitudinal Strain (GLS), Global Circumferential Strain (GCS) and Global Radial Strain (GRS), as well as their regional values, became available, which have led to impressive numbers of publications on strain. Over the years, the AMID-based strain solution has been included in the international literature in more than 1400 scientific publications.
Moreover, the same Strain analyses could also apply to the right ventricle (RV) and left atrium (LA).
Global longitudinal strain (GLS) in the left ventricle is becoming a more integral part of studying cardiac function. Scientific research shows that Left Ventricular Global Longitudinal Strain (LV GLS) is a more sensitive marker to evaluate changes in LV function, than Ejection Fraction (EF). For instance, it is well known that EF has its limitations when it comes to identifying early onset heart failure. Whereas, GLS has demonstrated that it can detect the dysfunction at an earlier stage. Figure 2 from the paper of Maja Cikes and Scott D. Solomon depicts nicely that the longitudinal circumferential deformation already declines, while the LVEF remains stable [1]. The GLS can be derived from Echo images that are already acquired during routine clinical imaging sessions; in Echo series they are commonly referred to as 2-, 3- and 4-chamber apical views.
With the acceptance of Global Longitudinal Strain, describing the global LV function, the question for a robust and sensitive regional LV function parameter arises. Regional strain gives information on the regional ventricular dysfunction, by measuring the difference of parallel displacement between the two edges of a segment. Unfortunately, the sensitivity of regional strain has been shown to be relatively low. This is due to the fact, that small changes in the length of a segment along the perimeter of the left heart chamber can be difficult to detect.
Over the past 40+ years, various left ventricular wall motion models have been developed for X-ray angiography, and is also applied to the other imaging modalities, such as echocardiography, MRI and CT. The most well-known model is the centerline model, which is based on the changes in position of individual points along the LV perimeter from ED to ES and perpendicular to the centerline between the ED and ES contours. However, it is not based on a solid wall motion model.
The feature tracking technology has provided much more information about the actual displacement of the individual positions along the left ventricular boundary. Based on that solid technology, we have been able to create an actual left ventricular wall motion model that made clear that points along the contour are moving to well-defined “centers of contraction”. This “Inward Displacement” model now allows for an objective assessment of regional function. The basic principles of the model are visualized in Fig. 3.
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Basic principles of the new regional wall motion model depicted. Points along the perimeter of the left ventricle have their own point of contraction. This allows to assess the regional wall motion on a solid model based on feature technology.
The combination of radial and longitudinal motion is captured that causes the reduction of the LV volume. In the video of Fig.4, the inward displacement is displaced, in red the normal inward motion and in blue an area with dyskinesia. Since the parameter was developed on the Medis Suite platform, it can be used on the other Medis Suite modalities, Echo and MRT, as well, making it easy to compare.
Fig. 4: In this video the regional wall motion is visualized: in red normal inward displacement, in blue an area with regional dyskinesia.
Recently, De la Pena-Almaguer et al. described in a case the potential of the regional ventricular dysfunction measured by inward displacement in an infarcted heart [7]. As a novel parameter, Inward Displacement is currently being investigated in multiple interesting studies, that will demonstrate its strength in the assessment of an objective regional parameter for cardiac function.
A next step in the innovation and based on the feature tracking technology is the assessment of the Intraventricular Pressure Gradients (IVGPs) also denoted Hemodynamic Force (HDF) [2]; an example of the HDF analysis is presented in Figure 5. HDF can enable clinicians to detect mechanical abnormalities earlier compared with conventional ejection fraction and strain analysis, and possibly to predict the development of cardiac remodeling.
Left: Typical Hemodynamic forces curves for apex to base direction (red) and inferior Lateral to anterior Septum direction Blue). Right: B-mode Echo series from which Hemodynamic forces curves can be derived. Images adapted from Faganello et al. [3]
Faganello et al. [3] Description of different intervals of the apex-to-base hemodynamic forces curve
A next step in the innovation and based on the feature tracking technology is the assessment of the Intraventricular Pressure Gradients (IVGPs) also denoted Hemodynamic Force (HDF) [2]; an example of the HDF analysis is presented in Figure 5. HDF can enable clinicians to detect mechanical abnormalities earlier compared with conventional ejection fraction and strain analysis, and possibly to predict the development of cardiac remodeling.
Secondly, Vallelonga et al. wrote an interesting paper aiming to introduce the concept of HDF to clinicians [4]. Thereby showing the relation between the different functional analysis parameters (Figure 7) and the evidence supporting HDF in clinical settings.
Temporal evaluation of cardiac mechanics analysis Vallelonga et al [4]
Finding altered diastolic function in patients with precapillary pulmonary hypertension using novel quantitative indices. Vos et al. [5]
In 2021, J Vos et al. assessed Left Ventricular intraventricular pressure gradients as well as Left Atrial Strain in patients with precapillary pulmonary hypertension using CMR (Figure 8). [5]
And in 2022, Dr. Filomena published in ESC Heart Failure, their findings of the impact of intraventricular hemodynamic forces misalignment on the left ventricular remodeling after myocardial infarction, an example case from this paper is shown in figure 9. [6]
Alignment of hemodynamic forces showing different patterns in patients with non-adverse vs adverse remodeling, following myocardial infarcts. Filomena et al. [6]
This all together shows the potential of HDF. At Medis we are tremendously proud that by providing the ability to derive IVPGs from “bread and butter” clinical images we are helping the clinical researchers to break through the new frontier of cardiac physiology!
[1] Cikes, Maja, and Scott D. Solomon. “Beyond ejection fraction: an integrative approach for assessment of cardiac structure and function in heart failure.” Eur Heart J 2016; 37(21): 1642-1650
[2] Pedrizzetti, G. “On the computation of hemodynamic forces in the heart chambers.” J.Biomechanics 2019; 95: 109323.
[3] Faganello, G, et al. “A new integrated approach to cardiac mechanics: reference values for normal left ventricle.” Int J Cardiovasc Imag 2020; 36(11);): 2173-2185.
[4] Vallelonga, F., et al. “Introduction to Hemodynamic Forces Analysis: Moving Into the New Frontier of Cardiac Deformation Analysis.” J Am Heart Assoc 2021; 10(24):: e023417.
[5] Vos, JL., et al. “Cardiovascular magnetic resonance-derived left ventricular intraventricular pressure gradients among patients with precapillary pulmonary hypertension.” Eur Heart J-Cardiovascular Imaging (2022).
[6] Filomena, D., et al. “Impact of intraventricular haemodynamic forces misalignment on left ventricular remodelling after myocardial infarction.” ESC Heart Failure (2021).
[7] de la Pena-Almaguer, E., Hautemann D, Pedrizzetti, G.. “Computed tomography derived left ventricular inward displacement as a novel tool for quantification of segmental wall motion abnormalities.” Int J Cardiovasc Imag. 2021; 37(12): 3589-3590.
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