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The transition from echo-only to multimodal is not a fashion effect

EuroEcho-Imaging 2017

The “European Association of Echo” several years ago became the “European Association of Cardiovascular Imaging” (EACVI) to recognise the transition from the society being “echo only” to being one that embraces all cardiovascular imaging modalities. Congress News reviews why this shift from single modality to multimodality is not a case of “jumping on the bandwagon”.

Imaging


cosyns_bernard-2016.jpgThe “bandwagon effect” is a phenomenon whereby the rate of uptake of new beliefs, ideas, and trends increases the more they have already been adopted by others—regardless of the underlying evidence. It can also represent the overwhelming acceptance of ideas that are not validated but are popular, which can lead to inappropriate treatment or management of patients.

According to Professor Bernard Cosyns (Universitair Ziekenhuis Brussel, Brussels, Belgium), by promoting a multimodal imaging approach, the EACVI has a heavy responsibility because the association is “convincing a large audience to use new technologies, which would cause problems if the imaging techniques were used inappropriately”. Furthermore, he points out that there is a potential economic burden when considering new techniques—he notes that budgetary concerns may prompt a slowdown in uptake of multimodal imaging. “When we look at multimodal imaging in cardiology, the costs are increasing dramatically, and this may be an issue,” Prof. Cosyns comments.

Therefore, to ensure that the EACVI’s move towards multimodal imaging does not lead to inappropriate use of techniques or undue costs, the society has created a taskforce dedicated to defining multimodal imaging. Led by Doctor Kevin Fox (Imperial College Healthcare Trust, London, UK), the taskforce already proposes the working definition of multimodal imaging “being imaging of the heart based around disease pathology and presentation, integrating complimentary information from different non-invasive imaging modalities performed separately or simultaneously”. Additionally, multimodal imaging should—the taskforce believes—offer the most cost-and clinical-effectiveness testing for the patient.

The taskforce is looking for evidence that a combination of techniques creates synergies, similar to those seen with modern smartphones. The value of apps on smartphones can multiply when used together (for example, mail and calendar apps) compared with their individual value. “If we move to multimodal imaging—and in reality we have to—we need some evidence to show that it can produce better results than the individual modalities by themselves. That is the present challenge,” Prof. Cosyns notes.

Cross validation between modalities, leading to duplication of diagnostic results, should be avoided. It, Prof. Cosyns reports, can “increase costs dramatically”. He adds: “EACVI must rationalise the use of multimodal imaging. Another issue will be the integration of data from different sources.”

Fusion or hybrid imaging is a potential solution to this issue.“An image can be acquired from separate modalities, and spatially registered. But this registration can be difficult. In particular, the treating position of the patient has to change between acquisitions,” explains Prof. Cosyns. He adds: “We can use a hybrid technique of multimodal imaging which decreases the registration problem. Moreover, everything can be done in one acquisition, reducing total scanning time, and allowing you to get all the information at the same time. You can then merge them in the most appropriate way.” Multimodal imaging, on the other hand, encompasses a range of methods in which the techniques are used separately and sequentially for diagnosis. The term multimodal encompasses both of these methods.”

For example, a patient with suspected pericardial constriction will have an echo as first-line examination. The patient may need to undergo further imaging to determine the extent of the disease and/or to assess the best treatment approach. In this particular example, Computed tomography (CT) is required to assess the localisation and the extent of pericardial calcifications, which cannot be seen with echocardiography (echo). Cardiac magnetic resonance (MR) imaging may also be needed to examine the extent of fibrosis in the myocardium (which, if extended, would mean surgery was not an option). In these situations, all imaging modalities approach may be mandatory.

Certification in techniques

The EACVI currently offers separate certification and training for different imaging modalities. But, it plans to introduce a training process with a core syllabus that can merge all of the different modalities.

“If we look back to 10 years ago, a multimodal training programme was already proposed for PET [positron emission tomography] /SPECT [single photon emission computed tomography] CT fusion imaging,  because radiology was much more centred on anatomy, and SPECT and PET were focused on function. We cannot waste this opportunity to train cardiologists today, to certify them and improve their knowledge, and to provide our members with the possibility of training in multimodal imaging too.”

However, by endorsing multimodal imaging, the EACVI is not suggesting it should be used in every patient.

Prof. Cosyns explains: “That is also the role of the association—training people to know the advantages and limitations of multimodal imaging. We need to help people understand the sensitivity and specificity of each modality and the related costs. Furthermore, we want clinicians to be able to take into account the expertise available in their own centre, and then create a framework to use the modalities in the most appropriate way; we want them to develop a stepwise approach.”

Therefore, the message from the EACVI is to only use multimodal imaging in circumstances that are relevant and suitable.

Also, Prof. Cosyns cautions clinicians against “jumping on the bandwagon” of using multimodal imaging simply because it is “hot, it is new and gives you a little bit more information”.

He notes:“Clinicians are the gatekeepers for the appropriate use of different modalities, stating which one should be used and which one should be used first. That is why the integration of data from different sources is so important.

At EuroEcho-Imaging, there are individual tracks for the different imaging modalities—for example, echo, cardiac MR, and computed tomography (CT)—but there is also a track on multimodal imaging.