Dear Medis enthusiasts,
The year 2022 has a very positive outlook for the CT analysis, with an uptake of CT analysis in clinical guidelines and novel CT technologies, such as photon counting, making its way into the clinics. In this blog Medis would like to give an update on all our CT developments, like CT Plaque and CT Strain, and how we think these developments can help you in your daily clinical practice.
CT plaque is being recognized more and more as an important marker to assess in atherosclerotic cardiovascular disease. Medis has developed the QAngio CT solution that helps you quantify plaque in your research by extracting relevant information from CT Angio (CTA) analysis studies. With automated algorithms for tree extraction, contouring, tissue characterization as well as a powerful batch processing of results, the QAngio CT enables you to do your research more efficiently. Interested to see how our QAngio CT solution can help you quantify plaque?
You can find a demonstration of our software solution here: https://youtu.be/TM3ApFiAKrQ
CT Plaque webinar
Medis doesn’t just develop software, we want to push the field of CTA with our solutions. Therefore, we organize webinars throughout the year. Like at the SCCT of 2020, here we gave 3 top researchers, Marton Kolossváry, Parastou Eslami and Matthew Budoff, a platform to talk about their important scientific work in studying CT plaque. To watch the recording of Medis at the SCCT, here’s the link: https://youtu.be/9O5m41rCNCQ
Pericoronary inflammation (in 3D!) – a hot research topic
Over the last few years there has been an increasing interest in pericoronary inflammation. With the use of CT analysis, it is possible to extract intensity information on the coronary vessels. This approach is supported by research, different articles show that this information is linked to coronary inflammation. Already in 2010, a study by Mahabadi et al. reported that there is an association between pericoronary fat and atherosclerosis in the coronary arteries  but also more recently in the study of Oikonomou it is shown that the perivascular fat attenuation index (FAI) enhances the cardiac risk prediction, see Figure 1 . The QAngio CT Research Edition combines the information on the vessels together with stenosis and plaque results, providing you with a more complete picture of the coronary vessels.
The Medis QAngio CT solution even allows you to visualize and export the information in a 3D fashion. Figure 2 shows the PVAT display in the Medis QAngio CT solution, if you want more information on the 3D visualization export options of the QAngio CT solution please click the following link: https://youtu.be/d1niIBkCD3U
CT Strain – A valuable addition for valvular heart disease patients
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).
GLS studies began using echo data roughly 10 years ago, resulting in a CPT code for reimbursement in the United States in 2020 . But GLS wasn’t only studied in echo, GLS measurements have been conducted using MR data for over 5 years and more recently GLS has been measured using CT data.
Especially, because measuring GLS with MR and CT proves to have major upsides over echo. Echo has been known as the workhorse to clinically evaluate cardiac function, but it does have its own challenges when it comes to image quality, operator dependency and reproducibility. MR and CT on the other hand allow for excellent image quality and reproducibility due the high standardization of the acquisition.
However, contrary to regular CT imaging, where you just image a single phase, for CT strain you need the complete cardiac cycle. This doesn’t necessarily lead to more exposure for the patient, since the prolonged imaging is supported for CT imaging regarding aortic valve implantation and replacement (TAVI/TAVR) by an expert consensus document published during SCCT 2019 . This document recommends imaging the complete cardiac cycle, because the information from both the systole as well as the diastole phase is beneficial for valve planning purposes. This means that the prognostic information on LV GLS can be obtained from the same scan of patients undergoing TAVI/TAVR [4,5,9].
And the upside of CT GLS for patients suffering from valvular heart disease has been assessed by recent articles from the Minneapolis Heart Institute and the Leiden University Medical Center. Fukui et al. have found that assessing the CTA-LV GLS in a low-risk TAVR cohort of patients was highly feasible, improving risk stratification by providing independent and incremental prognostic value over clinical and echocardiographic characteristics . Figure 3 shows how TAVR affects the GLS value after 1 month. Hirasawa et al. showed that the marker of LA reservoir function, peak left atrial longitudinal strain can be measured using feature tracking multidetector CT which showed a good agreement with echo in a cohort of patients with aortic stenosis .
The latest advancements show the upside of using CT over echo while assessing GLS, due to their excellent image quality and high reproducibility. This claim further strengthened by the SCCT document for CT imaging in TAVI/TAVR . The recommendation to image the entire cardiac cycle makes it possible to get additional prognostic information for CT strain that proves to be beneficial for patients suffering from valvular heart disease.
Inward Displacement – The next step in the independent parameter for regional LV function
With the acceptation of GLS, describing the global LV function, in the study of cardiac function, the question for a feasible 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.
Based on experiences in the field, Medis has developed Inward Displacement to better and objectively characterize regional dysfunction. This measures the inward motion of the endocardial wall towards the ‘center of contraction’. The combination of radial and longitudinal motion is captured that causes the reduction of the LV volume. In the image you can see the inward displacement 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 MR, as well, making it easy to compare.
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. Besides information on global LV function using GLS, the novel parameter can be used as an objective measurement to get information on regional ventricular dysfunction. Inward Displacement is currently being investigated in multiple interesting studies, proving to be a useful parameter for cardiac function in the future.
More about Medis Suite CT
With all this developments Medis is very excited about the future of CT analysis. If you are as excited as we are, it is possible for you to try Medis Suite CT yourself and experience the benefits it can bring to your daily clinical practice. You can request a trial license here: Product Trial Request – Medis Medical Imaging (medisimaging.com) or get in touch with us by email: firstname.lastname@example.org
 Oikonomou, Evangelos K., et al. “Non-invasive detection of coronary inflammation using computed tomography and prediction of residual cardiovascular risk (the CRISP CT study): a post-hoc analysis of prospective outcome data.” The Lancet 392.10151 (2018): 929-939.
 Mahabadi, Amir A., et al. “Association of pericoronary fat volume with atherosclerotic plaque burden in the underlying coronary artery: a segment analysis.” Atherosclerosis 211.1 (2010): 195-199.
 Gegenava, Tea, et al. “Feature tracking computed tomography-derived left ventricular global longitudinal strain in patients with aortic stenosis: a comparative analysis with echocardiographic measurements.” Journal of cardiovascular computed tomography 14.3 (2020): 240-245.
 Gegenava, Tea, et al. “Prognostic Influence of Feature Tracking Multidetector Row Computed Tomography-Derived Left Ventricular Global Longitudinal Strain in Patients with Aortic Stenosis Treated With Transcatheter Aortic Valve Implantation.” The American journal of cardiology 125.6 (2020): 948-955.
 Fukui, Miho, et al. “Association of baseline and change in global longitudinal strain by computed tomography with post-transcatheter aortic valve replacement outcomes”, European Heart Journal – Cardiovascular Imaging, 2021;, jeab229
 Hirasawa, Kensuke, et al. “Comparison of left atrial strain measured by feature tracking computed tomography and speckle tracking echocardiography in patients with aortic stenosis.” European Heart Journal-Cardiovascular Imaging (2022).
 Cademartiri, Filippo, et al. “Cardiac computed tomography as a complete functional tool.” European Heart Journal-Cardiovascular Imaging (2022).https://academic.oup.com/ehjcimaging/advance-article-abstract/doi/10.1093/ehjci/jeab288/6497617
 de la Pena-Almaguer, Erasmo, David Hautemann, and Gianni Pedrizzetti. “Computed tomography derived left ventricular inward displacement as a novel tool for quantification of segmental wall motion abnormalities.” The International Journal of Cardiovascular Imaging 37.12 (2021): 3589-3590.