ViosWorks: A Paradigm Shift in Cardiac MR Imaging

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1 Figure 1. ViosWorks image of a patient with shunted pulmonary venous return. Image courtesy of Dr. Shreyas Vasanawala, Stanford University. ViosWorks: A Paradigm Shift in Cardiac MR Imaging The value of Cardiac MR (CMR) is well-documented in the literature. However, CMR has historically been a complex and time-consuming exam to perform, lasting over one hour while subjecting the patient to multiple breath holds and requiring precision in the acquisition of imaging data with little room for error when capturing constantly moving anatomy. Despite the value of CMR, these limitations continue to complicate image acquisition. Acquiring 2D CMR data to quantify cardiac function and flow has been Not commercially available in all regions. a labor-intensive process requiring technologist expertise and physician supervision until now. New technology could shift this paradigm. ViosWorks is a 4D Flow CMR exam that can be completed in as little as 8 to 10 minutes without breath holds. Powered by Arterys, ViosWorks provides quantitative cardiac measurements including flow, regurgitant fraction, stroke volume, ventricular volumes, and ejection fractions precisely and non-invasively. ViosWorks acquires anatomic and velocity information for every location in an entire imaged volume set and at every time point in the cardiac cycle. Specific localization is no longer necessary, and the promise is that a cardiovascular imager may not need to be present at the scanner to aid the MR technologist. Fairfax Radiological Associates (Fairfax, VA) and Institut Mutualiste Montsouris (Paris) are both early adopters of the ViosWorks technology and served as clinical evaluation sites for GE Healthcare. GESIGNAPULSE.COM 39 AUTUMN 2016

2 Jean-François Paul, MD, is a radiologist and Chief of Cardiac Imaging, Institut Mutualiste Montsouris, Paris, France. Institut Mutualiste Montsouris (IMM) Jean-François Paul, MD, has been performing CMR exams for over a decade. For the last year, he s used ViosWorks on an Optima MR450w 1.5T scanner on over 200 patients with valvular conditions referred to MR following an inconclusive Doppler ultrasound exam. While Doppler ultrasound is the current gold standard, Dr. Paul says it cannot always provide a precise answer on whether the patient should undergo surgery in cases with a poor acoustic window. ViosWorks, however, is routinely providing the information he needs for patient management decisions. ViosWorks provides me a view of the complete anatomy of the heart, including the flows within the four chambers and large vessels, Dr. Paul explains. I can study flow patterns throughout the cardiac cycle, visualize turbulences such as vortex, and quantify flows such as regurgitations. No other imaging modality, not even classic 2D Flow MR, can provide such a complete picture. At IMM, Dr. Paul and his colleagues have performed a comparison of ViosWorks with Doppler ultrasound on patients with aortic regurgitation. Regarding our experience, we are convinced that when appropriately performed, ViosWorks gives more precise results than Doppler ultrasound, Dr. Paul adds. I am convinced that this technique will play a more important role in the near future for patients with cardiac disease. The potential number of patients who may Figure 2. 4D Flow image from patient with mitral bioprothesis shows accelerated flow in the mitral valve with a significant pressure gradient. In addition, 4D Flow shows severe mitral regurgitation, which was not reported by echocardiography. Image courtesy of Institut Mutualiste Montsouris. Figure 3. Atrial septal defect, with unilateral left to right shunt, is easily depicted using 4D Flow. 4D Flow permits direct shunt quantification as well as indirect shunt quantification via pulmonary flow (Qp) and systemic flow (Qs) measurement differences. Both approaches measured the shunt at 2.3 L/min, thus shunt closure was indicated and successfully performed using an Amplatzer device. Image courtesy of Institut Mutualiste Montsouris. benefit from it is huge, if you consider 20 million Doppler ultrasound exams are performed every year in the US. Beyond valvular disease, Dr. Paul sees great potential to utilize ViosWorks in cases of congenital heart disease, pulmonary hypertension, and aortic root surgery. GEHEALTHCARE.COM/MR 40 AUTUMN 2016

3 Melany Atkins, MD, is a radiologist and the Director of Cardiac Imaging at Fairfax Radiological Consultants. Fairfax Radiological Consultants (FRC) Melany Atkins, MD, Director of Cardiac Imaging, FRC, specializes in cardiac and body MR and cardiac CT. While she first started using ViosWorks on a Discovery MR750w We are very happy with the results and we are relying on the flow data that we acquire, more so than the traditional data, she adds. The most significant benefit is the reduction in time to acquire the 4D Flow/ViosWorks study. Currently, the the data after the fact, she explains. Plus, since the sequence acquires comprehensive flow data, if a clinical question is raised after the exam, she can go back and perform additional measurements. In addition, there is no risk of being in the wrong imaging plane. 3.0T scanner in early 2016, there has 4D Flow portion of the exam is between If we acquire 4D Flow, then I know we been a significant uptick in utilization 7.5 and 8.5 minutes with no breath holds. will have good flow data. I can go back beginning in May The use of ViosWorks has evolved in our practice and we ve started using it on all cardiac MR exams to help improve the quality of the sequence Dr. Atkins believes that as the practice continues to use ViosWorks, they may be able to reduce many of the traditional sequences and significantly reduce scan time. As the contrast resolution to the data set and process additional flow information from any vessel in the field of view. From that point, I m much less nervous when evaluating a complex congenital heart, she adds. at our facility, Dr. Atkins says. It also continues to improve, we can Also impressive is the Arterys enables the technologist to be more potentially reduce many of the cloud-based processing, adds Dr. comfortable acquiring the images. sequences we are currently acquiring. Atkins. What once took hours of Beginning in June, Dr. Atkins and her colleagues began using the ViosWorks imaging data to support their patient management decisions. The 40 patients imaged so far represent a wide range of conditions, including normal patients without valvular disease and adults and pediatrics ViosWorks may be beneficial for the clinician s productivity as well; Dr. Atkins cannot always be present at the scanner for an entire CMR study. Prescription of the image plane is important to obtain a true double oblique image, otherwise it is possible for the flow data to be incorrect. computer processing time now can be accomplished in minutes. The technologists at FRC love the solution as well they simply acquire the data and then upload it. That part is just amazing. And, with everything cloudbased, it is so easy to access from any location, she adds. with congenital heart disease. The beauty of ViosWorks is that it acquires flow data for the entire data set. I can then go back and process ViosWorks is a technology that may be able to change our practice, Dr. Atkins says. It adds great value in both our pediatric and adult cardiac cases. Jean-François Paul, MD, is a radiologist and Chief of Cardiac Imaging, Institut Mutualiste Montsouris, Paris, France. Melany Atkins, MD, is a radiologist and the Director of Cardiac Imaging at Fairfax Radiological Consultants. Dr. Atkins specializes in cardiac and body MR and cardiac CT. GESIGNAPULSE.COM 41 AUTUMN 2016

4 Evaluating Pulmonic Stenosis and Aortic Regurgitation with ViosWorks/4D Flow Case courtesy of Dr. Melany Atkins, Fairfax Radiological Consultants, Fairfax, VA. Patient history 68-year-old patient presented with progressive shortness of breath and fatigue. He had noticed decreased exercise tolerance. The patient had a history of congenital aortic stenosis status post-ross procedure. He has undergone routine follow up for known neoaortic root dilatation. MR technique Multiplanar, multisequence 3.0T imaging was performed utilizing SA FIESTA, HLA FIESTA, SA T2 DIR, and 2D Phase contrast imaging through the main PA and aorta. Dedicated ViosWorks/4D Flow performed after administration of 10 cc of intravenous ABLAVAR prior to traditional MRA imaging. Post processing via Arterys (ViosWorks) cloud-based software. 4D Flow Parameters Flip angle: 15 degrees TR: 4.70 TE: 2.14 Venc: 300 cm/sec Scan time: 8 min, 50 sec Figure 4. 3D image from the 4D Flow dataset demonstrating the ascending aorta and pulmonary outflow tract/main pulmonary arteries with streamline overlay. The streamline overlay illustrates directional flow. Figure 5. Oblique view along the long axis of the pulmonary outflow tract and main pulmonary artery demonstrating pulmonic stenosis. The adjacent trileaflet aortic valve autograft demonstrates normal leaflet excursion. Figure 6. 3D image from the 4D Flow dataset demonstrating pulmonic stenosis at the level of the pulmonic valve replacement. Figure 7. 3D image from the 4D Flow dataset demonstrating post-surgical change associated with Ross procedure. Mild aortic regurgitation from the aortic valve autograft. Mild aneurysmal dilatation of the ascending thoracic aorta. GEHEALTHCARE.COM/MR 42 AUTUMN 2016

5 Figure 8. Flow dynamics from the Main PA at the level of pulmonic stenosis. Minimal pulmonic regurgitation is associated. Figure 9. Three-plane localization at the level of the main pulmonary artery for flow quantification. MR Findings Dedicated 4D Flow images processed via ViosWorks/Arterys cloud-based software demonstrate post-surgical change associated with prior Ross procedure. Pulmonic stenosis is demonstrated with elevated peak systolic velocity. Flow curves demonstrate mild pulmonic regurgitation. The ascending aorta allograft demonstrates stable dilatation with mild aortic regurgitation. The patient was referred for Melody valve placement. GESIGNAPULSE.COM 43 AUTUMN 2016