Fairly well attended session on "Updates in Vascular Images" moderated by Karen Ordovas and Jens Bremerich, who were both moderators and presenters.Stephen J. Riederer (Mayo Clinic) was in charge of the first talk. He gave a short overview on the development of angiology techniques and improvements. Multiple coil techniques as well as parallel imaging techniques and partial Fourier made it possible to improve resolution of images and shorten scan times. He also gave an overview about ongoing developments including Dixon CE MRA which allows to improve image quality further by background fat suppression.After the opening session, James Carr (Northwestern University) gave us interesting insights of "wall structures and shear stress of ascending aorta".
He stated how much the ECG gated CMRA is essential to avoid blurred images and calculate properly aortic measurement . Non- contrast technique can be equally used, making CEMRA and NCMRA are first line test to provide vascular morphology.Clinical applications are various, with bicuspid aortic valve capturing more attention. Any type of Bicuspid Valve causes different pattern of aortic dilatation, but all types shares high elastin disorganisation and flow abnormalities . Sophisticated flow images technique such as 4D flow MRI help substantially to analyse abnormal flow and progression of aneurism formations, providing haemodinamic measurements, including wall shear stress, energy loss and pressure analysis.These imaging technique demonstrate a relationship between haemodinamic abnormalities and hystological findings, useful for guiding surgery. Karen Ordovas (University of California) followed with an interesting lecture on hemodynamic assessment of coarctation. Gradients >20mmHg are a commonly agreed criteria for severe aortic coarctation. However, also lower pressures with evidence of significant collateral flow can be signs of significant coarctation . She stressed the fact that one important criteria for relevant collaterals is flow that it is directed towards the descending aorta. Pressure gradients can be reliably measured by CMR. However, it has to be kept in mind that significant collateral flow can decrease measured pressure gradients. Flow measurements and flow curve profile can give further information about severity of coarctation. Therefore, a combined approach including cross sectional area of the stenotic region as well as flow measurements and assessment of collaterals is recommended.Jens Bremerich (University Hospital) convinced us how MRI is a powerful tool to study 1) angiography 2) pulmonary hypertension 3) perfusionCT is first line test for pulmonary embolism, however MRI stepwise protocol is fairly rapid and very helpful to clarify a lesion seen in CT.In pulmonary hypertension, CT gives us informations on chronic thromboembolic pulmonary hypertension, however MRI gives us additional informations on RV such us mass ratio between LV and RV, LGE in RV, RV strain, eccentricity index.Finally, in perfusion analysis, MR can assess pulmonary physiology in particularly with the Fourier Decomposition technique. Jao Lima (John Hopkins University) presented some results from the MESA (multi ethnic study of atherosclerosis) which was able to show that arterial stiffness increases above the age of 35. Arterial stiffness as a main determinant of age related systolic and pulse pressure increase and a main predictor of stroke myocardial infarction and heart failure. Interestingly, these changes occur at the same time of decline in cardiorespiratory fitness over age.
Chung Young (University of Washington) closed the session explaining us the valid use of MRI in carotid plaque images. He commenced with a provocative question :" is stenosis enough to predict stroke? " . This is what we currently use, but what about "composition of plaque"? . Any Different composition implies different remodelling (stenosis or enlargement ) and has different risk of rupture. MRI helps to identify vulnerable plaque giving additional informations on plaque, including cryogenic plaques . Young gave, in conclusion, an overview on developing technique : -3D MERGE, which is a 3D black blood resolution images ; SNAP which is a pulse sequence design to obtain angiographic images and intra-plaque haemorrhage images and finally MATCH technique.All new techniques are useful to assess plaque composition and risk of plaque rupture with the aim to guide treatment options.
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