4D FLOW: Feasibility Study of a Sequence 4D of Flow Applied to the Cervico-encephalic Vascular Pathologies

Overview

The dynamic angio-MR sequences with injection of contrast (CE ARM) allow the study of the vascular anatomy. These sequences, widely used in clinical routine have shown their utility, in particular in the detection of the cerebrovascular diseases. The 4D flow MR sequences allow to quantify arterial parameters such as the speed of the circulating flow. By allowing an anatomical analysis and a functional analysis of quantitative parameters, 4D flow MR sequences could replace 1/ the currently used dynamic MRA sequences that are less precise in term of spatial and temporal resolution; 2/ the invasive exploration by DSA for the detection of vascular lesion and complete the exploration of the cervico-encephalic vascular pathologies by providing hemodynamical measures not yet accessible in clinical settings. In this context, the aim of the study is to evaluate the feasibility and the clinical usefulness of this 4D Flow technique to image brain vascular disorders including steno occlusive disorders. The evaluation will include several steps: 1/ optimization of acquisition parameters for the cranio-cervical arteries; 2/ comparison of two strategies for the post-processing 3/ feasibility for imaging of brain vascular disorders.

The dynamic angio-MR sequences with injection of contrast (CE ARM) allow the study of the vascular anatomy. These sequences, widely used in clinical routine have shown their utility, in particular in the detection of the cerebrovascular diseases. The 4D flow MR sequences allow to quantify arterial parameters such as the speed of the circulating flow. By allowing an anatomical analysis and a functional analysis of quantitative parameters, 4D flow MR sequences could replace 1/ the currently used dynamic MRA sequences that are less precise in term of spatial and temporal resolution; 2/ the invasive exploration by DSA for the detection of vascular lesion and complete the exploration of the cervico-encephalic vascular pathologies (arterio-venous deformations, cervical or intra-cranial stenoses, intra-cranial aneurysms) by providing hemodynamical measures not yet accessible in clinical settings. In this context, the aim of the study is to evaluate the feasibility and the clinical usefulness of this 4D Flow technique to image brain vascular disorders including steno occlusive disorders. The evaluation will include several steps: 1/ optimization of acquisition parameters for the cranio-cervical arteries; 2/ comparison of two strategies for the post-processing 3/ feasibility for imaging of brain vascular disorders. STUDY HYPOTHESIS \& AIMS The investilgators hypothesized that, once optimized for brain and cervical acquisition, 4D flow MRA will provides quantitative information not available with other routinely available dynamic MR sequences. The main goal of this study is to demonstrate the feasibility of a non-invasive evaluation of hemodynamics (quantitative speed measurements and flow tracking) in neuro applications using the 4D Flow prototype. The secondary goal is to compare parameters derived from 4D Flow prototype using two post-processing pipelines. 4D Flow images will be compared to other available hemodynamic information obtained as part of the routine clinical care in order to assess whether additional clinically relevant information can be extracted. The study of the arterio-venous deformations and the study of the supraaortic trunks require the realization of MRI sequences with injection of Gd during a clinical protocol of routine. The sequence added at the end of protocol does not modify the injection with clinical purpose.