Quantitative Study of Abdominal Blood Flow Patterns in Patients with Aortic Dissection by 4-Dimensional Flow MRI

Dongting Liu,Zhanming Fan,Jiayi Liu,Aurélien F. Stalder,Jing An,Nan Zhang,Yu Li,Zhonghua Sun,Andreas Greiser

doi:10.1038/s41598-018-27249-9

Abstract

The purpose of this study is to evaluate the hemodynamic characteristics of the true lumen (TL) and the false lumen (FL) in 16 patients with aortic dissection (AD) using 4D flow magnetic resonance imaging (MRI) and thoracic and abdominal computed tomography (CT) angiography. The quantitative parameters that were measured in the TL and FL included velocity and flow. The mean area and regurgitant fraction of the TL were significantly lesser at all four levels (p < 0.05); the average through-plane velocity, peak velocity magnitude, average net flow, peak flow, and net forward volume in the TL were considerably higher (p < 0.05). The intimal entry’s size was negatively correlated with the blood flow velocity and flow rate in the TL (p < 0.05) and positively correlated with the average through-plane velocity, average net flow, and peak flow in the FL (p < 0.05); the blood flow indices in the TL were enhanced with an increase in the intimal entry numbers (p < 0.05) and the peak flow in the FL was lowered (p = 0.025); if FL thrombosis existed, the average through-plane velocity and peak velocity magnitude in the TL were substantially higher (p < 0.05). 4D flow MRI facilitates qualitative and quantitative analysis of the alterations in the abdominal aortic blood flow patterns.

Highlights

In recent years, noninvasive imaging techniques, such as multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) have largely replaced conventional angiography for the diagnosis of AD9,10
Type A aortic dissection (AD) was diagnosed in one patient with the intimal tear being present in the ascending aorta, while type B was noticed in the rest of the patients with the tear being located at the distal end of the left subclavian artery or in the descending aorta
We investigated the clinical application of 4D-flow MRI imaging for the qualitative and quantitative analysis of the flow alterations in the true lumen (TL) and false lumen (FL) of abdominal aortic dissections

Summary

Introduction

Noninvasive imaging techniques, such as multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) have largely replaced conventional angiography for the diagnosis of AD9,10. MDCT possesses a high spatial resolution, thereby facilitating an excellent anatomic visualization of AD; it is a modality that relies on ionizing radiation and fails to provide hemodynamic information pertaining to the TL and FL. MRI holds many advantages over CT for studying the morphology and hemodynamics of cardiovascular diseases. Two-dimensional phase contrast MRI (2D PC-MRI) is capable of revealing the flow pattern differences in the true and false lumina[11–13]. Data from previous investigations suggest that variations in flow patterns and hemodynamics may play an important role in predicting the complications and determining the outcomes of AD. Improved Cartesian[14] and radial[15] four-dimensional (4D) flow-sensitive velocity mapping techniques (4D flow MRI) have been introduced for the evaluation of flow patterns. True lumen False lumen Overriding True lumen False lumen Overriding No Yes No Yes No Yes interventional procedures open chest surgery

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