Intracranial Flow Velocity Quantification Using Non-Contrast Four-Dimensional Flow MRI: A Prospective Comparative Study with Transcranial Doppler Ultrasound.

Sam-Yeol Ha,Moonjung Hwang,Jiyeon Baik,Yeonah Kang,Ho-Joon Lee,Seongho Park

doi:10.3390/diagnostics12010023

Abstract

Four-dimensional (4D) flow magnetic resonance imaging (MRI) allows three-dimensional velocity encoding to measure blood flow in a single scan, regardless of the intracranial artery direction. We compared blood flow velocity quantification by non-contrast 4D flow MRI and by transcranial Doppler ultrasound (TCD), the most widely used modality for measuring velocity. Twenty-two patients underwent both TCD and non-contrast 4D flow MRI. The mean time interval between TCD and non-contrast 4D flow MRI was 0.7 days. Subsegmental velocities were measured bilaterally in the middle cerebral and basilar arteries using TCD and non-contrast 4D flow MRI. Intracranial velocity measurements using TCD and non-contrast 4D flow MRI demonstrated a strong correlation in the bilateral M1, especially at the proximal segment (right r = 0.74, left r = 0.78; all p < 0.001). Mean velocities acquired with 4D flow MRI were approximately 8 to 10% lower than those acquired with TCD according to the location of M1. Intracranial arterial flow measurements estimated using non-contrast 4D flow MRI and TCD showed strong correlation. 4D flow MRI enables simultaneous assessment of vascular morphology and quantitative hemodynamic measurement, providing three-dimensional blood flow visualization. 4D flow MRI is a clinically useful sequence with a promising role in cerebrovascular disease.

Highlights

Intracranial velocity measurement is clinically important in cerebrovascular conditions such as ischemic stroke, vasospasm, and post-bypass surgery, and it provides valuable hemodynamic information in cases of aneurysm and neurodegenerative disease [1,2,3,4,5].Transcranial Doppler ultrasound (TCD), which transmits ultrasound waves through the skull and receives reflecting waves from moving red blood cells, has been widely used for noninvasive and real-time measurement of intracranial arteries [6]
Mean velocities acquired with non-contrast 4D flow magnetic resonance imaging (MRI) were approximately 8 to 10% lower than those acquired by using transcranial Doppler ultrasound (TCD) according to the location of M1
We observed that peak systolic velocityvelocity (PSV) had a larger measurement difference between the two modalities than end-diastolic velocity (EDV), which is thought to be owing to the temporal averaging effect of 4D flow MRI

Summary

Introduction

Intracranial velocity measurement is clinically important in cerebrovascular conditions such as ischemic stroke, vasospasm, and post-bypass surgery, and it provides valuable hemodynamic information in cases of aneurysm and neurodegenerative disease [1,2,3,4,5].Transcranial Doppler ultrasound (TCD), which transmits ultrasound waves through the skull and receives reflecting waves from moving red blood cells, has been widely used for noninvasive and real-time measurement of intracranial arteries [6]. Intracranial velocity measurement is clinically important in cerebrovascular conditions such as ischemic stroke, vasospasm, and post-bypass surgery, and it provides valuable hemodynamic information in cases of aneurysm and neurodegenerative disease [1,2,3,4,5]. TCD is limited in insonation angle correction for vascular direction as well as in accurate localization of vascular segments [7,8]. Standard two-dimensional phase-contrast MRI has gained attention as an alternative to TCD that can provide both vascular morphology information and quantitative measurements [9]. Recent developments of MR hardware and technique have enabled acquisition of volumetric time-resolved change over the cardiac cycle known as four-dimensional (4D) flow MRI; in other words, three-dimensional (3D) phase-contrast

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