Can intracranial time-of-flight-MR angiography predict extracranial carotid artery stenosis?

Filiz Osmanodja,Kersten Villringer,Jan F Scheitz,Jochen B Fiebach,Ramanan Ganeshan

doi:10.1007/s00415-021-10876-0

Abstract

ObjectivesExtracranial stenosis of the internal carotid artery (ICA) is an important cause of ischemic stroke and transient ischemic attack (TIA). It can be diagnosed using contrast-enhanced CT or MR angiography (MRA) as well as Doppler ultrasound. In this study, we assessed the diagnostic value of intracranial time-of-flight (TOF) MRA to predict extracranial ICA stenosis (ICAS).MethodsWe retrospectively analyzed consecutive patients with acute ischemic stroke or TIA and middle- (50–69%) or high-grade (70–99%) unilateral extracranial ICAS according to NASCET criteria assessed by ultrasound between January 2016 and August 2018. The control group consisted of patients without extracranial ICAS. Intraluminal signal intensities (SI) of the intracranial ICA on the side of the extracranial stenosis were compared to the contralesional side on TOF-MRA source images. SI ratios (SIR) of contralesional:lesional side were compared between groups.ResultsIn total, 151 patients were included in the main analysis. Contralesional:lesional SIR in the intracranial C4-segment was significantly higher in patients with ipsilateral extracranial ICA stenosis (n = 51, median 74 years, 57% male) compared to the control group (n = 100, median 68 years, 48% male). Mean SIR was 1.463 vs. 1.035 (p < 0.001) for right-sided stenosis and 1.362 vs. 1.000 (p < 0.001) for left-sided stenosis. Receiver-operating characteristic curve demonstrated a cut-off value of 1.086 for right-sided [sensitivity/specificity 75%/81%; area under the curve (AUC) 0.81] and 1.104 for left-sided stenosis (sensitivity/specificity 70%/84%; AUC 0.80) in C4 as a good predictor for high-grade extracranial ICAS.ConclusionsSIR on TOF-MRA can be a marker of extracranial ICAS.

Highlights

Extracranial internal carotid artery (ICA) stenoses constitute common and relevant causes of ischemic stroke
Inclusion criterion was presence of a middle- (50–69%) or high-grade (> 70%) extracranial ICA stenosis (ICAS) according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria [10] detected by ultrasound
For CE-MR angiography (MRA), a fixed bolus of 5 ml Gadovist® was administered at a flow rate of 5 ml/s, which was well tolerated in all patients reported

Summary

Introduction

Extracranial internal carotid artery (ICA) stenoses constitute common and relevant causes of ischemic stroke. Patients with middle- or high-grade stenosis (> 50%) are more likely to experience worse functional outcome and early stroke recurrence than patients with no or low-grade (< 50%) stenosis [1, 2]. In patients with high-grade (70–99%) extracranial ICA stenosis (ICAS), timely intervention can prevent recurrent ischemic stroke [3]. Timely identification of ipsilateral symptomatic ICAS is of clinical relevance. Doppler ultrasound (US) is a commonly accepted and accessible method in diagnosing extracranial ICAS. It has its drawbacks as well, that are investigator and experience dependency. In most comprehensive stroke centers, CT angiography (CTA) is still the primary examination in the emergency setting in

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