Rationale and Objectives
Magnetic resonance (MR) imaging (MRI) provides information that can be used to estimate
the symptom onset in patients with wake-up stroke (WUS). Time-resolved MR angiography
(MRA) is the fastest available MR sequence technique for vessel assessment, and the
different phases acquired can provide information about cerebral perfusion. The aim
of this study was to evaluate the diagnostic performance of time-resolved MRA both
for the assessment of vessel morphology and for the feasibility of perfusion.
Materials and Methods
Nineteen patients with WUS were included. Image quality and vessel pathologies were
evaluated and correlated to time-of-flight–MRA (n = 14), computed tomography–angiography (n = 4), sonography (n = 12), and conventional angiography (n = 6). The temporal delay of signal enhancement in all pixels of the time-resolved
MRA measurement after contrast injection was evaluated and compared to dynamic susceptibility
contrast-enhanced (DSC) perfusion imaging (n = 13).
Results
Time-resolved MRA resulted in the diagnosis of large vessel disease in 14 of 19 patients,
involving the internal carotids (n = 4), the vertebral arteries (n = 3), and the circle of Willis (n = 10). All severe vascular pathologies which influence patients' acute stroke therapy
were obtained by time-resolved MRA. Overestimation of stenoses in two of 14 patients
resulted in sensitivity and specificity of 100% and 71%, respectively. Time-to-peak
(TTP) estimations were hampered by movement artifacts in four patients (31%). Compared
to DSC, the area of TTP delay was comparable in size and localization without relevant
overestimation or underestimation.
Conclusions
Time-resolved MRA is a valuable technique in patients with WUS with high sensitivity
and high negative predictive value. Cerebral perfusion estimation can be performed
in selected cases for therapy decision but can be hampered by patient movement.
Key Words
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Article info
Publication history
Published online: January 16, 2015
Accepted:
November 29,
2014
Received:
September 5,
2014
Footnotes
Conflicts of Interest: The authors declare that they have no conflicts of interest.
Funding Source: There was no external funding for the study.
Identification
Copyright
© 2015 AUR. Published by Elsevier Inc. All rights reserved.
