Acute Stroke Imaging: Feasibility and Value of MR Angiography with High Spatial and Temporal Resolution for Vessel Assessment and Perfusion Analysis in Patients with Wake-up Stroke

作者：Seeger Achim^*; Klose Uwe; Poli Sven; Kramer Ulrich; Ernemann Ulrike; Hauser Till Karsten

来源：Academic Radiology, 2015, 22(4): 413-422.

DOI：10.1016/j.acra.2014.11.013

• MRA
• time-resolved MRA
• wake-up stroke
• thrombolysis
• MR perfusion

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 UP 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.

• 出版日期2015-4