title: High resolution CBV assessment with PEAK-EPI: k-t-undersampling and reconstruction in echo planar imaging.
abstract: Achieving higher spatial resolution and improved brain coverage while mitigating in-plane susceptibility artifacts in the assessment of perfusion parameters, such as cerebral blood volume, in echo planar imaging (EPI)-based dynamic susceptibility contrast weighted cerebral perfusion measurements.
  
  
  
  PEAK-EPI, an EPI sequence with interleaved readout trajectories and three different strategies for autocalibration-signal acquisition (inplace, dynamic extra and extra) is presented. Performance of each approach is analyzed in vivo based on flip angle variation induced dynamics, assessing temporal fidelity, temporal SNR and g-factors. All approaches are compared with conventional GRAPPA reconstructions. PEAK-EPI with inplace autocalibration-signal at R = 5 is then compared with the standard clinical EPI protocol in six patients, using two half-dose dynamic susceptibility contrast weighted cerebral perfusion measurements per subject.
  
  
  
  PEAK-EPI acquisition facilitates a substantial increase of spatial resolution at a higher number of slices per TR and provides improved SNR compared to conventional GRAPPA. High dependency of the resulting reconstruction quality on the type of autocalibration-signal acquisition is observed. PEAK-EPI with inplace autocalibration-signal achieves high temporal fidelity and initial feasibility is shown.
  
  
  
  The obtained high resolution cerebral blood volume maps reveal more detailed information than in corresponding standard EPI measurements and facilitate detailed delineation of tumorous tissue. Magn Reson Med 77:2153-2166, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Ramb
authors.affiliation: Department of Neuroradiology, University Medical Center, Freiburg, Germany.
authors.forename: Irina
authors.initials: I
authors.lastname: Mader
authors.affiliation: Institute of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Bern, Switzerland.
authors.forename: Bernd
authors.initials: B
authors.lastname: Jung
authors.affiliation: Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hennig
authors.affiliation: Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Maxim
authors.initials: M
authors.lastname: Zaitsev
mesh_terms: D000328:Adult; D000465:Algorithms; D001810:Blood Volume; D001811:Blood Volume Determination / Q000379:methods*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: DSC-MRI; EPI; GRAPPA; PEAK-GRAPPA; cerebral perfusion