title: Scan-rescan reproducibility of parallel transmission based amide proton transfer imaging of brain tumors.
abstract: OBJECTIVE
  To evaluate the reproducibility of amide proton transfer (APT) imaging of brain tumors using a parallel transmission-based technique.
  
  
  METHODS
  Thirteen patients with brain tumors (four low-grade gliomas, three glioblastoma multiforme, five meningiomas, and one malignant lymphoma) were included in the study. APT imaging was conducted at 3T using a 2-channel parallel transmission scheme with a saturation time of 2 seconds and B1 amplitude of 2 μT. A 2D fast spin-echo sequence with driven-equilibrium refocusing was used for imaging. Z-spectra were obtained at 25 frequency offsets from -6 to +6 ppm (step 0.5 ppm). A point-by-point B0 correction was performed with a B0 map. A scan-rescan reproducibility test was performed in two sessions on separate days for each patient. The interval between the two sessions was 4.8 ± 3.5 days. Regions-of-interest (ROIs) were placed to include the whole tumor for each case. A mean and 90-percentile value of APT signal for the whole tumor histogram was calculated for each session. The between-session and within-session reproducibility was evaluated using linear regression analysis, intraclass correlation coefficient (ICC), and a Bland-Altman plot.
  
  
  RESULTS
  The mean and 90-percentile values of the APT signal for whole tumor ROI showed excellent agreements between the two sessions, with R(2) of 0.91 and 0.96 in the linear regression analysis and ICC of 0.95 and 0.97, respectively.
  
  
  CONCLUSIONS
  Parallel transmission-based APT imaging of brain tumors showed good reproducibility.
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Togao
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Hiwatashi
authors.affiliation: Philips Research Europe, Hamburg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Keupp
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yamashita
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Kikuchi
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
authors.affiliation: Philips Electronics Japan, Tokyo, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Philips Research Europe, Hamburg, Germany.
authors.forename: Marijn J
authors.initials: MJ
authors.lastname: Kruiskamp
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.|Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Koji
authors.initials: K
authors.lastname: Sagiyama
authors.affiliation: Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Masaya
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000465:Algorithms; D000577:Amides; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000577:Amides; D011522:Protons
keywords: amide proton transfer (APT) imaging; chemical exchange saturation transfer (CEST); glioma; reproducibility; rescan test; scan