title: Pilot study of Iopamidol-based quantitative pH imaging on a clinical 3T MR scanner.
abstract: OBJECTIVE
  The objective of this study was to show the feasibility to perform Iopamidol-based pH imaging via clinical 3T magnetic resonance imaging (MRI) using chemical exchange saturation transfer (CEST) imaging with pulse train presaturation.
  
  
  METHODS
  The pulse train presaturation scheme of a CEST sequence was investigated for Iopamidol-based pH measurements using a 3T magnetic resonance (MR) scanner. The CEST sequence was applied to eight tubes filled with 100-mM Iopamidol solutions with pH values ranging from 5.6 to 7.0. Calibration curves for pH quantification were determined. The dependence of pH values on the concentration of Iopamidol was investigated. An in vivo measurement was performed in one patient who had undergone a previous contrast-enhanced computed tomography (CT) scan with Iopamidol. The pH values of urine measured with CEST MRI and with a pH meter were compared.
  
  
  RESULTS
  In the measured pH range, pH imaging using CEST imaging with pulse train presaturation was possible. Dependence between the pH value and the concentration of Iopamidol was not observed. In the in vivo investigation, the pH values in the human bladder measured by the Iopamidol CEST sequence and in urine were consistent.
  
  
  CONCLUSIONS
  Our study shows the feasibility of using CEST imaging with Iopamidol for quantitative pH mapping in vitro and in vivo on a 3T MR scanner.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany, Anja.Lutz@med.uni-duesseldorf.de.
authors.forename: Anja
authors.initials: A
authors.lastname: Müller-Lutz
authors.forename: Nadia
authors.initials: N
authors.lastname: Khalil
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schmitt
authors.forename: Vladimir
authors.initials: V
authors.lastname: Jellus
authors.forename: Gael
authors.initials: G
authors.lastname: Pentang
authors.forename: Georg
authors.initials: G
authors.lastname: Oeltzschner
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.forename: Rotem S
authors.initials: RS
authors.lastname: Lanzman
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Wittsack
mesh_terms: D000465:Algorithms; D003287:Contrast Media / Q000032:analysis / Q000737:chemistry; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007479:Iopamidol / Q000032:analysis / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008875:Middle Aged; D019047:Phantoms, Imaging; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D001743:Urinary Bladder / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D007479:Iopamidol