title: A dialyzer-based flow system for validating dynamic contrast enhanced MR image acquisition.
abstract: OBJECTIVE
  Dynamic contrast enhanced magnetic resonance imaging (MRI) has proven to be quite sensitive for the characterization of masses and early response to therapy. However, it is fraught with a number of procedural challenges as well as a lack of standardization. In this article, we describe the use of a simple dialyzer-based flow system to evaluate reproducibility of dynamic contrast enhanced MRI under active flow conditions.
  
  
  METHODS
  The MR signal during a bolus injection of Gd-DTPA was analyzed to test the precision and variability of contrast agent kinetics during a typical dynamic contrast enhanced MRI sequence. A simple model allows an estimation of the washout rate constant of Gd-DTPA through the polysulfone tubules of the dialyzer.
  
  
  RESULTS
  The simple flow phantom described here provided reproducible measurements of the washout rate constants. The washout rate increased from 0.20 ± 0.005 min(-1) to 0.25 ± 0.008 min(-1) over 32 weeks. Measurements were also made at week 24 using dynamic computed tomography and found to be 0.27 ± 0.006 min(-1) . Overall, the computed tomography derived rate constants results were found be ∼12% higher than the corresponding MRI values.
  
  
  CONCLUSIONS
  In this study, we show that a simple dialyzer-based flow phantom can be used for testing dynamic contrast enhanced MRI pulse sequences and also allows for short-term reproducibility testing of rate constants.
authors.affiliation: Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, FDA, Silver Spring, Maryland, USA.
authors.forename: Sunder
authors.initials: S
authors.lastname: Rajan
authors.forename: Luke
authors.initials: L
authors.lastname: Herbertson
authors.forename: Marcelino
authors.initials: M
authors.lastname: Bernardo
authors.forename: Peter
authors.initials: P
authors.lastname: Choyke
mesh_terms: D003287:Contrast Media / Q000493:pharmacokinetics*; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D006435:Renal Dialysis / Q000295:instrumentation*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: DCE-MRI; dialyzer, polysulfone; flow-phantom
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