title: Technical Note: A safe, cheap, and easy-to-use isotropic diffusion MRI phantom for clinical and multicenter studies.
abstract: OBJECTIVE
  Since Diffusion Weighted Imaging (DWI) data acquisition and processing are not standardized, substantial differences in DWI derived measures such as Apparent Diffusion Coefficient (ADC) may arise which are related to the acquisition or MRI processing method, but not to the sample under study. Quality assurance using a standardized test object, or phantom, is a key factor in standardizing DWI across scanners.
  
  
  METHODS
  Current diffusion phantoms are either complex to use, not available in larger quantities, contain substances unwanted in a clinical environment, or are expensive. A diffusion phantom based on a polyvinylpyrrolidone (PVP) solution, together with a phantom holder, is presented and compared to existing diffusion phantoms for use in clinical DWI scans. An ADC vs. temperature calibration curve was obtained.
  
  
  RESULTS
  ADC of the phantom (808 to 857 ± 0.2 mm2/s) is in the same range as ADC values found in brain tissue. ADC measurements are highly reproducible across time with an intra-class correlation coefficient of > 0.8. ADC as function of temperature (in Kelvin) can be estimated as ADCm(T)=[exp(-7.09)·exp-2903.81T-1293.55] with a total uncertainty (95% confidence limit) of ± 1.7%.
  
  
  CONCLUSIONS
  We present an isotropic diffusion MRI phantom, together with its temperature calibration curve, that is easy-to-use in a clinical environment, cost-effective, reproducible to produce, and that contains no harmful substances.
authors.affiliation: Department of Radiology, University Hospital Antwerp & University of Antwerp, 2650, Edegem, Belgium.
authors.forename: Pim
authors.initials: P
authors.lastname: Pullens
authors.affiliation: iMinds - Vision Lab, Department of Physics, University of Antwerp, 2610, Antwerp, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Bladt
authors.affiliation: iMinds - Vision Lab, Department of Physics, University of Antwerp, 2610, Antwerp, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Sijbers
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp & University of Antwerp, 2650, Edegem, Belgium.
authors.forename: Andrew I R
authors.initials: AI
authors.lastname: Maas
authors.affiliation: Department of Radiology, University Hospital Antwerp & University of Antwerp, 2650, Edegem, Belgium.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Parizel
mesh_terms: D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging; D002138:Calibration; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000191:economics / Q000295:instrumentation* / Q000379:methods / Q000592:standards*; D006801:Humans; D008962:Models, Theoretical; D015337:Multicenter Studies as Topic / Q000191:economics / Q000295:instrumentation* / Q000379:methods / Q000592:standards*; D019047:Phantoms, Imaging / Q000191:economics; D011205:Povidone; D011785:Quality Assurance, Health Care / Q000191:economics / Q000379:methods; D015203:Reproducibility of Results; D012996:Solutions; D013696:Temperature; D013997:Time Factors; D066127:White Matter / Q000000981:diagnostic imaging
chemical_list: D012996:Solutions; D011205:Povidone
keywords: diffusion tensor imaging; imaging; multicenter study; phantoms; quality control