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Multi-system repeatability and reproducibility of apparent diffusion coefficient measurement using an ice-water phantom

Malyarenko, D.; Galbán, C.J.; Londy, F.J.; Meyer, C.R.; Johnson, T.D.; Rehemtulla, A.; Ross, B.D.; Chenevert, T.L.

Journal of Magnetic Resonance Imaging: Jmri 37(5): 1238-1246

2013


ISSN/ISBN: 1522-2586
PMID: 23023785
DOI: 10.1002/jmri.23825
Accession: 036594806

To determine quantitative quality control procedures to evaluate technical variability in multi-center measurements of the diffusion coefficient of water as a prerequisite to use of the biomarker apparent diffusion coefficient (ADC) in multi-center clinical trials. A uniform data acquisition protocol was developed and shared with 18 participating test sites along with a temperature-controlled diffusion phantom delivered to each site. Usable diffusion weighted imaging data of ice water at five b-values were collected on 35 clinical MRI systems from three vendors at two field strengths (1.5 and 3 Tesla [T]) and analyzed at a central processing site. Standard deviation of bore-center ADCs measured across 35 scanners was <2%; error range: -2% to +5% from literature value. Day-to-day repeatability of the measurements was within 4.5%. Intra-exam repeatability at the phantom center was within 1%. Excluding one outlier, inter-site reproducibility of ADC at magnet isocenter was within 3%, although variability increased for off-center measurements. Significant (>10%) vendor-specific and system-specific spatial nonuniformity ADC bias was detected for the off-center measurement that was consistent with gradient nonlinearity. Standardization of DWI protocol has improved reproducibility of ADC measurements and allowed identifying spatial ADC nonuniformity as a source of error in multi-site clinical studies.

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