Variability in Absolute Apparent Diffusion Coefficient Values across Different Platforms May Be Substantial: A Multivendor, Multi-institutional Comparison Study

Purpose: To determine whether and to what degree absolute apparent diffusion coefficient (ADC) values vary between different imagers, vendors, field strengths, and intraimager conditions. Materials and Methods: Informed consent and institutional review board approval were obtained. Diffusion-weighted (DW) images with nearly identical parameters were obtained at 1.5 and 3.0 T from 12 healthy volunteers at seven institutions by using 10 magnetic resonance (MR) imagers provided by four different vendors. ADC maps were generated from isotropic DW maps, and images with a b value of 0 sec/mm2 were generated by using in-house software. The mean pixel values for the brain tissues were calculated for evaluating the differences among coil systems, imagers, vendors, and magnetic field strengths. Results: The absolute ADC values of gray and white matter from the same vendor varied substantially: 4%–9% at 1.5 and 3.0 T. With the exception of one vendor, the intervendor variability at 1.5 T was as high as 7%. Moreover,...