The variability of mean ADC measurements with simultaneous multi-slice imaging in a NIST/QIBA diffusion phantom.

Motivation: Long MRI scan times limit patient throughput, degrades patient experience and can lead to motion that can have adverse effects on quantitative MRI measurements. Goal(s): Assess the impact of using simultaneous multi-slice (SMS) imaging on the accuracy and reproducibility of ADC measurements. Approach: The CaliberMRI diffusion phantom with full traceability through the National Institute of Standards and Technology (NIST) was imaged using a DWI sequence. Different SMS factors were applied in this multi-vendor study. Results: Mean ADC becomes less accurate and less reproducible as SMS factor increases. The highest errors were seen in solutions with the highest ADC values. Impact: Using SMS factors of 2 has the potential to speed up MRI DWI acquisitions without biasing ADC, improving patient experience and throughput while reducing motion artefacts. However, higher SMS factors may be unreliable, particularly at higher ADC values.