Summary

This paper is the result of the “Diffusion MRI Harmonisation Challenge”, organized at the MICCAI 2017 CDMRI workshop. It presents a benchmark of 5 dMRI harmonisation algorithms, using a dataset of 14 participants scanned on 3 systems of different gradient strengths (40, 80 and 300 mT/m). In addition to the standard protocol, a state-of-the-art protocol was used with 2 of the 3 systems.

Dataset

  • 14 subjects split into trainset (9), validset (1) and testset (4)

  • Standard protocol : 30 gradient directions, 2.4mm iso
  • State-of-the-art protocol : 60 gradient directions, 1.5/1.2mm iso

Experiments

  1. Map the 40 mT/m standard signal to the 80 and 300 mT/m standard signals
  2. Map the 40 mT/m standard signal to the 80 and 300 mT/m state-of-the-art signals

The predicted signal is fitted with DTI to extract FA and MD maps. RISH features for order 0 and 2 are also computed.

Benchmarked methods

SHNet:

SHResNet:

SphericalNet:

FCSNet:

SDL:

Reference method : simple trilinear interpolation in the spatial domain, and spherical harmonics interpolation (order 6 for ST and 8 for SA) in the angular domain.

Results