Test Suite

The simDRIFT test suite will run 20 DWI forward simulations to verify that simDRIFT’s core functionalities, physics, and output types and shapes are as expected. On an RTX3090, the test suite takes a few minutes to complete; however, this time will depend on your hardware. As a remark, the DWI forward simulations run here are relatively small-scale, and thus you may not notice a significant increase in GPU utilization while the test suite runs.

Test Signals and Trajectories,

• (1/20) Test Signal Types: assert that the forward simulated signal is a Nifti file.

• (2/20) Test Trajectory File Types: assert that the forward trajectory matrix is a .npy file.

• Test Signal Shapes: assert that the forward simulated signal shapes correspond to the input diffusion schemes.

  • (4/20)-DBSI-99-Direction

  • (5/20)-ABCD-103-Direction

  • (6/20)-NODDI-145-Direction

• (7/20) Test Custom bval/bvec files: assert that the forward simulated signal induced by a custom, input-supplied bvec and bval file matches the shapes from the specified custom diffusion scheme.

• Test Trajectory Shapes: assert that the forward simulated trajectory matrix matches the size of the input number of spins in the ensemble.

  • (8/20)-100 spins

  • (9/20)-256,000 spins

  • (10/20)-1,000,000 spins

Test Physics

• Test Water Physics: verify that the forward simulated water-only signal corresponds to a diffusion tensor matching the input water diffusivity parameter, and verify that this diffusion tensor is isotropic.

  • (11/20)- D_water = 3.0 \(\mu m^{2} / ms\) <-> AD = RD = 3.0 \(\mu m^{2} / ms\)

  • (12/20)- D_water = 2.0 \(\mu m^{2} / ms\) <-> AD = RD = 2.0 \(\mu m^{2} / ms\)

  • (13/20)- D_water = 1.0 \(\mu m^{2} / ms\) <-> AD = RD = 1.0 \(\mu m^{2} / ms\)

• Test Fiber Physics: verify that the forward simulated respective fiber-only signals corresponds to a diffusion tensor matching the input fiber diffusivity parameter, and verify that this diffusion tensor is anisotropic.

  • (14/20)- [D_fiber_1, D_fiber_2, D_fiber_3] = [1.0, 2.0, 2.0] ( \(\mu m^{2} / ms\)), and AD \(>>\) RD

  • (15/20)- [D_fiber_1, D_fiber_2, D_fiber_3] = [1.0, 1.5, 2.0] ( \(\mu m^{2} / ms\)), and AD \(>>\) RD

  • (16/20)- [D_fiber_1, D_fiber_2, D_fiber_3] = [1.0, 1.0, 1.5] ( \(\mu m^{2} / ms\)), and AD \(>>\) RD

• Test Cell Physics: verify that the forward simulated cell-only signal, at various cell radii, corresponds to an isotropic diffusion tensor

  • (17/20)- r = [1.0 \(\mu m\), 1.0 \(\mu m\)], AD = RD

  • (18/20)- r = [1.5 \(\mu m\), 1.5 \(\mu m\)], AD = RD

  • (19/20)- r = [2.0 \(\mu m\), 2.0 \(\mu m\)], AD = RD

• (20/20) Test Single Cell Physics: verify that the forward simulated cell-only signal, at various cell radii, corresponds to an isotropic diffusion tensor, r = [1.0 \(\mu m\)], AD = RD