Table 3

7T MRI in vivo studies including subjects with HD and premanifest HD

PaperImaging methodsParticipantsQuestionResults
Apple et al 37 Volumetric: inversion recovery T1-weighted acquisition; voxel size 1x1×1 mm; scan time 3:33 min
Phase imaging: GRE acquisition; voxel size 0.5×0.5×4 mm
Also 3T volumetric T1-weighted acquisition; scan time 6:18 min
Phase images constructed with fully automated phase unwrapping algorithm73
(originally 16 per group, with 6 excluded due to not tolerating MRI)
Do quantitative 7TMR phase measurements of 7T LFS within CN differ between groups?Higher CN LFS in premotor HD vs NC (sig).
Strong correlation between LFS and CAP score (R2=0.61, sig).
van Bergen et al 38 T1-weighted MP-RAGE acquisition; voxel size 0.6×0.6×0.6 mm; scan time 6:32 min
QSM: multiecho 3D GRE acquisition; voxel size 1x1×1 mm; scan time 6:12 min
QSM maps created in multiple steps; Laplacian-based phase unwrapping converted to frequency shift images (in hertz), inverse dipole calculation used to obtain susceptibility maps, values reported relative to reference region (CSF in lateral ventricles)71
R2* maps calculated using the power method74
Do groups show differences in magnetic susceptibility (proxy measure of iron deposition) in basal ganglia structures in vivo using QSM and R2* at 7T MRI?Increased magnetic susceptibility in CN and putamen (~2x (sig)) in pre-HD (correlation with CAP score and volume reductions).
Increased magnetic susceptibility in GB (sig) in pre-HD.
Decreased magnetic susceptibility in SN and hippocampus in pre-HD (sig).
Increased R2* values in CN and putamen in pre-HD (sig); R2*findings only in these two regions and effect size smaller.
Doan et al 75 3D T1-weighted GRE acquisition; voxel size 0.3×0.3×2 mm
3D T2*-weighted GRE acquisition; voxel size 0.25×0.25×0.5 mm
Also 3T T1-weighted volumetric acquisition; 164 slices; voxel size 1.1×1.0×1.0 mm
Textural features analysed in ROIs using a 3D Grey-Level Co-occurrence Matrix76
Are there textural differences in subcortical structures between groups?No sig diff between textural features in subcortical structures in pre-HD vs NC when Bonferroni applied (without correction sig diff in CN).
Sig diff between textural features in putamen in HD vs NC when Bonferroni applied (without correction sig diff in pallidum, CN, putamen,thalamus).
Drouin-Ouellet et al 77
NB/Expansive study using mouse model, 3T and 7T MRI and postmortem tissue analysis. 7T MRI part of paper examined here
LL-EPI F-SAIR ASL acquisition protocol; voxel size 2x2×4 mm
PSIR anatomical acquisition; voxel size 0.8×0.8×0.8 mm
Turbo field EPI (MR angiogram); 100 slices; 0.6×0.6×0.6 mm
Average aCBV (mL blood/100 mL tissue) and arterial transit time calculated using 2 compartment vascular kinetic model78
In 7T part:
Are differences in aCBV (representing changes in cerebral vasculature) seen between groups?Increase in cortical GM aCBV in HD (sig).
No correlation between aCBV and GM volume.
No difference in aCBV in caudate or putamen.
  • HD diagnostic criteria used: positive for HD mutation with ≥40 repeats.

  • *UHDRS motor subscale score ≤3. † UHDRS motor subscale score ≤15.

  • ‡UHDRS motor subscale score ≥5.

  • §UHDRS motor subscale score ≤5.

  • ¶No UHDRS motor score cut-off; pre-HD diagnostic criteria used: positive for HD mutation with ≥40 repeats.

  • 3D, three dimensional; aCBV, arterial cerebral blood volume; CAP score, CAG-Age Product Scaled score; CN, caudate nucleus; CSF, cerebrospinal fluid; EPI, echo planar imaging; GM, grey matter; GP, globus pallidus; GRE, gradient echo sequence; HD, Huntington’s disease; LFS, local field shift (a measure of phase and proxy measure of iron deposition); LL-EPI F-SAIR ASL, Look-Locker echo planar imaging flow-sensitive alternating inversion recovery arterial spin labelling (used to generate arterial cerebral blood volume maps); MP2-RAGE, magnetisation-prepared 2 rapid acquisition gradient echo; NC, cognitively normal controls; pre-HD, premanifest HD; PSIR, phase-sensitive inversion recovery; R2*, apparent spin–spin relaxation rate; sig, significant (p<0.05); SN, substantia nigra; UHDRS, Unified Huntington’s Disease Rating Scale.