Table 1.
Demographic data.
Fig 1.
Axial T1 weighted MRI (left), 2-[18F]FDG PET (center) and statistical analysis (right) at the same level in standard anatomical space in two HD gene-expansion carriers (A, B), and a healthy control for comparison (C). Both patients and control had normal MRI. Patient A. 2-[18F]FDG PET SUVR is moderately abnormal with symmetrically decreased metabolism in the Striata (red arrows). Possibly compensatory increased metabolism in the left thalamus (white arrow). CAPS score 1,04. Patient B. 2-[18F]FDG PET SUVR show possibly abnormal metabolism with the impression of slight striatal metabolic reduction (red arrows) compared to the cortex although within normal range in the statistical map. CAPS score 0.91. The figure shows the range of abnormal 2-[18F]FDG PET uptake in patients with high CAPS scores. Note the enlargement of the third ventricle in patient A (orange arrow), that appear as a spurious SPM correlation (Table 5). The statistical maps (right) compare regional activity without PVC normalized to cerebellar activity to a group of age matched controls using (MI Neurology, Siemens) displayed in Z-scores with color scale shown.
Table 2.
Intracranial volume (ICV) corrected MRI volumes and Partial volume corrected (PVC) 2-[18F]FDG brain metabolism.
Fig 2.
Scatter plots showing the striatal metrics derived as the average of both sides of the MRI volume (%) corrected for intra cranial volume (A), the uncorrected 2-[18F]FDG uptake (SUVR) normalized to cerebellar cortex (B), and the partial volume corrected 2-[18F]FDG uptake (SUVR) normalized to cerebellar cortex (C) vs. the CAPS score. The regression lines were all significant and are shown with slope and r2. For comparisons controls are plotted in blue at CAPS score 0 showing mean +/- 2 SD. The measurement, marked in red, represents the participant, who without PVC is under the -2 SD.
Fig 3.
Plot of the difference in striatal 2-[18F]FDG PET SUVR with and without partial volume correction vs. the absolute striatal volume (mL) of both HD gene-expansion carriers (blue dots) and controls (red dots). The slope is -0.023, p = 0.01, one sided. The plot shows that the influence of partial volume correction is largest in objects with the smaller absolute MRI volumes. The variation of differences in striatal 2-[18F]FDG PET SUVR could signify the importance of other factors such as shape and location of the structure that may influence PVC performance. The four top values were eliminated as outliers and not included in the analysis.
Table 3.
Diagnostic accuracy for partial volume corrected 2-[18F]FDG PET SUVR and intracranial volume corrected MRI volume of bilateral striatum for the separation of controls and Huntington’s disease gene-expansion carriers.
Table 4.
Association between PVC 2-[18F]FDG PET SUVR and MRI volume, corrected for ICV.
Table 5.
SPM analysis of the negative correlation of normalized 2-[18F]FDG uptake to CAPs score in premanifest HD gene-expansion carriers.