Article Figures & Data
Figures
- FIG 1.
[18F]-FDOPA brain PET and fused [18F]-FDOPA brain PET/MR imaging at a standard 20-minute acquisition time. The healthy subject (A and B) demonstrates the characteristic “comma sign” uptake in the striatum. The subject with abnormal findings (C and D) demonstrates marked loss of uptake in the bilateral striatum, particularly involving the bilateral putamina and left > right caudate nuclei, corresponding to more extensive right-sided clinical deficits.
- FIG 2.
Normal findings on [18F]-FDOPA AC PET at 5-minute (A), 10-minute (B), 15-minute (C), and 20-minute (D) acquisition times. Note that image-quality ratings were stable following 15 minutes, and between-subject abnormality detection rates were highly consistent between the 2 readers when using 10-, 15-, or 20-minute acquisition times but were inconsistent at 5 minutes.
- FIG 3.
Abnormal findings on [18F]-FDOPA AC PET at 5-minute (A), 10-minute (B), 15-minute (C), and 20-minute (D) acquisition times. Note that image-quality ratings were stable following 15 minutes, and between-subject abnormality detection rates were highly consistent between the 2 readers when using 10-, 15-, or 20-minute acquisition times but were inconsistent at 5 minutes.
Tables
CT Parameters PET Parameters Kilovolt (peak) 120 Acquisition (1-bed) 20-Min static acquired in list mode Max mA (auto mA off) 95 Reconstruction VUE Point FXb Noise index NA Matrix 192 × 192 CT section thickness (mm) 3.75 Iterations 2 Rotation (sec) 0.8 Subsets 32 Pitch (mm/rot) 1.375 Z-axis filter Heavy FOV (cm) 50 Postfilter (mm, FWHM) 4 FOV (cm) 30 - Table 2:
Demographic characteristics for subjects (n = 20) stratified by neuroradiologist expert read results at the standard 20-minute acquisition time
Characteristic Whole Sample (n = 20) Expert Rated Scan Findings as Abnormal (n = 10) Expert Rated Scan Findings as Normal (n = 10) P Value Age (yr) 65.6 (14.9) 62.8 (17.4) 68.4 (12.3) .402 Female (%) 55.0 40.0 70.0 .189 Clinical history Tremor in hand/leg (%) 60.0 70.0 50.0 .361 PD (%) 15.0 30.0 0.0 .060 Right unilateral (%) 10.0 10.0 10.0 1.000 Left unilateral (%) 20.0 30.0 10.0 .264 Bilateral (%) 20.0 20.0 20.0 1.000 Bradykinesia (%) 25.0 50.0 0.0 .010 - Table 3:
Reader confidence and image quality scores stratified by neuroradiologist expert read results at the standard 20-minute acquisition timea
Whole Sample (n = 20) Expert Rated Scan Findings as Abnormal (n = 10) Expert Rated as Scan Findings as Normal (n = 10) P Value Confidence score (mins) 20 1.6 (1.4) 2.9 (0.8) 0.4 (0.5) <.001 15 1.8 (1.4) 3 (0.7) 0.6 (0.5) <.001 10 2 (1.5) 3.3 (0.7) 0.7 (0.9) <.001 5 2.2 (1.3) 3 (0.9) 1.4 (1) .001 Image quality (mins) 20 2.2 (0.7) 1.8 (0.7) 2.6 (0.6) .003 15 2.2 (0.8) 1.8 (0.7) 2.6 (0.6) .004 10 2 (0.9) 1.6 (0.7) 2.5 (0.8) .006 5 1.7 (0.8) 1.3 (0.5) 2.2 (0.9) .009 ↵a No differences between scans with abnormal and normal findings were statistically significant as determined using nonparametric trend tests.
- Table 4:
Measures of image-rating agreement and consistency across the 2 raters and the expert neuroradiologist read using different acquisition timesa
↵a Rank order agreement is shown in blue; intra-/interrater agreement across image ratings is shown in green. The correspondence of confidence scores to the expert neuroradiologist read completed at a standard 20-minute acquisition time is shown in shades of red across the diagonal. The strength of the association is reported by color gradations. Statistically significant associations evident after adjusting for the false discovery rate are shown in bold italicized typeface. The optimal cutoff for rater 1 compared with the expert rating included scans rated as equivocal, while the optimal cutoff for rater 2 compared with expert raters included only those with a probable abnormal finding and above.
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