Article Figures & Data
Figures
- FIGURE 1.
Quantitative assessment of gating-error magnitude. (Left) Normalized count density is shown across each frame of cardiac cycle for 3 example patients, demonstrating no or minor gating error, moderate gating error, and severe gating error. Gating-error magnitude was quantified by percentage of area that fell below 90% line but above intensity–time curve (shaded; 0% for none or minor, 0.9% for moderate, and 5.9% for severe). (Right) Count projection curves for same 3 patients using Emory Cardiac Toolbox, which reported gating error as none or minor (green), moderate (yellow), and severe (red). Ave = average.
- FIGURE 2.
Modeling of PSD in presence of gating error. Multiparameter model (PSD = [0.40] × [true PSD]1.2 × e(−severity/4.6) + 4.3) describes drop in PSD occurring with both simulated and pacing-induced gating error. Data from simulation studies are pooled from 12 patients, using each of 5 simulated severities of gating error per patient.
- FIGURE 3.
Prevalence and influence of gating error on PSD in our 64-patient cohort. Bars represent frequency of gating error at each level of severity; each bar is stratified by Emory Cardiac Toolbox’s report of gating error (green, none or minor; yellow, moderate; and red, severe). Overlain is PSD for each group (mean ± SE).
- FIGURE 4.
Post hoc correction of gating error in 1 patient. (A–C) Phase histograms from normal sinus rhythm study (A), pacemaker-induced gating-error study before application of correction algorithm (B), and pacemaker-induced gating-error study after application of correction algorithm (C). Each histogram shows percentage of myocardium (y-axis) contracting at each phase of cardiac cycle (x-axis). (D) Count drop-off pattern occurring with pacing-induced gating-error study; correction raises counts in frames with drop-off to values comparable to baseline.
Tables
Severity Gating error Change in PSD P vs. baseline 1 0.1% ± 0.1% −11.8% ± 7.7% 0.01 2 0.8% ± 0.2% −23.5% ± 9.4% 0.001 3 2.4% ± 0.4% −41.0% ± 12.2% <0.001 4 6.3% ± 0.3% −57.2% ± 11.8% <0.001 5 12.9% ± 0.3% −69.2% ± 9.2% <0.001 Patient no. Baseline PSD Induced gating error Induced gating error PSD Corrected PSD 1 70.3° 5.0% 28.5° 64.8° 2 52.2° 5.0% 17.6° 54.9° 3 14.7° 11.2% 6.4° 18.0° 4 49.3° 7.1% 17.7° 59.3° 5 62.8° 3.8% 23.1° 64.2° Average 49.9° ± 21.4° 6.4% ± 2.9% 18.7° ± 8.2° 52.2° ± 19.6° P vs. baseline 0.007 0.64
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