The Number of Frames on ECG-Gated 18 F-FDG Small Animal PET Has a Significant Impact on LV Systolic and Diastolic Functional Parameters

Figures

• 

  Figure 1. Dynamic 18F-FDG PET images (a) and time activity curve (b) after tracer administration via the tail vein under hyperinsulinemic-euglycemic clamp conditions. Frame data from 15-35 min (stable left ventricular delineation phase) were used for subsequent ECG-gating functional analysis. Dynamic PET imaging revealed a time course with rapid clearance of administered 18F-FDG from the blood pool (<10 min), followed by stable tracer accumulation in the myocardium (>10 min). SA: short axis; HLA: horizontal long axis.

• 

  Figure 2. 18F-FDG PET images of a rat heart with no ECG-gated reconstruction (a) and with different ECG-gated frame numbers at end-diastolic (b) and end-systolic phases (c). SA: short axis; HLA: horizontal long axis; VLA: vertical long axis.

• 

  Figure 3. Example images of the edge detection of left ventricular wall and 3D images of the ventricular borders (a). Time-volume curves (b) and corresponding time-filling curve of the same animal with different numbers of gates per cardiac cycle. The smoothening of both curves due to the increasing number of volume values with increasing gate number is demonstrated as well as the calculation of the LV volumes and the PFR. EDV: end-diastolic volume; ESV: end-systolic volume; SV: stroke volume; EF: ejection fraction; PFR: peak filling rate.

• 

  Figure 4. Comparison of the LV volumes and functional parameters of all animals (ZDF diabetic animal = blue, ZL controls = red) with different numbers of frames per cardiac cycle using Holm-Sidak's multiple comparison test with 16 frame data as reference. The LV volumes (EDV, ESV, and SV) of the 4, 8, and 12 frame data differ significantly from the reference, whereas for EF and diastolic parameters (TPF, 1/3 FR, and PFR), no significant difference between the reconstruction with 12 gates per cycle and the reference was recorded. EDV: end-diastolic volume; ESV: end-systolic volume; SV: stroke volume; EF: ejection fraction; TPF: time to peak filling; 1/3FR: first third filling rate; PFR: peak filling rate. ∗,∗∗,∗∗∗,∗∗∗∗Statistically significant vs. 16 frames per cardiac cycle (P < 0.05, P < 0.005, P < 0.0005, P < 0.0001).

• 

  Figure 5. Impact of number of frames for diastolic parameters (PFR and 1/3 FR) between ZDF (diabetic rats) and ZL (control rats). For 16 frames per cardiac cycle, a significant difference was noted for both parameters (∗∗P < 0.005, far right), but not for 4, 8, and 12 frames per cycle.