Influence of different time framings, reconstruction algorithms and post-processing methods on the quantification of myocardial blood flow from 13N-NH3 PET images

Background

The aim was to investigate to what extent the quantification of myocardial blood flow (MBF) from dynamic ¹³N-NH₃ positron emission tomography (PET) images is affected by time frame schemes, time-of-flight (ToF), reconstruction algorithms, blood pool volume of interest (VOI) locations and compartment models in patients with suspected chronic coronary syndrome.

Methods

A standard MBF value was determined from 25 patients' rest/stress ¹³N-NH₃ PET/CT images reconstructed with ordered subset expectation maximization (OSEM), 5 s time frame for the first frames without ToF, subsequently analyzed using a basal VOI and the deGrado compartment model. MBFs calculated using 2 or 10 s for the first frames, ToF, block-sequential regularized expectation maximization (BSREM), apical or large VOI, Hutchins or Krivokapich compartment models were compared to MBF_standard in Bland–Altman plots (bias ± SD).

Results

Good agreement in global rest/stress MBF (mL/min/g) was found when changing the time frame scheme or reconstruction algorithm (MBF_standard vs. MBF_2s: −0.02 ± 0.06; MBF_10s: 0.01 ± 0.07; MBF_BSREM: 0.01 ± 0.07), while a lower level of agreement was found when altering the other factors (MBF_standard vs. MBF_ToF: −0.07 ± 0.10; MBF_{apical VOI}: −0.27 ± 0.25; MBF_{large VOI}: −0.11 ± 0.10; MBF_Hutchins: −0.08 ± 0.10; MBF_Krivokapich: −0.47 ± 0.50).

Conclusions

Quantification of MBF from ¹³N-NH₃ PET images is more affected by choice of compartment models, ToF and blood pool VOIs than by different time frame schemes and reconstruction algorithms.