Motion-Corrected Imaging of the Aortic Valve with 18F-NaF PET/CT and PET/MRI: A Feasibility Study.
Doris MK., Rubeaux M., Pawade T., Otaki Y., Xie Y., Li D., Tamarappoo BK., Newby DE., Berman DS., Dweck MR., Slomka PJ., Dey D.
We investigated whether motion correction of gated 18F-fluoride PET/CT and PET/MRI of the aortic valve could improve PET quantitation and image quality. Methods: A diffeomorphic, mass-preserving, anatomy-guided registration algorithm was used to align the PET images from 4 cardiac gates, preserving all counts, and apply them to the PET/MRI and PET/CT data of 6 patients with aortic stenosis. Measured signal-to-noise ratios (SNRs) and target-to-background ratios (TBRs) were compared with the standard method of using only the diastolic gate. Results: High-intensity aortic valve 18F-fluoride uptake was observed in all patients. After motion correction, SNR and TBR increased compared with the median diastolic gate (SNR, 51.61 vs. 21.0; TBR, 2.85 vs. 2.22) and the median summed data (SNR, 51.61 vs. 34.10; TBR, 2.85 vs. 1.95) (P = 0.028 for all). Furthermore, noise decreased from 0.105 (median, diastolic) to 0.042 (median, motion-corrected) (P = 0.028). Conclusion: Motion correction of hybrid 18F-fluoride PET markedly improves SNR, resulting in improved image quality.