Evaluation of Data-Driven Rigid Motion Correction in Clinical Brain PET Imaging

Head motion during brain PET imaging can significantly degrade the quality of the reconstructed image, leading to reduced diagnostic value and inaccurate quantitation. A fully data-driven motion correc-tion approach was recently demonstrated to produce highly accurate motion estimates (<1 mm) with high temporal resolution (>= 1 Hz), which can then be used for a motion-corrected reconstruction. This can be applied retrospectively with no impact on the clinical image acquisition protocol. We present a reader-based evaluation and an atlas-based quantitative analysis of this motion correction approach within a clinical cohort. Methods: Clinical patient data were collected over 2019-2020 and processed retrospectively. Motion was estimated using image-based registration on reconstructions of ultrashort frames (0.6-1.8 s), after which list-mode reconstructions that were fully motion-corrected were performed. Two readers graded the motion -corrected and uncorrected reconstructions. An atlas-based quantita-tive analysis was performed. Paired Wilcoxon tests were used to test for significant differences in reader scores and SUVs between recon-structions. The Levene test was used to determine whether motion correction had a greater impact on quantitation in the presence of motion than when motion was low. Results: Fifty standard clinical 18F-FDG brain PET datasets (age range, 13-83 y; mean +/- SD, 59 +/- 20 y; 27 women) from 3 scanners were collected. The reader study showed a significantly different, diagnostically relevant improvement by motion correction when motion was present (P = 0.02) and no impact in low-motion cases. Eight percent of all datasets improved from diagnos-tically unacceptable to acceptable. The atlas-based analysis demon-strated a significant difference between the motion-corrected and uncorrected reconstructions in cases of high motion for 7 of 8 regions of interest (P < 0.05). Conclusion: The proposed approach to data -driven motion estimation and correction demonstrated a clinically sig-nificant impact on brain PET image reconstruction.