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Automated movement correction for dynamic PET/CT images: evaluation with phantom and patient data.

Ye H, Wong KP, Wardak M, Dahlbom M, Kepe V, Barrio JR, Nelson LD, Small GW, Huang SC - PLoS ONE (2014)

Bottom Line: Image artifacts were significantly diminished after MC.There were significant differences (P<0.05) in the FDDNP DVR and FDG Ki values in the parietal and temporal regions after MC.In conclusion, MC applied to dynamic brain FDDNP and FDG PET/CT scans could improve the qualitative and quantitative aspects of images of both tracers.

View Article: PubMed Central - PubMed

Affiliation: Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.

ABSTRACT
Head movement during a dynamic brain PET/CT imaging results in mismatch between CT and dynamic PET images. It can cause artifacts in CT-based attenuation corrected PET images, thus affecting both the qualitative and quantitative aspects of the dynamic PET images and the derived parametric images. In this study, we developed an automated retrospective image-based movement correction (MC) procedure. The MC method first registered the CT image to each dynamic PET frames, then re-reconstructed the PET frames with CT-based attenuation correction, and finally re-aligned all the PET frames to the same position. We evaluated the MC method's performance on the Hoffman phantom and dynamic FDDNP and FDG PET/CT images of patients with neurodegenerative disease or with poor compliance. Dynamic FDDNP PET/CT images (65 min) were obtained from 12 patients and dynamic FDG PET/CT images (60 min) were obtained from 6 patients. Logan analysis with cerebellum as the reference region was used to generate regional distribution volume ratio (DVR) for FDDNP scan before and after MC. For FDG studies, the image derived input function was used to generate parametric image of FDG uptake constant (Ki) before and after MC. Phantom study showed high accuracy of registration between PET and CT and improved PET images after MC. In patient study, head movement was observed in all subjects, especially in late PET frames with an average displacement of 6.92 mm. The z-direction translation (average maximum = 5.32 mm) and x-axis rotation (average maximum = 5.19 degrees) occurred most frequently. Image artifacts were significantly diminished after MC. There were significant differences (P<0.05) in the FDDNP DVR and FDG Ki values in the parietal and temporal regions after MC. In conclusion, MC applied to dynamic brain FDDNP and FDG PET/CT scans could improve the qualitative and quantitative aspects of images of both tracers.

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Related in: MedlinePlus

TACs in both medial temporal region and cerebellum (the reference region), and Logan plot showed less fluctuation after MC for a subject who had large head movement during a dynamic FDDNP PET/CT scan.A. Comparisons of TACs before and after MC in medial temporal region. B. Comparisons of TACs before and after MC in cerebellum. C. The slope of the Logan plot increased by 7.5% after MC for this patient.
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pone-0103745-g009: TACs in both medial temporal region and cerebellum (the reference region), and Logan plot showed less fluctuation after MC for a subject who had large head movement during a dynamic FDDNP PET/CT scan.A. Comparisons of TACs before and after MC in medial temporal region. B. Comparisons of TACs before and after MC in cerebellum. C. The slope of the Logan plot increased by 7.5% after MC for this patient.

Mentions: Since the tissue TAC of FDDNP in the medial temporal region usually becomes linear later in time when plotted on a Logan plot, we used it to determine the time range which is 30–65 minutes for DVR image generation. Comparison of TACs before and after MC and their corresponding Logan plots for a medial temporal region in a patient is shown in Fig. 9. The TACs in both medial temporal region and cerebellum (the reference region), and Logan plot showed less fluctuation after MC. The slope of the Logan plot increased by 7.5% after MC in the medial temporal region for this patient. Improvement in the DVR image after MC is shown in Fig. 10A for a patient who had head rotations and translations. Reduction in artifacts in the medial temporal region, and in left-right asymmetry after MC was easily noticeable. The same study also showed better hemispheric separation, increased uptake in brain stem and occipital regions, and decreased uptake in frontal region after MC (Fig. 10B). In the FDDNP research patient study group, DVR values in the frontal lobe and medial temporal region were significantly different (P<0.05) before and after MC; the absolute value of difference of DVR before and after MC was 0.074 (6.9%) and 0.076 (6.6%), respectively (Fig. 11).


Automated movement correction for dynamic PET/CT images: evaluation with phantom and patient data.

Ye H, Wong KP, Wardak M, Dahlbom M, Kepe V, Barrio JR, Nelson LD, Small GW, Huang SC - PLoS ONE (2014)

TACs in both medial temporal region and cerebellum (the reference region), and Logan plot showed less fluctuation after MC for a subject who had large head movement during a dynamic FDDNP PET/CT scan.A. Comparisons of TACs before and after MC in medial temporal region. B. Comparisons of TACs before and after MC in cerebellum. C. The slope of the Logan plot increased by 7.5% after MC for this patient.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128781&req=5

pone-0103745-g009: TACs in both medial temporal region and cerebellum (the reference region), and Logan plot showed less fluctuation after MC for a subject who had large head movement during a dynamic FDDNP PET/CT scan.A. Comparisons of TACs before and after MC in medial temporal region. B. Comparisons of TACs before and after MC in cerebellum. C. The slope of the Logan plot increased by 7.5% after MC for this patient.
Mentions: Since the tissue TAC of FDDNP in the medial temporal region usually becomes linear later in time when plotted on a Logan plot, we used it to determine the time range which is 30–65 minutes for DVR image generation. Comparison of TACs before and after MC and their corresponding Logan plots for a medial temporal region in a patient is shown in Fig. 9. The TACs in both medial temporal region and cerebellum (the reference region), and Logan plot showed less fluctuation after MC. The slope of the Logan plot increased by 7.5% after MC in the medial temporal region for this patient. Improvement in the DVR image after MC is shown in Fig. 10A for a patient who had head rotations and translations. Reduction in artifacts in the medial temporal region, and in left-right asymmetry after MC was easily noticeable. The same study also showed better hemispheric separation, increased uptake in brain stem and occipital regions, and decreased uptake in frontal region after MC (Fig. 10B). In the FDDNP research patient study group, DVR values in the frontal lobe and medial temporal region were significantly different (P<0.05) before and after MC; the absolute value of difference of DVR before and after MC was 0.074 (6.9%) and 0.076 (6.6%), respectively (Fig. 11).

Bottom Line: Image artifacts were significantly diminished after MC.There were significant differences (P<0.05) in the FDDNP DVR and FDG Ki values in the parietal and temporal regions after MC.In conclusion, MC applied to dynamic brain FDDNP and FDG PET/CT scans could improve the qualitative and quantitative aspects of images of both tracers.

View Article: PubMed Central - PubMed

Affiliation: Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.

ABSTRACT
Head movement during a dynamic brain PET/CT imaging results in mismatch between CT and dynamic PET images. It can cause artifacts in CT-based attenuation corrected PET images, thus affecting both the qualitative and quantitative aspects of the dynamic PET images and the derived parametric images. In this study, we developed an automated retrospective image-based movement correction (MC) procedure. The MC method first registered the CT image to each dynamic PET frames, then re-reconstructed the PET frames with CT-based attenuation correction, and finally re-aligned all the PET frames to the same position. We evaluated the MC method's performance on the Hoffman phantom and dynamic FDDNP and FDG PET/CT images of patients with neurodegenerative disease or with poor compliance. Dynamic FDDNP PET/CT images (65 min) were obtained from 12 patients and dynamic FDG PET/CT images (60 min) were obtained from 6 patients. Logan analysis with cerebellum as the reference region was used to generate regional distribution volume ratio (DVR) for FDDNP scan before and after MC. For FDG studies, the image derived input function was used to generate parametric image of FDG uptake constant (Ki) before and after MC. Phantom study showed high accuracy of registration between PET and CT and improved PET images after MC. In patient study, head movement was observed in all subjects, especially in late PET frames with an average displacement of 6.92 mm. The z-direction translation (average maximum = 5.32 mm) and x-axis rotation (average maximum = 5.19 degrees) occurred most frequently. Image artifacts were significantly diminished after MC. There were significant differences (P<0.05) in the FDDNP DVR and FDG Ki values in the parietal and temporal regions after MC. In conclusion, MC applied to dynamic brain FDDNP and FDG PET/CT scans could improve the qualitative and quantitative aspects of images of both tracers.

Show MeSH
Related in: MedlinePlus