Journal
JOURNAL OF NUCLEAR MEDICINE
Volume 57, Issue 1, Pages 136-143Publisher
SOC NUCLEAR MEDICINE INC
DOI: 10.2967/jnumed.115.156299
Keywords
pseudo-CT; image synthesis; PET/MR; attenuation correction; GPU
Funding
- Consejeria de Educacion, Juventud y Deporte de la Comunidad de Madrid, through the Madrid-MIT M + Vision Consortium
- European Union
- Spanish Ministry of Economy and Competitiveness [TEC2012-39095-C03-01]
Ask authors/readers for more resources
Attenuation correction in hybrid PET/MR scanners is still a challenging task. This paper describes a methodology for synthesizing a pseudo-CT volume from a single T1-weighted volume, thus allowing us to create accurate attenuation correction maps. Methods: We propose a fast pseudo-CT volume generation from a patient-specific MR T1-weighted image using a groupwise patch-based approach and an MRI-CT atlas dictionary. For every voxel in the input MR image, we compute the similarity of the patch containing that voxel to the patches of all MR images in the database that lie in a certain anatomic neighborhood. The pseudo-CT volume is obtained as a local weighted linear combination of the CT values of the corresponding patches. The algorithm was implemented in a graphical processing unit (GPU). Results: We evaluated our method both qualitatively and quantitatively for PET/MR correction. The approach performed successfully in all cases considered. We compared the SUVs of the PET image obtained after attenuation correction using the patient-specific CT volume and using the corresponding computed pseudo-CT volume. The patient-specific correlation between SUV obtained with both methods was high (R-2 = 0.9980, P < 0.0001), and the Bland-Altman test showed that the average of the differences was low (0.0006 +/- 0.0594). A region-of-interest analysis was also performed. The correlation between SUVmean and SUVmax for every region was high (R-2 = 0.9989, P < 0.0001, and R-2 = 0.9904, P < 0.0001, respectively). Conclusion: The results indicate that our method can accurately approximate the patient-specific CT volume and serves as a potential solution for accurate attenuation correction in hybrid PET/MR systems. The quality of the corrected PET scan using our pseudo-CT volume is comparable to having acquired a patient-specific CT scan, thus improving the results obtained with the uttrashort-echo-time-based attenuation correction maps currently used in the scanner. The GPU implementation substantially decreases computational time, making the approach suitable for real applications.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available