On the accuracy and reproducibility of a novel probabilistic atlas-based generation for calculation of head attenuation maps on integrated PET/MR scanners
Author(s)Chen, Kevin T.; Izquierdo-Garcia, David; Poynton, Clare B.; Chonde, Daniel B.; Catana, Ciprian
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Purpose To propose an MR-based method for generating continuous-valued head attenuation maps and to assess its accuracy and reproducibility. Demonstrating that novel MR-based photon attenuation correction methods are both accurate and reproducible is essential prior to using them routinely in research and clinical studies on integrated PET/MR scanners. Methods Continuous-valued linear attenuation coefficient maps (“μ-maps”) were generated by combining atlases that provided the prior probability of voxel positions belonging to a certain tissue class (air, soft tissue, or bone) and an MR intensity-based likelihood classifier to produce posterior probability maps of tissue classes. These probabilities were used as weights to generate the μ-maps. The accuracy of this probabilistic atlas-based continuous-valued μ-map (“PAC-map”) generation method was assessed by calculating the voxel-wise absolute relative change (RC) between the MR-based and scaled CT-based attenuation-corrected PET images. To assess reproducibility, we performed pair-wise comparisons of the RC values obtained from the PET images reconstructed using the μ-maps generated from the data acquired at three time points. Results The proposed method produced continuous-valued μ-maps that qualitatively reflected the variable anatomy in patients with brain tumor and agreed well with the scaled CT-based μ-maps. The absolute RC comparing the resulting PET volumes was 1.76 ± 2.33 %, quantitatively demonstrating that the method is accurate. Additionally, we also showed that the method is highly reproducible, the mean RC value for the PET images reconstructed using the μ-maps obtained at the three visits being 0.65 ± 0.95 %. Conclusion Accurate and highly reproducible continuous-valued head μ-maps can be generated from MR data using a probabilistic atlas-based approach.
DepartmentHarvard University--MIT Division of Health Sciences and Technology
European Journal of Nuclear Medicine and Molecular Imaging
Springer Berlin Heidelberg
Chen, Kevin T., David Izquierdo-Garcia, Clare B. Poynton, Daniel B. Chonde, and Ciprian Catana. “On the Accuracy and Reproducibility of a Novel Probabilistic Atlas-Based Generation for Calculation of Head Attenuation Maps on Integrated PET/MR Scanners.” European Journal of Nuclear Medicine and Molecular Imaging 44, no. 3 (August 29, 2016): 398–407.
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