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  • Meeting abstract
  • Open Access

Impact of atlas-CT-based bone anatomy compensation on MR-based attenuation correction for brain PET imaging in a time-of-flight PET/MRI system: A direct comparison to a patient-CT-based approach

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EJNMMI Physics20152 (Suppl 1) :A68

  • Published:


  • Public Health
  • Gold
  • Gold Standard
  • Nuclear Medicine
  • Computational Mathematic

An atlas-CT-based bone-anatomy compensation for MR-based attenuation correction (MRAC) in brain PET/MRI imaging is a current standard. However, the impact of an anatomical difference has not been clinically evaluated. Thus, we aim to evaluate the impact of the anatomical dissimilarity on MRAC. Whole-body FDG-PET/CT followed by PET/MRI were performed for twelve patients in an integrated TOF PET/MRI system. The MRAC utilized an atlas-CT (MRAC-atlas) as well as a patient-specific-CT (MRAC patient) to produce AC maps (pseudo-CT). Instead of using atlas-CT, the MRAC-patient approach derived pseudo-CT from patient-specific-CT aligned to MR. For quantitative evaluation, CTAC was considered as gold standard for AC, and PET mean activity concentration values were measured and compared in eight 10 ml volumes-of-interest (VOI). PET activity concentration with MRAC, compared to CTAC, were systematically underestimated on average by 0.63±0.34 kBq/ml (4.0±2.2%) and 0.22±0.21 kBq/ml (1.4±1.5%) for the MRAC-atlas and the MRAC-patient, respectively: using the MRAC atlas, the error was increased to 0.41±0.25 kBq/ml (2.6±1.8%) on average (p≈0). However, the error increase was patient-dependent (highest: 5.7% vs. lowest: 0.3%) and VOI dependent (highest 3.1% vs. lowest: 1.9%). For the first time, the atlas-CT based MRAC was compared to the patient-specific-CT-based MRAC for brain PET imaging in an integrated TOF PET/MRI system. Overall, the MRAC-atlas achieves quantification accuracy similar to CTAC with a small but measurable difference of 5% in values, which is 2.6% higher than the error of the MRAC-patient.

Authors’ Affiliations

University of California, San Francisco, USA
GE Healthcare, USA


© Yang et al; licensee Springer. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.