Purpose: To assess the patient-dependent accuracy of atlas-based attenuation correction (ATAC) for brain positron emission tomography (PET) in an integrated time-of-flight (TOF) PET/magnetic resonance (MR) imaging system. Materials and Methods: Thirty recruited patients provided informed consent in this institutional review board-approved study. All patients underwent whole-body fluorodeoxyglucose PET/computed tomography (CT) followed by TOF PET/MR imaging. With use of TOF PET data, PET images were reconstructed with four different attenuation correction (AC) methods: PET with patient CT-based AC (CTAC), PET with ATAC (air and bone from an atlas), PET with ATACpatientBone (air and tissue from the atlas with patient bone), and PET with ATACboneless (air and tissue from the atlas without bone). For quantitative evaluation, PET mean activity concentration values were measured in 14 1-mL volumes of interest (VOIs) distributed throughout the brain and statistical significance was tested with a paired t test. Results: The mean overall difference (6standard deviation) of PET with ATAC compared with PET with CTAC was 20.69 kBq/mL ± 0.60 (24.0% ± 3.2) (P < .001). The results were patient dependent (range, 29.3% to 0.57%) and VOI dependent (range, 25.9 to 22.2). In addition, when bone was not included for AC, the overall difference of PET with ATACboneless (29.4% ± 3.7) was significantly worse than that of PET with ATAC (24.0% ± 3.2) (P < .001). Finally, when patient bone was used for AC instead of atlas bone, the overall difference of PET with ATACpatient-Bone (21.5% ± 1.5) improved over that of PET with ATAC (24.0% ± 3.2) (P < .001). Conclusion: ATAC in PET/MR imaging achieves similar quantification accuracy to that from CTAC by means of atlas-based bone compensation. However, patient-specific anatomic differences from the atlas caused bone attenuation differences and misclassified sinuses, which result in patient-dependent performance variation of ATAC.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging