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Document type:
Zeitschriftenaufsatz
Author(s):
Eiber, M.; Martinez-Möller, A.; Souvatzoglou, M.; Holzapfel, K.; Pickhard, A.; Loeffelbein, D.; Santi, I.; Rummeny, E.; Ziegler, S. I.; Schwaiger, M.; Nekolla, S.; Beer, A.
Title:
Value of a Dixon based MR/PET attenuation correction sequence for the localization and evaluation of PET positive lesions
Abstract:
Purpose: In this study, the potential contribution of Dixon-based MR imaging with a rapid low-resolution breath-hold sequence, which is a technique used for MR-based attenuation correction (AC) for MR/positron emission tomography (PET), was evaluated for anatomical correlation of PET-positive lesions on a 3T clinical scanner compared to low-dose CT. This technique is also used in a recently installed fully integrated whole-body MR/PET system. Methods: Thirty-five patients routinely scheduled for oncological staging underwent 18F-fluorodeoxyglucose (FDG) PET/CT and a 2-point Dixon 3-D volumetric interpolated breath-hold examination (VIBE) T1-weighted MR sequence on the same day. Two PET data sets reconstructed using attenuation maps from low-dose CT (PETAC_CT) or simulated MR-based segmentation (PETAC_MR) were evaluated for focal PET-positive lesions. The certainty for the correlation with anatomical structures was judged in the low-dose CT and Dixon-based MRI on a 4-point scale (0–3). In addition, the standardized uptake values (SUVs) for PETAC_CT and PETAC_MR were compared. Results: Statistically, no significant difference could be found concerning anatomical localization for all 81 PET-positive lesions in low-dose CT compared to Dixon-based MR (mean 2.51±0.85 and 2.37±0.87, respectively; p=0.1909). CT tended to be superior for small lymph nodes, bone metastases and pulmonary nodules, while Dixon-based MR proved advantageous for soft tissue pathologies like head/neck tumours and liver metastases. For the PETAC_CT- and PETAC_MR-based SUVs (mean 6.36±4.47 and 6.31±4.52, respectively) a nearly complete concordance with a highly significant correlation was found (r=0.9975, p<0.0001). Conclusion: Dixon-based MR imaging for MR AC allows for anatomical allocation of PET-positive lesions similar to low-dose CT in conventional PET/CT. Thus, this approach appears to be useful for future MR/PET for body regions not fully covered by diagnostic MRI due to potential time constraints.
Keywords:
MedicalImaging, CAMP,PET, PET/CT, PET/MR
Journal title:
European Journal of Nuclear Medicine and Molecular Imaging
Year:
2011
Journal volume:
38
Journal issue:
9
Pages contribution:
1691--1701
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