Fig. 1.

Soft-tissue attenuation correction (AC) of ¹⁸F-FDG PET images based on MRI. (A) Uncorrected thoracic PET scan showing relative activity enhancement in the lungs and along the outer contours of the patient. (B and C) 3D Dixon volume interpolated breath-hold examination (VIBE) MR sequence providing separate water/fat “in-phase” and “opposed-phase” images that serve as basis for soft-tissue segmentation. (D) Segmented soft tissue groups (air, fat, muscle, lungs) that can be assigned to a 3D PET attenuation map. (E) Resulting attenuation corrected PET scan of the initial data set (A). Note: Bone signal is assigned soft tissue values in this MRI-based approach for AC