The Hidden Challenge: Unraveling the Reliability of Pelvic Attenuation Maps in Simultaneous PET/MRI

Motivation: PET/MRI integrate functional and anatomical information, elevating diagnostic precision. However, a key challenge lies in ensuring the reliability of attenuation (µ) map generation. Goal(s): This research assesses the accuracy of PET/MR-based µ-map from 3D-Dixon and 3D-Dixon Hires T1W in comparison to a standard µ-map from PET/CT at the voxel level. Approach: the µ-map data from 15 patients who underwent both PET/CT and PET/MRI of the pelvic region were analyzed to quantify the disparities in the generated µ-maps. Results: We found that 3D-Dixon Hires outperforms the 3D-Dixon in the creation of µ-maps, rendering it a superior choice for precise attenuation correction. Impact: Spatial resolution influences the accuracy of attenuation correction in PET/MRI, particularly when employing quantitative methods for diagnosis. Notably, the utilization of higher-resolution Dixon MRI images enhances the reliability of attenuation in tissue compartmental models for the generation of this map.