Conspicuity of FDG-Avid Osseous Lesions on PET/MRI Versus PET/CT: a Quantitative and Visual Analysis.BACKGROUND
 Because standard MRI-based attenuation correction (AC) does not account for the attenuation of photons by cortical bone, PET/MRI may have reduced sensitivity for FDG-avid focal bone lesions (FFBLs).  This study evaluates whether MRI-based AC compromises detection of FFBLs, by comparing their conspicuity both quantitatively and qualitatively on PET/MRI versus PET/CT.


 One hundred ninety general oncology patients underwent whole-body PET/CT followed by whole-body PET/MRI, utilizing the same FDG dose.  SUV-mean was lower on PET/MRI for both FFBLs (-6.5 %, p = 0.009) and BB (-20.5 %, p < 0.001).  SUV-max was lower on PET/MRI for BB (-14.2 %, p = 0.002) but not for FFBLs (-6.2 %, p = 0.068).  The ratio of FFBL SUV-mean to BB SUV-mean was higher for PET/MRI (+29.5 %, p < 0.001).  Forty of 50 lesions (80 %) were visually deemed to be of equal or greater conspicuity on PET images derived from PET/MRI.  The mean interval from tracer administration to imaging was longer (p < 0.001) for PET/MRI (127 v. 62 min).


 Both FFBLs and BB had lower mean SUVs on PET/MRI than PET/CT.  Despite this systematic bias, FFBLs had greater conspicuity on PET/MRI, both qualitatively and quantitatively.  This difference was likely due to the longer tracer uptake times for PET/MRI, which allowed for more tracer accumulation by FFBLs and more tracer washout from BB.  Our results suggest that whole-body PET/MRI and PET/CT provide comparable sensitivity for detection of FDG-avid focal bone lesions.
PET/MRI
Conspicuity of FDG-Avid Osseous Lesions on PET/MRI Versus PET/CT: a Quantitative and Visual Analysis.BACKGROUND
 This study evaluates whether MRI-based AC compromises detection of FFBLs, by comparing their conspicuity both quantitatively and qualitatively on PET/MRI versus PET/CT.


 One hundred ninety general oncology patients underwent whole-body PET/CT followed by whole-body PET/MRI, utilizing the same FDG dose.  Both FFBLs and BB had lower mean SUVs on PET/MRI than PET/CT.  Our results suggest that whole-body PET/MRI and PET/CT provide comparable sensitivity for detection of FDG-avid focal bone lesions.
PET/CT