Nina F Schwenzer MD, Presenter: Nothing to Disclose

Lars Stegger MD,PHD, Abstract Co-Author: Nothing to Disclose

Andreas Boss MD, Abstract Co-Author: Nothing to Disclose

Matthias Klaus Werner MD, Abstract Co-Author: Nothing to Disclose

Christina Schraml MD, Abstract Co-Author: Nothing to Disclose

Armin Kolb, Abstract Co-Author: Nothing to Disclose

Sotirios Bisdas MD, Abstract Co-Author: Nothing to Disclose

Mark Mueller MD, Abstract Co-Author: Nothing to Disclose

Matthias Reimold MD, Abstract Co-Author: Nothing to Disclose

Christina Pfannenberg MD, Abstract Co-Author: Nothing to Disclose

Claus Detlef Claussen MD, Abstract Co-Author: Nothing to Disclose

Holger Schmidt PhD, Abstract Co-Author: Nothing to Disclose

Current state of image quality in a new dedicated hybrid BrainPET/MRI system.

50 patients with intracranial masses, head and upper neck tumors or neurodegenerative diseases were examined with a hybrid BrainPET/MRI consisting of a conventional 3T scanner and an MR-compatible PET insert. PET images of the PET/MR were attenuation corrected with MR images. Directly before PET/MRI all patients underwent a routine PET/CT exam with either [18F]FDG, [11C]methionine or [68Ga]DOTATOC according to standard protocols. In addition to anatomical MRI, functional imaging was performed including diffusion tensor imaging (DTI) and arterial spin labelling. Overall diagnostic MRI quality was visually evaluated by two radiologists. PET data quality was assessed by using tumor delineation and FDG uptake as criteria; tumor delineation with [11C]methionine and [68Ga]DOTATOC was rated on a 4-point-scale, FDG uptake quantification accuracy was evaluated in 10 corresponding PET/MR and PET/CT datasets by means of ROI analysis (right and left frontal and temporo-occipital lobes at the level of the basal ganglia). In addition, the asymmetry indices were calculated.

In 45 out of 50 patients, the PET/MRI examinations were conducted as planned and both PET and MRI data were successfully recorded. In 5 patients, the PET/MRI examination could not be performed due to claustrophobia, transportation or scanner-related problems. Visual analysis revealed diagnostic image quality of anatomical MRI. Functional MRI was possible in all but one patient (non-diagnostic DTI due to dental prothesis). Comparable tumor delineation was found in the PET datasets when using PET/MR and PET/CT with [11C]methionine; additional lesions were found in 2 out of 7 [68Ga]DOTATOC datasets when using the PET/MRI. For FDG mean asymmetry index revealed a high accordance between the PET of the PET/CT and the PET/MRI: mean asymmetry index was 0.7±1.8% vs 1.2±1.9%, respectively.

The hybrid BrainPET/MRI allows for molecular, anatomical and functional imaging with uncompromised MR image quality and a high accordance of PET results between PET/MRI and PET/CT for the evaluated radiotracers.

The hybrid BrainPET/MRI allows for simultaneous molecular, anatomical and functional imaging. It may essentially contribute to the transfer of this technique into whole-body PET/MR systems.

Schwenzer, N, Stegger, L, Boss, A, Werner, M, Schraml, C, Kolb, A, Bisdas, S, Mueller, M, Reimold, M, Pfannenberg, C, Claussen, C, Schmidt, H, Hybrid PET/MRI in a Dedicated Human Brain System: Current Results.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11006918.html