Sergios Gatidis MD, Abstract Co-Author: Nothing to Disclose

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

Brigitte Gueckel, Abstract Co-Author: Nothing to Disclose

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

Christian la Fougere, Abstract Co-Author: Nothing to Disclose

Konstantin Nikolaou MD, Abstract Co-Author: Speakers Bureau, Siemens AG Speakers Bureau, Bracco Group Speakers Bureau, Bayer AG

Nina Schwenzer MD, Abstract Co-Author: Nothing to Disclose

Juergen F. Schaefer MD, Presenter: Nothing to Disclose

To evaluate the technical feasibility and clinical performance of combined whole-body PET/MRI in comparison to 18F-FDG-PET/CT in infants and young children with solid tumors.

This prospective study was approved by the local ethics committee. 10 examinations were performed in 9 children (3 female, age 4.4±1.8 years) with solid tumors. After i.v.-administration of 81±30 MBq 18F-FDG all patients were first examined by means of contrast-enhanced PET/CT (Biograph mCT, Siemens, 62±4 min uptake) and subsequently via non-enhanced PET/MRI (Biograph mMR, Siemens, 115±13 min uptake). The PET/MRI protocol included a Dixon sequence for PET attenuation correction as well as coronal STIR, axial T2w, axial T1w sequences and DWI. SUVs of PET(CT) and PET(MRI) were measured in healthy tissues and tumor lesions. Lesion conspicuity was compared qualitatively between CT and MRI. Effective doses were estimated separately for PET and CT.

All examinations were completed offering good diagnostic image quality. PET of PET/CT and PET/MRI showed complete agreement in the detection of focal FDG-uptake. SUVs of PET(CT) and PET(MR) correlated well with correlation coefficients above 0.7. Relevant additional information was obtained by MRI compared to CT in 5 cases (local staging of soft-tissue lesions in 2 cases, morphological PET-correlation in 3 cases). Theoretical dose reduction in PET/MRI compared to PET/CT was 47±12 %.

PET/MRI is a promising modality for the examination of young children with solid tumors showing equivalent qualitative and quantitative results compared to PET/CT. Advantages of PET/MRI lie in the evaluation of soft tissue lesions. Importantly for this patient population, effective dose of PET/MRI is significantly lower than in PET/CT.

The results of this study encourage the use of FDG-PET/MRI as an equivalent alternative to FDG-PET/CT with significantly lower radiation exposure. When available, PET/MRI should be considered as the primary imaging tool for tumor staging of young children and infants with solid malignancies.

Gatidis, S, Schmidt, H, Gueckel, B, Pfannenberg, C, la Fougere, C, Nikolaou, K, Schwenzer, N, Schaefer, J, Simultaneous Whole-body PET/MRI in Comparison to PET/CT in Pediatric Oncology: Initial Results in Infants and Young Children.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045760.html