Impact of hybrid PET/MR technology on multiparametric imaging and treatment response assessment of cervix cancer

• Published in: Radiotherapy and oncology Vol. 125; no. 3; pp. 420 - 425
• Main Authors: Daniel, Michaela, Andrzejewski, Piotr, Sturdza, Alina, Majercakova, Katarina, Baltzer, Pascal, Pinker, Katja, Wadsak, Wolfgang, Mitterhauser, Markus, Pötter, Richard, Georg, Petra, Helbich, Thomas, Georg, Dietmar
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01-12-2017
• Subjects: [18F]FMISO; Adult; Aged; Cervix cancer; Female; Humans; Hypoxia; Magnetic Resonance Imaging - methods; Middle Aged; Misonidazole - analogs & derivatives; Multimodal Imaging - methods; Multiparametric; PET/MRI; Positron-Emission Tomography - methods; Radiopharmaceuticals; Treatment assessment; Uterine Cervical Neoplasms - diagnostic imaging; Hypoxia; Cervix cancer; PET/MRI; Treatment assessment; [18F]FMISO; Multiparametric; [F]FMISO
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2017.10.036

Multimodal tissue characterization by combined MRI and PET has high clinical potential in the context of sub-target definition for dose painting and response assessment but its clinical exploration is yet limited. The aim of this study was to prove the potential and feasibility of hybrid PET/MRI to non-invasively measure tumor hypoxia, perfusion and microstructure at one stop in tumors of the uterine cervix during chemoradiotherapy.
Ten cervix cancer patients were subjected to simultaneous multiparametric PET/MRI with [18F]fluoromisonidazole ([18F]FMISO). Imaging was scheduled before, twice during and after chemoradiotherapy. Intra- and inter-time point analyses of the extracted parameters (i.e. ADC, Ktrans, ABrix, [18F]FMISO-tumor to background ratio (TBR)) were performed. The [18F]FMISO uptake- and ADC-spatio-temporal changes were assessed.
Patient averaged ADC values increased from baseline to follow up (1.03 ± 0.11/1.30 ± 0.13 × 10−3 mm2/s), while the TBR decreased (1.73 ± 0.24/1.36 ± 0.19), Ktrans dropped over time (0.17 ± 0.05/0.05 ± 0.05 min−1); for all above p < 0.05. None of these parameters correlated significantly on a voxel-by-voxel basis. Low-ADC regions spatially varied over time. There was pronounced reduction of the [18F]FMISO-avid volumes during treatment.
The suggested hybrid PET/MRI protocol to non-invasively investigate tumor hypoxia, perfusion and microstructure at one stop was feasible, revealing spatio-temporal response patterns that could be utilized for comprehensive sub-target definition for dose painting and response assessment.