title: Quantitative correlation at the molecular level of tumor response to docetaxel by multimodal diffusion-weighted magnetic resonance imaging and [¹⁸F]FDG/[¹⁸F]FLT positron emission tomography.
abstract: We aimed to quantitatively characterize the treatment effects of docetaxel in the HCT116 xenograft mouse model, applying diffusion-weighted magnetic resonance imaging (MRI) and positron emission tomography (PET) using 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) and 3'-deoxy-3'-[¹⁸F]-fluorothymidine ([¹⁸F]FLT). Mice were imaged at four time points over 8 days. Docetaxel (15 mg/kg) was administered after a baseline scan. Voxel-wise scatterplots of PET and apparent diffusion coefficient (ADC) data of tumor volumes were evaluated with a threshold cluster analysis and compared to histology (GLUT1, GLUT3, Ki67, activated caspase 3a). Compared to the extensive tumor growth observed in the vehicle-treated group (from 0.32 ± 0.21 cm³ to 0.69 ± 0.40 cm³), the administration of docetaxel led to tumor growth stasis (from 0.32 ± 0.20 cm³ to 0.45 ± 0.23 cm³). The [¹⁸F]FDG/ADC cluster analysis and the evaluation of peak histogram values revealed a significant treatment effect matching histology as opposed to [¹⁸F]FLT/ADC. [¹⁸F]FLT uptake and the Ki67 index were not in good agreement. Our voxel-based cluster analysis uncovered treatment effects not seen in the separate inspection of PET and MRI data and may be used as an independent analysis tool. [¹⁸F]FLT/ADC cluster analysis could still point out the treatment effect; however, [¹⁸F]FDG/ADC reflected the histology findings in higher agreement.
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Honndorf
authors.forename: Holger
authors.initials: H
authors.lastname: Schmidt
authors.forename: Hans F
authors.initials: HF
authors.lastname: Wehrl
authors.forename: Stefan
authors.initials: S
authors.lastname: Wiehr
authors.forename: Walter
authors.initials: W
authors.lastname: Ehrlichmann
authors.forename: Leticia
authors.initials: L
authors.lastname: Quintanilla-Martinez
authors.forename: Hervé
authors.initials: H
authors.lastname: Barjat
authors.forename: Sally-Ann
authors.initials: SA
authors.lastname: Ricketts
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Pichler
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D015224:Dideoxynucleosides; D038524:Diffusion Magnetic Resonance Imaging; D000077143:Docetaxel; D005260:Female; D019788:Fluorodeoxyglucose F18; D045325:HCT116 Cells; D006801:Humans; D051379:Mice; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D043823:Taxoids / Q000008:administration & dosage*; D016896:Treatment Outcome; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D015224:Dideoxynucleosides; D019275:Radiopharmaceuticals; D043823:Taxoids; D019788:Fluorodeoxyglucose F18; D000077143:Docetaxel