Abstract | PURPOSE: Multimodal molecular imaging allows a direct coregistration of different images, facilitating analysis of the spatial relation of various imaging parameters. Here, we further explored the relation of proliferation, as measured by [ 18F]FLT PET, and water diffusion, as an indicator of cellular density and cell death, as measured by diffusion-weighted (DW) MRI, in preclinical tumor models. We expected these parameters to be negatively related, as highly proliferative tissue should have a higher density of cells, hampering free water diffusion. PROCEDURES: Nude mice subcutaneously inoculated with either lung cancer cells (n = 11 A549 tumors, n = 20 H1975 tumors) or colorectal cancer cells (n = 13 Colo205 tumors) were imaged with [ 18F]FLT PET and DW-MRI using a multimodal bed, which was transferred from one instrument to the other within the same imaging session. Fiducial markers allowed coregistration of the images. An automatic post-processing was developed in MATLAB handling the spatial registration of DW-MRI (measured as apparent diffusion coefficient, ADC) and [ 18F]FLT image data and subsequent voxel-wise analysis of regions of interest (ROIs) in the tumor. RESULTS: Analyses were conducted on a total of 76 datasets, comprising a median of 2890 data points (ranging from 81 to 13,597). Scatterplots showing [ 18F]FLT vs. ADC values displayed various grades of relations (Pearson correlation coefficient (PCC) varied from - 0.58 to 0.49, median: -0.07). When relating PCC to tumor volume (median: 46 mm3, range: 3 mm3 to 584 mm3), lung tumors tended to have a more pronounced negative spatial relation of [ 18F]FLT and ADC with increasing tumor size. However, due to the low number of large tumors (> ~ 200 mm3), this conclusion has to be treated with caution. CONCLUSIONS: A spatial relation of water diffusion, as measured by DW-MRI, and cellular proliferation, as measured by [ 18F]FLT PET, cannot be detected in the experimental datasets investigated in this study.
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Authors | Sonja Schelhaas, Lynn Johann Frohwein, Lydia Wachsmuth, Sven Hermann, Cornelius Faber, Klaus P Schäfers, Andreas H Jacobs |
Journal | Molecular imaging and biology
(Mol Imaging Biol)
Vol. 24
Issue 3
Pg. 359-364
(06 2022)
ISSN: 1860-2002 [Electronic] United States |
PMID | 34755247
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | © 2021. The Author(s). |
Chemical References |
- Dideoxynucleosides
- Water
- Fluorodeoxyglucose F18
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Topics |
- Animals
- Dideoxynucleosides
- Diffusion Magnetic Resonance Imaging
(methods)
- Fluorodeoxyglucose F18
(metabolism)
- Heterografts
- Humans
- Lung Neoplasms
(diagnostic imaging)
- Magnetic Resonance Imaging
- Mice
- Mice, Nude
- Positron-Emission Tomography
(methods)
- Water
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