Combining MRI With PET for Partial Volume Correction Improves Image-Derived Input Functions in Mice
Transactions on Nuclear Science
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Evans, E., Buonincontri, G., Izquierdo, D., Methner, C., Hawkes, R., Ansorge, R., Krieg, T., et al. (2015). Combining MRI With PET for Partial Volume Correction Improves Image-Derived Input Functions in Mice. Transactions on Nuclear Science, 62 628-633. https://doi.org/10.1109/TNS.2015.2433897
Accurate kinetic modelling using dynamic PET requires knowledge of the tracer concentration in plasma, known as the arterial input function (AIF). AIFs are usually determined by invasive blood sampling, but this is prohibitive in murine studies due to low total blood volumes. As a result of the low spatial resolution of PET, image-derived input functions (IDIFs) must be extracted from left ventricular blood pool (LVBP) ROIs of the mouse heart. This is challenging because of partial volume and spillover effects between the LVBP and myocardium, contaminating IDIFs with tissue signal. We have applied the geometric transfer matrix (GTM) method of partial volume correction (PVC) to 12 mice injected with ^18F - FDG affected by a Myocardial Infarction (MI), of which 6 were treated with a drug which reduced infarction size . We utilised high resolution MRI to assist in segmenting mouse hearts into 5 classes: LVBP, infarcted myocardium, healthy myocardium, lungs/body and background. The signal contribution from these 5 classes was convolved with the point spread function (PSF) of the Cambridge split magnet PET scanner and a non-linear fit was performed on the 5 measured signal components. The corrected IDIF was taken as the fitted LVBP component. It was found that the GTM PVC method could recover an IDIF with less contamination from spillover than an IDIF extracted from PET data alone. More realistic values of K_i were achieved using GTM IDIFs, which were shown to be significantly different (p < 0.05 ) between the treated and untreated groups.
arterial input function, geometric transfer matrix, MRI, partial volume correction, small animal PET
E. Evans was funded by an MRC studentship and travel to PSMR 2014 was funded by the EU COST action for PET/MR.
MEDICAL RESEARCH COUNCIL (G0001354)
External DOI: https://doi.org/10.1109/TNS.2015.2433897
This record's URL: https://www.repository.cam.ac.uk/handle/1810/248844