MRI-Guided Derivation of the Input Function for PET Kinetic Modeling.

Blood samples obtained by arterial cannulation are the gold standard to measure the input function for PET pharmacokinetic modeling. There is interest in less invasive methods, such as image-derived input functions (IDAIF). MRI can be used to segment and correct partial volume effects of the PET images, improving IDAIF extraction. Preclinical studies have shown that the input function of PET tracers, namely fluorodeoxyglucose and [(18)F]fluoroethyl-l-tyrosine, can be derived from the Gd-DTPA input function. Noninvasive, MRI-guided, PET input function derivation is a promising avenue to reduce or eliminate the need for arterial plasma samples in preclinical and clinical settings.