Milica Medved1, Aytekin Oto1, Xiaobing Fan1, Federico D. Pineda1, Russell Z. Szmulewitz2, Gregory S. Karczmar1
1Radiology, University of Chicago, Chicago, IL, United States; 2Medicine, University of Chicago, Chicago, IL, United States
In applications of the two compartment model to tissue contrast agent uptake and washout, it is critical to determine the arterial input function (AIF). The AIF cannot always be measured directly, and approximate methods are sometimes used to derive it. For example, it can be derived by using muscle with known Ktrans and ve values as a reference tissue. Published values for skeletal muscle are used, typically measured in an accessible muscle, such as the calf. We show that Ktrans and ve vary between gluteal and deep pelvic muscles, and that thus skeletal muscles should be characterized individually.