Anomalous iron-induced CPMG relaxation: importance of particle size
Ghugre N, Wood J, Enriquez C
Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California
MRI based non-invasive detection of tissue iron overload is becoming a clinically important tool. Compared to single-echo, CPMG techniques are faster and may offer greater insight into the effective size of iron clusters as well as residence/exchange times of proton pools. However, they exhibit complicated non-monoexponential signal decay and anomalous T2 behavior with echo-spacing(&[tau]) in human liver. In order to investigate, we studied T2-&[tau] behavior for three paramagnetic particles of different radii: ferritin (~7 nm), Feridex (~30 nm) and synthetic liposomes (400 nm). Our relaxometry observations suggest that iron particles must have a critical physical size to produce in-vivo behavior.