Abstract #1336

Olsson L, Hockings P

T2 relaxation of mouse lungs at end-expiration and end-inspiration was measured in vivo at 4.7 T (CPMG, interecho time 3.5 ms). T2 was longer (p<0.01) at end-expiration (9.70.7 ms) than at end-inspiration (9.00.8 ms). Relative proton density (lung/muscle tissue) was higher (p<0.001) during expiration (0.610.06), than inspiration (0.480.05). T2 increased linearly (p< 0.001, r2=0.49) with increasing proton density. To our knowledge, this is the first time the phenomenon is observed in vivo and for a normal breathing cycle.