A New Method for

Poroelastography has been re cently in tro duced as a new elastographic tech nique that may be used to de scribe the spa tial and tem po ral be hav ior of poroelastic ma te ri als. The ex per i men tal meth od ol ogy pro posed thus far for phan toms and tis sues in vi tro re quires the ac qui si tion of a precompression rf frame, the ap pli ca tion of a unit step strain com pres sion to the sam ple and the ac qui si tion of sub se quent post compression frames from the ma te rial. Elastograms and poro elastograms are gen er ated by cross-cor re lat ing the se quen tially-ac quired post compression frames with the ref er ence precompression frame. The ap pli ca tion of poroelastography to tis sues in vivo must ad dress the echo decorrelation prob lems that are en coun tered due to un con trolled tis sue mo tion, which may be come sig nif i cant shortly af ter the ac qui si tion of the precompression frame. In this pa per, we in ves ti gate the fea si bil ity of per form ing poro elastography ex per i ments us ing an al ter na tive ex per i men tal scheme. In the pro posed ex per i men tal meth od ol ogy, the ref er ence precompression frame is con tin u ously moved while the time in ter val be tween the frames that are cor re lated is kept short. This al lows long data ac qui si tion times with si mul ta neous minimization of the decorrelation due to un de sired tis sue mo tion in vivo. We val i dated this new method us ing both a step and a ramp com pres sion func tions. We per formed poroelastographic sim u la tions and ex per i ments in phan toms and in tis sues in vivo. The re sults were com pared to those ob tained us ing the tra di tional ac qui si tion meth od ol ogy. This study shows that the two meth ods yield sim i lar re sults in vi tro and sug gests that the new method may be more ro bust to decorrelation noise in ap pli ca tions in vivo.