When you saw them at $3+ they had several drug candidates going on. They canceled some to focus on Imagify, an imaging agent to reduce nuclear stress testing costs and exposure to radition. Funding was running short this year, though they have been negotiating since Nov 07 with major Parma's for a funding/royalty deal. Just after the share hit .32 they liscenced a technology for 10 mill and the shares recovered, but management is worried about staying on the nasdaq listing. (10 consecutive days over $1 ashare by june I think.
Imagify will be a huge product, ACUS has a validated manufacturing facility just for it and the drug application was submitted late april. They may issue more shares since they have 98 mill right now only.