MOUNTAIN VIEW, Calif. (AP) ¿ Hansen Medical Inc., which makes medical robotic technology used with catheters, said Thursday it expects its first-quarter revenue to fall under Wall Street's expectations. The company expects first-quarter revenue to be in the range of $7 million to $7.2 million. Analysts surveyed by Thomson Reuters, on average, predict sales of $7.8 million. Hansen said it expects to sell less of its Sensei robotic catheter systems that it originally expected. It now predicts it will sell 53 to 60 this year, compared with a previous expectation of 53 to 65. The company also said it plans to sell an undisclosed amount of its shares in a public offering. Piper Jaffray & Co. will be the sole underwriter for the sale. Shares rose 15 cents, or 4.1 percent, to close Thursday at $3.82.