Fujifilm of Tokyo will pay about $753 million in cash and assume $242 million in debt. The payment of $54 in cash per SonoSite share represents a 75.4% premium to SonoSite's Nov. 2 close, the day before news outlets reported that SonoSite had hired advisers to explore a sale. It's also a 28% bonus to the stock's Wednesday close.

"SonoSite's products are designed for applications where ultrasound has not typically been used, such as emergency medicine, surgery, critical care, internal medicine, musculoskeletal, and vascular access procedures," the company said.

Fujifilm has used occasional acquisitions to boost its medical equipment operations as it continues to adjust to the conversion to digital photography and waning interest in its traditional film activities. In 2008 it bought Toyama Chemical Co. Ltd. for about $1.5 billion to add drugs to its portfolio and earlier this year bought the contract biopharmaceutical manufacturing division of Merck & Co.

Although financial investors dropped out of the auction early, Fujifilm beat out domestic rival Samsung Electronics Co. Ltd., which this year bought a majority stake in South Korean ultrasound equipment maker Medison Co. Ltd. for a reported $262 million.

The boards of both Fujifilm and SonoSite have approved the transaction and Fujifilm said it needs shareholders representing a simple majority of SonoSite shares to accept the agreement for it to move forward.

SonoSite's revenue for the first nine months of the year was $219.5 million, an increase of 18% over the previous year's period, but operating profit fell 29% to $9.9 million. The company took a $1.3 million charge on layoffs to cut costs.

SonoSite's management team will remain in place once it becomes a unit of Fujifilm, the company said.

Fujifilm had been interested in the target for several years but first launched talks in 2010, Koichi Tamai, head of Fujifilm's medical systems, told reporters. He said SonoSite has 37% of the portable ultrasound market and that his company wants to surpass General Electric Co. as the No. 1 maker.

The announcement was made after trading closed in Tokyo. Fujifilm slipped 2.2% to ¥1,841 ($23.67).

Barclays Capital is providing financial advice to the buyer, which is receiving legal counsel from Shearman & Sterling LLP. J.P. Morgan Securities LLC and GCA Savvian Advisors LLC are advising SonoSite, while Fenwick & West LLP is providing legal assistance.