As promised, the drugmaker is moving ahead with plans to shrink and re-focus by agreeing to sell the unit to Avista Capital Partners, a private equity firm, for cash. The business, by the way, makes and sells medical imaging products used during ultrasound and diagnostic procedures. During a briefing for Wall Street earlier this month, Bristol ceo Jim Cornelius indicated the unit was up for sale.

“As Bristol-Myers Squibb continues to focus on evolving into a next-generation biopharma company, we determined the best way to maximize the value of medical imaging for shareholders was to sell this business and reinvest the proceeds into our pharmaceutical research, development and commercialization efforts,” Cornelius says in a statement.

The medical imaging unit’s biggest product, called Cardiolite, had sales of $408 million in 2006, but the product faces increased generic competition after a key patent expires in 2008, the Associated Press points out.

The drugmaker is in the process of laying off about 4,300 employees, or 10 percent of its staff, and closing more than half of its manufacturing plants to save $1.5 billion by 2010 (see more details here). The ConvaTec wound-care supplies unit ConvaTec and Mead Johnson Nutritionals business may also be up for grabs.