Sometimes a buyout is a good news-bad news sort of situation for shareholders. While buyouts almost always come at a premium to the stock's recent price, investors are sometimes left feeling as though management sold the company out from underneath them for too low a price.

For owners who thought that medical imaging equipment maker CTI Molecular Imaging (NASDAQ:CTMI) had turned the corner, Friday's announcement that the company was selling itself to Siemens (NYSE:SI) for $20.50 in cash could be a mixed blessing.

On the positive side, a quick look back shows that things haven't always been so rosy for CTI. Shares could have been purchased for less than $8 back in late October, as Wall Street concerns about profit growth and competition from the likes of General Electric (NYSE:GE) weighed on the stock.

So, from the perspective of someone who purchased in the fall, a six-month return of 150% or more might seem like a pretty sweet deal. But, of course, there is another side to the story.

Results were up strongly in the most recent quarter and analysts were expecting some pretty robust EPS growth out into 2006. What's more, bulls on the stock noted that the company was getting reimbursement clearance for more and more indications -- suggesting that the overall picture for potential sales was brightening.

While the price offered by Siemens represents nearly a $3 premium to the price of CTI Molecular shares before the deal, the deal values CTI Molecular at only a little above two times trailing revenue. Admittedly, the deal looks quite reasonable on a P/E or free cash flow valuation basis, but medical device companies are often valued on a price-to-sales metric, and some investors may be thinking that management is selling too soon and for too little.

Whatever the case, this story is pretty much at an end. Given that the spread between the stock's current price ($20.38 at the time of this writing) and tender price ($20.50) is so small, there's not even much of an arbitrage opportunity left here. So, whether they like the deal or not, investors should begin looking for the next opportunity. Luckily, there are thousands more stocks to choose from.

Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long, nor short the shares).