Business keeps picking up at portable ultrasound equipment specialist SonoSite (NASDAQ:SONO). The company announced that revenue grew by approximately 20% during the December quarter.

Why would the company issue a top-line glimpse to investors when its actual fourth-quarter report won't be released until the middle of February? Well, the company's CEO is speaking at a health conference sponsored by JPMorgan (NYSE:JPM) tomorrow. By issuing the preliminary revenue report, Kevin Goodwin will now be free to discuss it to those in attendance.

The early report also allows us to confirm that revenue growth is in fact accelerating at SonoSite. After growing its top line by 13% through the first half of the year and by 16% in the third quarter, the final period's 20% uptick is refreshing.

The company isn't providing much in terms of color behind the spurt. If the previous quarter was any indicator, we're probably looking at healthier growth in hospital sales and in Europe, sandbagged by relatively weaker direct stateside sales. Either way, SonoSite is a Rule Breakers newsletter recommendation that is heading in the right direction.

Sure, it may not be as steamy as another medical device maker that has more than doubled since being singled out in the same newsletter -- da Vinci surgical robotic arm creator Intuitive Surgical (NASDAQ:ISRG) -- but SonoSite's gear is still selling briskly.

Back in October, the company had indicated that revenue would grow "at least" 15% to 18% higher in 2007. After the sloppy start to 2006, that may have seemed overly optimistic. Now, it seems as if the "at least" qualifier may come into play if SonoSite's growth continues to accelerate.

Yes, growth can be a pretty ominous thing to find in some of SonoSite's ultrasound readings. Financially speaking, though, it's just what the doctor ordered.

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Longtime Fool contributor Rick Munarriz has seen a few ultrasound sessions take place, but they have all been from the larger, old-school variety. He does not own shares in any of the companies mentioned in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.