BOTHELL — SonoSite Inc. won a partial victory Thursday in its legal tussle with GE Healthcare over portable ultrasound technology.

A federal judge in Madison, Wis., granted summary judgment motions in SonoSite’s favor on five of the six patents that GE had asserted. The judge ruled one of GE’s patents was invalid and that SonoSite’s technology does not infringe on four other GE patents.

The court also granted summary judgment motions in GE’s favor on two of the patents that Bothell-based SonoSite is trying to assert in its countersuit against GE.

Kevin Goodwin, SonoSite’s chief executive officer, said the rulings put SonoSite ahead as the two sides prepare for a trial on the remaining patents.

“Of the six patents GE claimed against us, one is still remaining, and of the four we asserted against GE, two are still standing,” Goodwin said. “This is great news, and we look forward to a trial in August.”

SonoSite and GE, which compete head-to-head in the medical industry with several models of hand-carried ultrasound machines, have waged a legal battle against each other since May 2007.

GE fired the first shot, alleging that ultrasound technology made by SonoSite infringes on five GE patents. GE filed the federal district court lawsuit in Madison, Wis., where the GE Healthcare division is located.

Thursday’s judgments came just days after SonoSite announced a settlement in a similar patent fight with Zonare Medical Systems, another rival maker of portable ultrasound equipment.

The legal skirmishes are costing SonoSite. The company said legal expenses reached $3.5 million during the second quarter of this year.

That figure was revealed during SonoSite’s release of its second-quarter financial results, which included $59 million in revenue, up 25 percent from a year ago. The company’s profit grew 48 percent to $2.5 million, or 14 cents a share, compared with $1.7 million in the year-ago period. Goodwin said SonoSite’s newest product lines, released last year, accounted of more than half of the company’s sales.

Reporter Eric Fetters: 425-339-3453 or fetters@heraldnet.com.