Using a ''CSI: Crime Scene Investigation''-ish pace and visual approach, ''Medical Investigation'' gathers alumni of other series as the doctors, who are introduced in the pilot episode as they try to determine what felled an apparently healthy businessman (guest star Michael Nouri, ''Flashdance'') while he was in the midst of a cell-phone conversation on a busy street.

Neal McDonough (''Boomtown'') plays abrupt but dedicated team leader Stephen Connor,who is struggling to reach an accord with his estranged wife and keep a place in his young son's life despite his frequent calls to duty. Kelli Williams (''The Practice'') stars as his second-incommand, Dr. Natalie Durant, who constantly proves herself able to give as good as she gets from him. Christopher Gorham (the title star of last season's ''Jake 2.0''), Anna Belknap (of last year's ''The Handler'') and Troy Winbush (''Soul Food'') round out the regular cast.

After his acclaimed work as prosecutor David McNorris during the season-and-a-half of the ensemble drama ''Boomtown,'' McDonough is glad to have series work again. ''That was a phenomenal show, and I had a fantastic time doing it,'' he says. ''I'd go to work two days a week, but it's different being the lead of a show now. You go through 10 pages of dialogue in a day and do a scene 50 times. My hat goes off to guys like Dennis Franz ('NYPD Blue') who have done it for 10 years.''

McDonough also praises TV forerunners who have had to master medical jargon. ''We have to get the vernacular correct because we owe the truth to these situations, and we're trying to deliver that as much as we can within the realm of television.'' To that end, McDonough also researched his ''Medical Investigation'' role by shadowing Don Francis, the Centers for Disease Control researcher played by Matthew Modine in the AIDS-themed 1993 HBO movie ''And the Band Played On.''

''For me,'' McDonough says, ''the interesting part is not whether someone is a doctor or a lawyer, but the human struggle that person goes through, and Don Francis certainly has had that. I mean, you go off to work and subject yourself to disease and possible infection, then you have to go home and kiss your wife; she may not be very understanding for very long. Don is great at doing what he does, but I'm sure there are times he'd rather be a car salesman. That's just not his gift, and it's the same thing with Stephen Connor. He knows how to save millions of people's lives, but he can't figure out how to save his marriage ... or himself.''

Williams is hoping to get as detailed a personal story for her new alter ego, having had such a big one on ''The Practice'' as lawyer Lindsay. However, some of her relatives would be content just to watch her play doctor. ''My father and my mother-in-law are both doctors,'' Williams reports, ''so I have a lot of people I can call and ask questions of. In every episode, there's one part where we rattle off all these complicated terms; at this point, I haven't a clue what I'm saying, but I'll hopefully get the hang of it little by little.''

While ''Medical Investigation'' plots might seem to stem from writers' imaginations, Williams maintains, ''It's all based on medical possibility. These things could happen, and some are taken from true events. The situation in the pilot actually occurred in the 1950s.''

Despite that, Williams anticipates ''CSI'' comparisons due to her new show's style. ''People like to put things in categories,'' she reasons. ''Procedural shows are very popular, and there are some similarities, but we're dealing with diseases instead of people ­­as the 'criminals'.''

McDonough adds, ''There's a massive difference between our show and 'CSI.' Their show is about solving heinous crimes involving people who are murdered or raped; our show is about finding and stopping little microbes that are infecting and killing people. At the end of each episode, in the face of despair is hope. These characters are saving lives, not trying to figure out who killed who.''

Still, one decidedly ''CSI''-ish element of ''Medical Investigation'' projects Connor back to the moment when the given disease struck, with those directly affected appearing to him as ghostlike visions. Those scenes are filmed on what, McDonough muses, have become known on the show's set as ''Tech Thursdays.''

He explains, ''The whole day is spent just on that visualization, and it's a lot of work to make it look as great as it does. It's far beyond my realm of understanding, but the result is truly remarkable.''