(FORTUNE Magazine) - A bowl of broth--that was lunch the day I arrived in Richmond. For dinner, two bottles of lemon-flavored Fleet Phospho-soda and four bisacodyl tablets. You see where this is heading? I went to bed on an emptying stomach, slept fitfully, and woke feeling weak and lightheaded. By 7:30 A.M. I was in a hospital johnny, supine, my chest festooned with electrodes, my lower alimentary canal inflated like a balloon, as a gurney fed me headfirst into a $2 million GE-Imatron electron-beam tomography (EBT) scanner. Miserable and scared, in other words, and that was before I saw my test results.

PartnerMD, the party responsible for my suffering, is one of those new concierge medical clinics that cater to patients who are sick of HMOs and can afford better. For a $1,700 annual fee plus the cost of care ("not a whole lot more expensive than premium cable," says PartnerMD CEO Linda Nash, not quite persuasively), you get appointments that begin as scheduled, ample face time with a doctor, and a holistic approach to medicine that emphasizes screening and prevention over disease management-- and even house calls "when medically necessary." If the concept appeals but you can't find a clinic in your town, then for about $4,000, depending on which tests you choose, you can have a PartnerMD executive physical, as I did, and at least get a taste of the concierge treatment.

Following my EBT scan, I pulled up my pants and staggered down the hallway to get my blood work done, after which, mercifully, nurse Amy showed me to my private office--outfitted with a swivel chair, Internet access, and a radio pretuned to Lite 98 FM--where I feasted on nutty snacks and checked my e-mail. The actual physical exam, performed by Amy and my doctor for the day, Jim Mumper, lasted a full hour. That kind of schedule works only because each PartnerMD physician has no more than 600 patients, compared with 3,000 or so for the average GP.

Dr. Mumper joined me at noon to dine on roast pork and spinach salad while we discussed what brings executives to the doctor's office. "It's what you would expect," Mumper says. "Insomnia, sleep disturbances, chronic abdominal pain from irritable bowel syndrome, headaches, fatigue. The body doesn't like stress."

The afternoon passed in a whirlwind of subappointments: an hour of strength and fitness testing with Rose (64 overall on a scale of 100; it seems I'm not very flexible); a stress-management consultation with Sherry (among the findings: "Mr. Whitford has lots of things to do, and he cannot change that."); nutrition counseling with Valerie; and the highlight of my day, a one-hour massage with Melissa. "You can turn over now, David," Melissa whispered in my ear at the halfway point. I was naked under a towel. The lights were dim. Soothing New Age music tinkled softly from the CD player in the corner. "Whatever you say, Melissa," I mumbled drowsily.

All in all, a wonderful day--except for the EBT scan and the story it told. EBTs are cutting-edge diagnostic tools that can detect tumors anywhere in the body and uncover hidden evidence of heart disease. The tests run about $400 and are usually not covered by insurance. According to Mumper, that's because too often EBTs reveal false positives, in which case you have to return for a follow-up scan. On the other hand, nearly everyone agrees that EBTs are very good at detecting coronary plaque, or atherosclerosis--especially in patients who seem perfectly fine.

I walk five miles every day, I'm not overweight, I haven't smoked cigarettes since college, and there are no scary diseases in my family history. Nevertheless, my EBT scan revealed a calcium score in my left anterior descending coronary artery-- the one that's nicknamed the "widow maker," because if it clogs, you can die--of 121.54. That would be a decent number for a 75-year-old (the range runs from zero to the low thousands), but I'm only 49. Eighty-five percent of men my age have a lower score. "It's good that we know," was Dr. Mumper's sober comment as he looked over my results. "That alone makes your trip down here worthwhile."

When I followed up back home with a stress test, doctors found no evidence of diminished circulation. I wish I could feel good about that. Unfortunately, the whole point of the calcium score is to measure the extent to which plaque has invaded the arterial wall before it causes tearing or blockage.

A widely cited study published in the journal Radiology in 2003 found a high correlation between "the extent of coronary calcium"--that's the calcium score--and "mortality risk." My number means that while my overall risk profile remains low, I'm four times more likely to drop dead within five years than someone with a calcium score under ten.

What am I to do with such knowledge? I immediately asked my brother-in-law Ron for his advice. "It's bullshit!" he said. That's typical of Ron, a heart doctor who eats and drinks what he pleases, knowing, he says, that disease relates principally to one's genes. (When pressed, Ron said I could drink more; drunks often have exceptionally clean arteries.)

Mumper was more sanguine. "We're going to come up with a drug in your lifetime that's going to make plaque go away," he promised. Until then, the best anyone can do is address other, more responsive cardiac-risk factors through diet, exercise, and medication. Long story short, I switched to oatmeal for breakfast; replaced red meat, white bread, and dairy with fish, whole wheat, and soy; swore off snacking at work; started swallowing multivitamins, fish-oil pills, and a daily low-dose aspirin; took up swimming twice a week at the Y; and stopped worrying about how much wine I was drinking.

As if by magic, I lost 15 pounds in three weeks. Two months later, I repeated the blood work. My LDL (bad cholesterol), formerly 176, was now 116; my HDL (good cholesterol) had risen from 66 to 80; and my total cholesterol had dropped from 266 to 211. That was still a tad high, given my risk profile, so my home doctor put me on statins, and when I followed up four months later my LDL was 54; HDL, 82; and total cholesterol, 145. "These readings are great," my doctor gushed.

Thanks to my fancy physical, I'm now aware of certain imperfections in my aging physical plant: probable calcification on the right lobe of my prostate gland; a heart murmur; atypical nevi (moles); tinea versicolor (skin fungus); and the two biggies, hyperlipidemia (high cholesterol) and atherosclerotic coronary artery disease. Knowing all that, I've taken reasonable steps to improve my odds. "Don't worry," says the other doctor in my family, Ron's daughter Henya. "Your blood pressure is fine, your good cholesterol is high, you'll be fine. And one day you'll probably die of heart disease, like most of us will." I guess I can live with that.

This story was adapted from an article in the June issue of Fortune Small Business.

PartnerMD

Offers a battery of personalized tests at locations around the country. From $1,700; www.partnermd.com

Canyon Ranch

The health resort in Tuscon and Lenox, Mass., offers a four-day package including consultations with doctors from the Cleveland Clinic. From $6,680; canyonranch.com

Executive Medicine of Southlake

This new clinic near the Dallas--Fort Worth airport gives you 24/7 access to your doctor for a year after you visit. From $750 to $3,850; emsouthlake.com

Princeton Longevity Center

Not affiliated with the university, PLC in Princeton, N.J., offers tests like a 3-D virtual colonoscopy. From $3,250 to $4,150; theplc.net

As doctors become more adept at predicting heart attacks, they're paying increasing attention to calcium, whose presence can signal trouble long before a patient feels sick. Atherosclerosis, the most common form of heart disease, occurs when plaque accumulates in the walls of the coronary arteries.

Plaque can restrict blood flow, leading to chest pain, shortness of breath, and heart attacks. And calcium is a marker for plaque.

"The problem with cholesterol is that it indirectly measures health risks--you're looking at someone's blood to see what their arteries are

doing," says Dr. Shelton Thomas of Virginia Cardiovascular Specialists in Richmond. "Thirty percent of people who have heart attacks have normal cholesterol. But if you have normal cholesterol and a high calcium score, then we know that you're putting plaque in your arteries. It's the plaque that can kill you."

A heart scan--a painless procedure that takes about five minutes and costs $400--can tell you your calcium score, which ranges from

zero to the low thousands. (Healthy patients generally have scores below 100.)

In some states the test requires a prescription, but regardless, it is seldom covered by insurance. For a comparison of the two

types of scanners doctors use--MDCT or EBT--and for a directory of clinics in the U.S. that offer body-scan procedures, try scandirectory.com.

Chuck Marvin contributed to this article. This story was adapted from an article in the June issue of Fortune Small Business.