In late September 2022, Ryan Crownholm, a 46-year-old entrepreneur from Los Angeles, donned a pair of plush surgical scrubs and hopped onto a stainless-steel MRI table at Prenuvo, a fast-growing chain of body-scanning clinics. Crownholm, the founder of dirt-hauling startup DirtMatch, was undergoing an elective MRI, which cost him $2,500 and would generate a full 20-page set of diagnostics about his nervous, circulatory, digestive, urinary and musculoskeletal systems. “It felt like a high-end spa,” he said of the West Los Angeles location, which included tables loaded with herbal teas and protein bars.

Five days later, Crownholm’s primary care physician called with some bad news. “Your MRI showed an 8.25-centimeter renal cell carcinoma on your kidney,” the doctor informed him. After Crownholm underwent a computerized tomography scan at a hospital, the existence of the mass was confirmed, with his doctor estimating a 98% likelihood that it was malignant. The news landed like a bombshell. “What if my kids had to grow up without a dad?” Crownholm asked.

In November, surgeons successfully removed Crownholm’s kidney, and a biopsy confirmed he’d had stage 3 kidney cancer. “I dodged the bullet,” he said three months later with the cancer in remission. If the mass had been discovered a year later, his doctor told him, “we’d have had a very different conversation.”

Crownholm’s experience represented an extreme outcome for patients undergoing elective body scans. But for the majority of people shelling out for them, the scans offer something else: the ability to peer into the black box of your body and decrypt the messages it is sending you. For a target audience of affluent and tech-obsessed patients, a slew of new body diagnostics companies is offering the chance to “be the CEO of your own health.”