The Plus-Size MRI Machine

As the percentage of obese Americans continues to rise, hospitals demand larger, more powerful imaging machines that can fit any patient and penetrate greater masses of tissue. Because body fat can disrupt the quality of images, companies also are developing software that can produce crisper scans without upping the doses of potentially harmful radiation.

The larger scanners are part of a growing trend in medical equipment, which include longer needles and sturdier beds to accommodate the needs of obese patients.

"The U.S. is the biggest market for us, so every product we build has the obese American patient in mind," said Bernd Montag, chief executive of Siemens AG's imaging division, which makes computed tomography, or CT, scanners to support patients well over 600 pounds, though its MRI machines remain smaller. "It more or less has turned into a design requirement."