By Li Hongmei

The first full-face transplant patients in the U.S. are growing into their new appearances - literally.

Medical imaging shows new blood vessel networks have formed, connecting transplanted skin with the patients' facial tissue, a finding that may help improve future face transplant surgeries, doctors announced Wednesday.

Dallas Wiens, the first U.S. man to get a full face transplant, is a remarkable example of that success. The 28-year-old attended Wednesday's annual meeting of the Radiological Society of North America with his new wife and golden retriever guide dog. Despite visible facial scars from the March 2011 surgery, he looks and sounds like a recovered man.

"My entire life is a miracle," Wiens said at a news conference.

His face was burned off in a 2008 painting accident at his church, when his head hit a high-voltage wire.

After surgery, Wiens lived for two years with no facial features and just a slit for a mouth, until his transplant at Boston's Brigham and Women's Hospital.

Imaging studies on Wiens and two other full-face transplants done at the hospital in 2011 show that a network of new blood vessels had formed just a year after the operations. A fourth full-face transplant was performed at the hospital earlier this year.

The same thing typically happens with other transplants and it helps ensure their success by boosting blood flow to the donor tissue. But doctors say this is the first time it has happened with full-face transplants.