An ultrasound of one's thigh or shoulder muscle could help detect insulin resistance, a stage that often precedes prediabetes, a study suggests.

Ultrasounds of muscles of 25 patients -- who were also checked for insulin resistance -- showed that their muscles appear "unusually bright", lead author Steven Soliman, director of musculoskeletal radiology fellowship at the University of Michigan, US, said.

"We found it interesting that most of these patients (with bright ultrasound images) have type 2 diabetes. Seeing this pattern, we often thought, 'This patient must have diabetes'," Soliman said.