FRIDAY, Nov. 20 (HealthDay News) -- Using a blood test to pinpoint the optimal timing of breast MRI scans in women with irregular menstrual cycles could reduce the need for repeat scans, U.S. researchers say.

Previous studies have found that performing breast MRI scans during the follicular phase (days 3 to14) of the menstrual cycle minimizes breast tissue enhancement.

"In practice, many clinicians scan premenopausal women who lack normal menstrual cycles without regard to the timing of their hormonal cycle. This can result in non-diagnostic exams and repeat scans," Dr. Richard L. Ellis, a radiologist at the Norma J. Vinger Center for Breast Care in Lacrosse, Wis., and lead author of the new study, said in a news release from the American College of Radiology/American Roentgen Ray Society.

In this study, Ellis and colleagues used blood tests to schedule MRI breast exams in 11 women with irregular menstrual cycles. The findings are published in the December issue of the American Journal of Roentgenology.

"None of the breast MRI scans performed in our small group of women resulted in high background enhancement of normal breast tissue requiring a repeat scan," Ellis said in the news release.

"Appropriate timing of a breast MRI examination for premenopausal women who do not have a normal menstrual cycle is a challenge. However, using existing science, we found that a simple blood test to determine a woman's serum progesterone concentration can aid in optimal timing of breast MRI. This is significant in an ever-increasing population of women requiring or eligible for breast MRI," he added.

More information

The American Cancer Society explains mammograms and other breast imaging procedures.