Magnetic resonance spectroscopy, a form of MRI technology that generates spectrums rather than images, may be the definitive tool for diagnosing bipolar disorder, according to a study presented at the Radiological Society of North America annual meeting in Chicago. With MR spectroscopy, Mayo Clinic researchers detected significant differences between the brain chemistries of 21 people already diagnosed with bipolar disorder and 21 people without the disorder. According to preliminary findings, certain metabolite levels differed significantly in four areas of the brain that control behavior. With luck, MR spectroscopy could become the gold standard for diagnosis of the disorder in two to three years, said John Port, assistant professor of radiology and a consultant at Mayo Clinic, Rochester, Minn. Bipolar, or manic-depressive, disorder affects approximately 2.3 million Americans, and many patients go undiagnosed for years. The disorder is now diagnosed based on symptoms and family history.
In other RSNA news, radiologists reported a significant increase in the number of diagnostic imaging tests performed by nonradiologists. An analysis of procedure, specialty and location codes from Medicare between 1997 and 2002 found that utilization rose 11.6% among radiologists, 23.5% among all nonradiologists and 42.2% among cardiologists specifically. Medicare reimbursement for MRI services increased six times the rate for orthopedic surgeons than for radiologists during the same period. The proportion of noninvasive diagnostic imaging tests performed at hospitals fell to 28.4% from 33.6% while rising to 32.6% from 28.1% at private offices and imaging centers. -- by Cinda Becker
