"Because of the many different ways to gather this important information, MRI can be used to identify or display almost every type of spinal tissue or pathology," said co-author Victor M. Haughton of the department of radiology at the University of Wisconsin Hospitals and Clinics. "The imaging sequence can be modified to meet many different clinical needs." Such needs encompass back pain, infection, tumors, trauma and vascular disease.
In terms of spinal applications, MRI is now being used to investigate vascular disorders, trauma, abnormal narrowing of the spinal canal, and degeneration of the intervertebral discs and of the joints that link vertebrae together. The MRI machine works by measuring the varying amounts of energy given off by such tissues as fat, muscle, spinal nerves and spinal fluid when their protons are excited by radio waves in the presence of a strong magnetic field.
Thus, MRI scans can provide detailed images of spinal vertebrae spaces, bone marrow, the spinal canal and surrounding soft tissues. And MRI doesn't pose a radiation risk to patients. The orthopedic evaluation also included a consideration of computed tomography (CT), a related imaging technology. It's good for patients for whom a strong magnetic field poses problems, such as people with pacemakers or nerve stimulators, or for those with severe claustrophobia. CT, however, involves some radiation exposure.
"The possibilities of magnetic resonance have not yet been realized," Haughton said. "It is a rapidly evolving field. When we need tools to identify a possible herniated disk, the simplest type of MR imaging or CT imaging can be used successfully. However, if you want to find out which disk is causing pain, which nerve is firing, which metabolites are present in abnormal amounts, or how well the spinal elements are functioning, MR will provide the answers."