MAGNETIC-RESONANCE-IMAGING OF VERTEBRAL COMPRESSION FRACTURES

In this study, magnetic resonance imaging (MRI) was used to analyze th e signal intensity and vascularity of compression fractures of vertebr ae in 74 patients. The possibility of nonunion was assessed according to the specific image findings and clinical presentation. All patients had chronic back pain for more than 3 months and compression fracture s of the vertebrae initially demonstrated by plain radiography. Pre-en hanced T1 and T2-weighted images (*multiplaner gradient recall sequen ce) and postenhanced MRI were obtained. Images were divided into three categories according to the signal intensity of the fractured vertebr ae such as hyperintensity (n = 35), hypointensity (n = 24) on T1-weigh ted image and necrotic ripe compression fractures of the vertebrae (n = 15). Of the 15 necrotic-type cases, 13 disclosed ''fluid''-containin g space at the collapsed vertebrae and two showed ''air''-containing s pace at the vertebral body. We believe that these findings are pathogn omonic signs of nonunion of the collapsed vertebrae. Surgical specimen s were obtained from the four patients whose vertebrae showed necrosis and granulation tissue. After posterior spinal instrumentation, the c ollapsed vertebral body regained the height and presence of the open e nd-plate of the vertebra on postoperative lateral radiography. Tile su perior capabilities of MRI offers useful criteria that make the diagno sis of nonunion in compression fractures of the spine possible. Thus, a space with ''fluid'' or ''air'' collection at the anterior aspect of a collapsed vertebra as well as strong enhancement with Gd-DTPA at th e posterior aspect of the collapsed vertebra may be considered to be p athognomonic signs of nonunion of the fractured vertebra.