This article reviews the imaging findings in spondylolysis, which represents a stress fracture of the pars interarticularis that is secondary to chronic low-grade trauma. The incidence of spondylolysis in the general population is approximately 6%, but it reaches 63% in those engaging in certain sporting activities. In a symptomatic patient, the radiologist may be asked to determine whether a lysis is present and, if so, whether it is the cause of symptoms. The first question is usually answered by radiography of good technical quality. CT, performed with a reverse gantry angle technique and thin sections, is the imaging modality of choice for identifying radiographically occult lysis. Several imaging pitfalls render MRI less sensitive than CT for directly visualizing pars interarticularis defects (regional degenerative changes and sclerosis). MR is the technique of choice, however, for identifying nerve root compression due to hypertrophic tissue filling the pars defect, which is expanded in the vertical plane with no modification of the epidural fat surrounding the nerve root. Determining whether spondylolysis is the cause of a patient's pain is more difficult. Positive single-photon emission CT (SPECT) may provide this distinction.
|Number of pages||14|
|Publication status||Published - Mar 2001|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging