144. Recognizing patients in whom CT-myelography detects additional level of stenosis compared to MRI

Abstract

<h3>BACKGROUND CONTEXT</h3> In patients with lumbar spinal stenosis, it is crucial for clinicians to identify all symptomatic levels. Prior studies have demonstrated that CT-myelography has a greater sensitivity in revealing stenosis (94.4%) compared to MRI (75.9%). CT-myelograms demonstrate weight-bearing changes as opposed to single position and single time point changes on MRI. However, CT-myelography is invasive, requiring injection of contrast dye into the thecal sac. <h3>PURPOSE</h3> The purpose of this study is to identify patients in whom additional levels of stenosis are likely to be recognized by a CT-myelogram following an MRI scan. <h3>STUDY DESIGN/SETTING</h3> Retrospective observational cohort at a single multi-surgeon spine center. <h3>PATIENT SAMPLE</h3> Patients ≥45 years old who had an MRI followed by a CT-myelogram within 6 months with a diagnosis of stenosis, spondylolisthesis, or degenerative scoliosis. <h3>OUTCOME MEASURES</h3> Additional levels of moderate to severe stenosis identified on CT-myelogram vs MRI. <h3>METHODS</h3> Medical records were reviewed to collect standard demographic and surgical data and to note if patients were deemed to have single-level or multi-level stenosis clinically. MRIs and CT-Myelograms obtained within six months of each other were reviewed and each lumbar level was recorded as mild, moderate, or severe based on the radiologist's report. Fisher's exact test was performed with change in recorded level of stenosis from MRI to CT-Myelogram as the primary outcome of interest. <h3>Results</h3> Of 207 patients, 139 (67%) had clinically reported multilevel stenosis and 68 (33%) had single-level stenosis. CT-Myelogram identified a greater proportion of additional stenotic levels in patients with clinically reported multilevel stenosis (80/139, 58%) compared to patients with single-level stenosis (27/68, 40%, p=0.018). When classifying patients based on MRI findings of stenosis instead of clinical diagnosis, 90 (43%) patients had multi-level stenosis, and 117 (56%) had single-level stenosis. In patients with radiologist-reported multilevel stenosis, CT-myelogram also identified a greater proportion of additional stenotic levels (55/90, 61%) compared to patients with radiologist-reported single level stenosis (52/117, 44%, p=0.025). <h3>Conclusions</h3> CT myelography is significantly more likely to provide valuable additional information in patients with multilevel stenosis as compared to patients with single level stenosis. This finding was consistent regardless of whether the distinction of single-level or multilevel stenosis was determined by clinical diagnosis or based solely off the MRI report. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.