title: Facet tropism: comparison of plain film and computed tomography examinations.
abstract: This study compares the findings of plain film X-ray and computed CT examination in the diagnosis of facet orientation and the presence of tropism. Twenty consecutive patients having lumbar disc disease with sciatica were studied utilizing plain X-ray as well as CT scanning. A chiropractic radiologist read the films to determine if facet facings were sagittally, semi-sagittally or coronally oriented on both CT and plain X-ray study. CT was accepted as the most accurate method to determine the true facet orientation, and plain X-ray interpretation of facet orientation was compared to the CT reading. There was a statistically significant relationship in diagnosing tropism between plain film X-ray and CT readings, with a predictive accuracy that ranged from 58-84% across the three segmental levels. However, the exact concordance of plain film X-ray and CT readings for right and left facet facings was very low. This raises the question of how the profession defines diagnostic accuracy.
authors.affiliation: Department of Sociology and Anthropology, Indiana University, Purdue University, Fort Wayne 46805.
authors.forename: J M
authors.initials: JM
authors.lastname: Cox
authors.forename: D D
authors.initials: DD
authors.lastname: Aspegren
authors.forename: K K
authors.initials: KK
authors.lastname: Trier
mesh_terms: D001416:Back Pain / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D005069:Evaluation Studies as Topic; D006801:Humans; D008159:Lumbar Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging; D011859:Radiography / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000592:standards*