title: Center differences in a study of the efficacy of B-scan ultrasound.
abstract: As part of a four year NIH-sponsored multi-center trial to evaluate the efficacy of B-mode ultrasound imaging of carotid atherosclerosis, multiple readings of B-scan and angiographic studies of 234 vessels were obtained to permit intramodality assessment of within-reader and between-reader variation. All readers were obligated to adhere to a common protocol that was monitored both onsite and at a central coordinating facility. Among the five participating centers, the within-reader correlation coefficients for measurement of minimal residual lumen ranged from 0.85 to 0.99 for angiography and 0.62 to 0.93 for B-scan. Between-reader correlation coefficients for minimal residual lumen varied from 0.50 to 0.98 for angiography and 0.59 to 0.87 for B-scan. Analysis of center differences for other measurements demonstrated similar variations. This suggests that center differences may have a significant impact upon results of multi-center trials even when identical protocols are utilized.
authors.affiliation: Department of Radiology, New England Deaconess Hospital, Boston, Massachusetts.
authors.forename: D H
authors.initials: DH
authors.lastname: O'Leary
authors.forename: A V
authors.initials: AV
authors.lastname: Rao
mesh_terms: D001161:Arteriosclerosis / Q000000981:diagnostic imaging*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography; D006801:Humans; D015588:Observer Variation; D014463:Ultrasonography