title: Diagnostic Accuracy of 4 Commercially Available Semiautomatic Packages for Carotid Artery Stenosis Measurement on CTA.
abstract: OBJECTIVE
  Semiautomatic measurement of ICA stenosis potentially increases observer reproducibility. In this study, we assessed the diagnostic accuracy and interobserver reproducibility of a commercially available semiautomatic ICA stenosis measurement on CTA and estimated the agreement among different software packages.
  
  
  METHODS
  We analyzed 141 arteries from 90 patients with TIA or ischemic stroke. Manual stenosis measurements were performed by 2 neuroradiologists. Semiautomatic measurements by using 4 methods (3mensio and comparable software from Philips, TeraRecon, and Siemens) were performed by 2 observers. Diagnostic accuracy was estimated by comparing semiautomatic with manual measurements. Interobserver reproducibility and agreement between different packages was assessed by calculation of the intraclass correlation coefficient and Bland-Altman 95% limits of agreement. False-negative classifications were retrospectively inspected by a neuroradiologist.
  
  
  RESULTS
  There was no significant difference in the diagnostic performance of the 4 semiautomatic methods. The sensitivity for detecting ≥50% and ≥70% degree of stenosis was between 76% and 82% and 46% and 62%, respectively. Specificity and overall diagnostic accuracy were between 92% and 97% and 85% and 90%, respectively. The interobserver intraclass correlation coefficient was between 0.83 and 0.96 for semiautomatic measurements and 0.81 for manual measurement. The limits of agreement between each pair of semiautomatic packages ranged from -18%-24% to -33%-31%. False-negative classifications were caused by ulcerative plaques and observer variation in stenosis and reference measurements.
  
  
  CONCLUSIONS
  Semiautomatic methods have a low-to-good sensitivity and a good specificity and overall diagnostic accuracy. The high interobserver reproducibility makes semiautomatic stenosis measurement valuable for clinical practice, but semiautomatic measurements should be checked by an experienced radiologist.
authors.affiliation: From the Departments of Radiology (J.B., H.A.M., M.K., R.v.d.B., C.B.L.M.M.) j.borst@amc.uva.nl.
authors.forename: J
authors.initials: J
authors.lastname: Borst
authors.affiliation: From the Departments of Radiology (J.B., H.A.M., M.K., R.v.d.B., C.B.L.M.M.) Biomedical Engineering and Physics (H.A.M.).
authors.forename: H A
authors.initials: HA
authors.lastname: Marquering
authors.affiliation: From the Departments of Radiology (J.B., H.A.M., M.K., R.v.d.B., C.B.L.M.M.).
authors.forename: M
authors.initials: M
authors.lastname: Kappelhof
authors.affiliation: Department of Radiology (T.Z., A.C.v.D., A.v.d.L.), Erasmus University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Zadi
authors.affiliation: Department of Radiology (T.Z., A.C.v.D., A.v.d.L.), Erasmus University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: A C
authors.initials: AC
authors.lastname: van Dijk
authors.affiliation: Neurology (P.J.N.), Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: Nederkoorn
authors.affiliation: From the Departments of Radiology (J.B., H.A.M., M.K., R.v.d.B., C.B.L.M.M.).
authors.forename: R
authors.initials: R
authors.lastname: van den Berg
authors.affiliation: Department of Radiology (T.Z., A.C.v.D., A.v.d.L.), Erasmus University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: van der Lugt
authors.affiliation: From the Departments of Radiology (J.B., H.A.M., M.K., R.v.d.B., C.B.L.M.M.).
authors.forename: C B L M
authors.initials: CB
authors.lastname: Majoie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020520:Brain Infarction / Q000175:diagnosis*; D016893:Carotid Stenosis / Q000175:diagnosis*; D002533:Cerebral Angiography; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002546:Ischemic Attack, Transient / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012984:Software; D014057:Tomography, X-Ray Computed