title: Planning of catheter interventions for pulmonary artery stenosis: improved measurement agreement with magnetic resonance angiography using identical angulations.
abstract: OBJECTIVE
  To evaluate the current disagreement between the gold standard X-ray angiography (XRA) and magnetic resonance angiography (MRA) for the measurement of peripheral pulmonary artery stenosis (PPAS).
  
  
  BACKGROUND
  MRA may help planning of catheter interventions for PPAS. However, there are sources of disagreement between XRA and MRA as measures are performed differently. We hypothesized that agreement may improve if identical angulation views are used.
  
  
  METHODS
  In this retrospective study, 17 patients were included. Four independent observers analyzed the pictures in three technique modalities: (1) XRA, (2) cross-sectional-MRA: reformatted to obtain the perpendicular cut-off view of the vessel, and (3) angulated-MRA: reformatted using the same angulations used in XRA. We measured: (a) minimal diameter at stenosis, (b) vessel diameter 1 cm proximal, and (c) 1 cm distal to the stenosis.
  
  
  RESULTS
  While in elliptical vessels cross-sectional-MRA provided both the larger and smaller diameter, XRA and angulated-MRA typically provided only the larger diameter due to projections. We found poor agreement between the smaller diameter in cross-sectional-MRA and XRA. XRA underestimate the diameter at the three locations (<15-22%). However, there was a good agreement between the larger cross-sectional-MRA diameter and XRA. This further improved if MRA images were reformatted with the identical angulations used in XRA (angulated-MRA).
  
  
  CONCLUSIONS
  Conventional cross-sectional-MRA measurements of PPAS only moderately agree with XRA. However, using identical angulations in MRA reduces the bias. Hence, MRA is a valuable tool for planning angulations and measurements of PPAS prior to catheter interventions.
authors.affiliation: Department of Paediatric Cardiology, Evelina Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, and Division of Imaging Sciences, King's College London, London, United Kingdom. isra.valverde@kcl.ac.uk
authors.forename: Israel
authors.initials: I
authors.lastname: Valverde
authors.forename: Victoria
authors.initials: V
authors.lastname: Parish
authors.forename: Tarique
authors.initials: T
authors.lastname: Hussain
authors.forename: Eric
authors.initials: E
authors.lastname: Rosenthal
authors.forename: Philipp
authors.initials: P
authors.lastname: Beerbaum
authors.forename: Thomas
authors.initials: T
authors.lastname: Krasemann
mesh_terms: D000293:Adolescent; D000328:Adult; D017130:Angioplasty; D001157:Arterial Occlusive Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D002932:Cineangiography; D003251:Constriction, Pathologic; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007223:Infant; D008131:London; D018810:Magnetic Resonance Angiography; D015588:Observer Variation; D018579:Patient Selection; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000000981:diagnostic imaging* / Q000473:pathology*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult