title: Assessment of right atrium volume by conventional CT or MR techniques: Which modality resembles in vivo reality?
abstract: OBJECTIVE
  Right atrial volume (RAV) is a prognostic factor of the right heart function. This retrospective study evaluates the comparability of computed tomography (CT) and magnetic resonance imaging (MRI) for right atrial volumetry with conventional planimetric and diametric methods.
  
  
  METHODS
  29 retrospectively included patients (18 male, 47±12years) underwent CT and 1.5 Tesla MRI within 17±20days. RAV was measured using biplane and ellipsoid method (MRI and CT) and Simpson's method (CT). For interobserver comparison measurements were carried out by two observers. Pearson's correlation, Lin's concordance coefficient, and Bland-Altman statistics were calculated.
  
  
  RESULTS
  There is a correlation of RAV between CT and MRI, r [ellipsoid]=0.65; r [biplane]=0.64 (p<0.001). MRI volumes were significantly lower than CT volumes, [mean±SD] 43±19ml versus 27±9ml, (p<0.002). There was a close interobserver correlation (CT: r=0.83, MRI: r=0.73; p<0.001) but a relatively wide range in Bland-Altman analysis; limits of agreement from ±13ml up to ±29ml.
  
  
  CONCLUSIONS
  Compared to left atrial volumes, a higher variability was found for RAV values both in interobserver statistiscs and in intermodality comparison. Complex shape of the right atrium, artifacts due to contrast material (CT), high venous return in inspiration (CT), high flow contrast media administration (CT) and increased heart rate (MRI) might cause these clinically relevant variations.
authors.affiliation: Philipps University of Marburg, Diagnostic and Interventional Radiology, Baldingerstraße, 35043 Marburg, Germany. Electronic address: rheinhei@med-uni-marburg.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Rheinheimer
authors.affiliation: Philipps University of Marburg, Diagnostic and Interventional Radiology, Baldingerstraße, 35043 Marburg, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Reh
authors.affiliation: Philipps University of Marburg, Diagnostic and Interventional Radiology, Baldingerstraße, 35043 Marburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Figiel
authors.affiliation: Philipps University of Marburg, Diagnostic and Interventional Radiology, Baldingerstraße, 35043 Marburg, Germany.
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D006332:Cardiomegaly / Q000000981:diagnostic imaging / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods; D015588:Observer Variation; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: Biplane; Computed tomography; Magnetic resonance imaging; Right atrium volume; Simpson