title: The effects of extracellular contrast agent (Gadobutrol) on the precision and reproducibility of cardiovascular magnetic resonance feature tracking.
abstract: Today feature tracking (FT) is considered to be a robust assessment tool in cardiovascular magnetic resonance (CMR) for strain assessment. The FT algorithm is dependent on a high contrast between blood pool and myocardium. Extracellular contrast agents decrease blood-myocardial contrast in SSFP images and thus might affect FT results. However, in a routine CMR scan, SSFP-cine images including short axis views are partly acquired after contrast agent injection. The aim of this study was to investigate the effect of extracellular contrast agent (Gadobutrol) (CA) on the precision and reproducibility of the feature tracking algorithm.
  
  
  
  A total of 40 patient volunteers (mean age 51.2 ± 19 years; mean LVEF 61 ± 9 %) were scanned in supine position on a clinical 1.5 T MR scanner (Philips Ingenia). SSFP-cine images in midventricular short axis view (SA) as well as horizontal long axis view (HLA) were acquired before and 10-15 min after injection of a double dose Gadobutrol. FT derived systolic circumferential and longitudinal strain parameters were then calculated for pre- and post-contrast images.
  
  
  
  FT derived midventricular peak systolic circumferential strain (PSCS) (-24.8 ± 6.4 % vs. -20.4 ± 6.3 %), apical PSCS (-28.67 ± 6.5 % vs. -24.06 ± 8.5 %), basal PSCS (-24.42 % ± 6.5 vs. -20.68 ± 7.1 %), peak systolic longitudinal strain (-19.57 ± 3.3 % vs. -17.24 ± 4.1 %), midventricular epicardial PSCS (-9.84 ± 3.4 % vs. -8.13 ± 3.4 %) , midventricular PSCS-rate (-1.52 ± 0.4 vs. -1.28 ± 0.5) and peak diastolic circumferential strain rate (1.4 ± 0.5 vs. 1.05 ± 0.5) were significantly reduced after CA application. Post CA strain assessment showed higher intra- and interobserver variability. Pre-CA: intraobserver: mean 0.21, Limits of agreement (LoA) -2.8 and 3.2; interobserver: mean 0.64, LoA -2.8 and 4.1. Post-CA: intraobserver: mean -0.11, LoA -5.1 to 4.9; interobserver: mean 4.93 LoA 2.4 to 12.2.
  
  
  
  The FT algorithm is dependent on a high contrast between blood and myocardium. Post CA strain results are significantly lower and less reproducible than pre-CA strain results.
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str.25, 53127, Bonn, Germany.
authors.forename: Daniel L R
authors.initials: DL
authors.lastname: Kuetting
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str.25, 53127, Bonn, Germany.
authors.forename: Darius
authors.initials: D
authors.lastname: Dabir
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str.25, 53127, Bonn, Germany.
authors.forename: Rami
authors.initials: R
authors.lastname: Homsi
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str.25, 53127, Bonn, Germany.
authors.forename: Alois M
authors.initials: AM
authors.lastname: Sprinkart
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str.25, 53127, Bonn, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Luetkens
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str.25, 53127, Bonn, Germany.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Schild
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str.25, 53127, Bonn, Germany. daniel.thomas@ukb.uni-bonn.de.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Thomas
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001696:Biomechanical Phenomena; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D015588:Observer Variation; D009942:Organometallic Compounds / Q000008:administration & dosage*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013318:Stroke Volume; D016277:Ventricular Function, Left
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
keywords: Cardiovascular magnetic resonance; Feature tracking; Gadobutrol; Myocardial strain; Robustness