title: MR feature tracking in patients with MRI-conditional pacing systems: The impact of pacing.
abstract: To develop feature tracking (FT) software to perform strain analysis on conventional (nontagged) cardiac magnetic resonance imaging (MRI) function images. With the advent of MRI-conditional pacemaker systems, effects of cardiac pacing on myocardial strain can be studied using MR. In this study the impact of pacing on left ventricular (LV) strain was investigated using MR-FT in patients with an MRI-conditional cardiac implantable electronic device (CIED).
  
  
  
  FT was performed on 32 1.5T MR studies (16 patients with an MRI-conditional CIED and 16 control patients with normal scans). Short- and long-axis steady state free precession (SSFP) cines were used for the FT analysis. Strain was assessed using CVI(42) software (Circle Cardiovascular Imaging, Alberta, Canada). In addition, the intra- and interobserver variability was determined using the intraclass correlation coefficient.
  
  
  
  Of the 16 patients with an MRI-conditional CIED, five patients were paced during the MRI exam. Despite the occasional presence of susceptibility artifacts induced by the CIED, radial, circumferential, and longitudinal strain parameters could be derived for all patients. Peak radial strain and peak circumferential strain were reduced during pacing when compared to the control group; for radial strain: 20.1 ± 4.7% vs. 33.1 ± 6.9%, P < 0.001, and for circumferential strain -7.5 ± 3.5% vs. -14.9 ± 3.2%, P < 0.05. Peak strain parameters were reproducible on an intra- and interobserver level.
  
  
  
  MR-FT is feasible in patients with an MRI-conditional CIED and can be used to quantify regional wall motion. J. MAGN. RESON. IMAGING 2016;44:964-971.
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, The Hague, The Netherlands. a.vandergraaf@hagaziekenhuis.nl.
authors.forename: A W Maurits
authors.initials: AW
authors.lastname: van der Graaf
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, The Hague, The Netherlands.
authors.forename: Pranav
authors.initials: P
authors.lastname: Bhagirath
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, The Hague, The Netherlands.|Reinier de Graaf Hospital, Delft, The Netherlands.
authors.forename: Mike G
authors.initials: MG
authors.lastname: Scheffer
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, The Hague, The Netherlands.
authors.forename: Ramon Robles
authors.initials: RR
authors.lastname: de Medina
authors.affiliation: Department of Cardiology, Haga Teaching Hospital, The Hague, The Netherlands.
authors.forename: Marco J W
authors.initials: MJ
authors.lastname: Götte
mesh_terms: D016880:Anisotropy; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects* / Q000379:methods; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033081:Shear Strength; D013314:Stress, Mechanical; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology*
keywords: cardiac pacing effects; magnetic resonance feature tracking; myocardial strain; regional myocardial strain