title: Automated analysis of atrial late gadolinium enhancement imaging that correlates with endocardial voltage and clinical outcomes: a 2-center study.
abstract: BACKGROUND
  For late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) assessment of atrial scar to guide management and targeting of ablation in atrial fibrillation (AF), an objective, reproducible method of identifying atrial scar is required.
  
  
  OBJECTIVE
  To describe an automated method for operator-independent quantification of LGE that correlates with colocated endocardial voltage and clinical outcomes.
  
  
  METHODS
  LGE CMR imaging was performed at 2 centers, before and 3 months after pulmonary vein isolation for paroxysmal AF (n = 50). A left atrial (LA) surface scar map was constructed by using automated software, expressing intensity as multiples of standard deviation (SD) above blood pool mean. Twenty-one patients underwent endocardial voltage mapping at the time of pulmonary vein isolation (11 were redo procedures). Scar maps and voltage maps were spatially registered to the same magnetic resonance angiography (MRA) segmentation.
  
  
  RESULTS
  The LGE levels of 3, 4, and 5SDs above blood pool mean were associated with progressively lower bipolar voltages compared to the preceding enhancement level (0.85 ± 0.33, 0.50 ± 0.22, and 0.38 ± 0.28 mV; P = .002, P < .001, and P = .048, respectively). The proportion of atrial surface area classified as scar (ie, >3 SD above blood pool mean) on preablation scans was greater in patients with postablation AF recurrence than those without recurrence (6.6% ± 6.7% vs 3.5% ± 3.0%, P = .032). The LA volume >102 mL was associated with a significantly greater proportion of LA scar (6.4% ± 5.9% vs 3.4% ± 2.2%; P = .007).
  
  
  CONCLUSIONS
  LA scar quantified automatically by a simple objective method correlates with colocated endocardial voltage. Greater preablation scar is associated with LA dilatation and AF recurrence.
authors.affiliation: Imperial College London and Imperial College Healthcare NHS Trust, London, United Kingdom.
authors.forename: L C
authors.initials: LC
authors.lastname: Malcolme-Lawes
authors.forename: C
authors.initials: C
authors.lastname: Juli
authors.forename: R
authors.initials: R
authors.lastname: Karim
authors.forename: W
authors.initials: W
authors.lastname: Bai
authors.forename: R
authors.initials: R
authors.lastname: Quest
authors.forename: P B
authors.initials: PB
authors.lastname: Lim
authors.forename: S
authors.initials: S
authors.lastname: Jamil-Copley
authors.forename: P
authors.initials: P
authors.lastname: Kojodjojo
authors.forename: B
authors.initials: B
authors.lastname: Ariff
authors.forename: D W
authors.initials: DW
authors.lastname: Davies
authors.forename: D
authors.initials: D
authors.lastname: Rueckert
authors.forename: D P
authors.initials: DP
authors.lastname: Francis
authors.forename: R
authors.initials: R
authors.lastname: Hunter
authors.forename: D
authors.initials: D
authors.lastname: Jones
authors.forename: R
authors.initials: R
authors.lastname: Boubertakh
authors.forename: S E
authors.initials: SE
authors.lastname: Petersen
authors.forename: R
authors.initials: R
authors.lastname: Schilling
authors.forename: P
authors.initials: P
authors.lastname: Kanagaratnam
authors.forename: N S
authors.initials: NS
authors.lastname: Peters
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000473:pathology* / Q000601:surgery; D017115:Catheter Ablation / Q000379:methods*; D002921:Cicatrix / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006325:Heart Atria / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009942:Organometallic Compounds; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; D005682:Gadolinium
keywords: 2-dimensional; 2D; AF; Atrial fibrillation; CMR; Delayed-enhancement magnetic resonance imaging; ECG; LA; LGE; MRA; Magnetic resonance angiography; PAF; RF; Radiofrequency ablation; SD; atrial fibrillation; cardiovascular magnetic resonance; electrocardiogram; late gadolinium enhancement; left atrial/atrium; paroxysmal atrial fibrillation; radiofrequency; standard deviation