title: Differences in quantitative assessment of myocardial scar and gray zone by LGE-CMR imaging using established gray zone protocols.
abstract: Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging is the gold standard for myocardial scar evaluation. Heterogeneous areas of scar ('gray zone'), may serve as arrhythmogenic substrate. Various gray zone protocols have been correlated to clinical outcomes and ventricular tachycardia channels. This study assessed the quantitative differences in gray zone and scar core sizes as defined by previously validated signal intensity (SI) threshold algorithms. High quality LGE-CMR images performed in 41 cardiomyopathy patients [ischemic (33) or non-ischemic (8)] were analyzed using previously validated SI threshold methods [Full Width at Half Maximum (FWHM), n-standard deviation (NSD) and modified-FWHM]. Myocardial scar was defined as scar core and gray zone using SI thresholds based on these methods. Scar core, gray zone and total scar sizes were then computed and compared among these models. The median gray zone mass was 2-3 times larger with FWHM (15 g, IQR: 8-26 g) compared to NSD or modified-FWHM (5 g, IQR: 3-9 g; and 8 g. IQR: 6-12 g respectively, p < 0.001). Conversely, infarct core mass was 2.3 times larger with NSD (30 g, IQR: 17-53 g) versus FWHM and modified-FWHM (13 g, IQR: 7-23 g, p < 0.001). The gray zone extent (percentage of total scar that was gray zone) also varied significantly among the three methods, 51 % (IQR: 42-61 %), 17 % (IQR: 11-21 %) versus 38 % (IQR: 33-43 %) for FWHM, NSD and modified-FWHM respectively (p < 0.001). Considerable variability exists among the current methods for MRI defined gray zone and scar core. Infarct core and total myocardial scar mass also differ using these methods. Further evaluation of the most accurate quantification method is needed.
authors.affiliation: Maryland Arrhythmia and Cardiology Imaging Group (MACIG), University of Maryland, Baltimore, MD, USA.
authors.forename: Olurotimi
authors.initials: O
authors.lastname: Mesubi
authors.forename: Kelechi
authors.initials: K
authors.lastname: Ego-Osuala
authors.forename: Jean
authors.initials: J
authors.lastname: Jeudy
authors.forename: James
authors.initials: J
authors.lastname: Purtilo
authors.forename: Stephen
authors.initials: S
authors.lastname: Synowski
authors.forename: Ameer
authors.initials: A
authors.lastname: Abutaleb
authors.forename: Michelle
authors.initials: M
authors.lastname: Niekoop
authors.forename: Mohammed
authors.initials: M
authors.lastname: Abdulghani
authors.forename: Ramazan
authors.initials: R
authors.lastname: Asoglu
authors.forename: Vincent
authors.initials: V
authors.lastname: See
authors.forename: Anastasios
authors.initials: A
authors.lastname: Saliaris
authors.forename: Stephen
authors.initials: S
authors.lastname: Shorofsky
authors.forename: Timm
authors.initials: T
authors.lastname: Dickfeld
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001331:Automation; D009202:Cardiomyopathies / Q000473:pathology*; D002921:Cicatrix / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D005355:Fibrosis; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA