Nonbinary quantification technique accounting for myocardial infarct heterogeneity: Feasibility of applying percent infarct mapping in patients

Domenico Mastrodicasa; Gabriel A Elgavish; U Joseph Schoepf; Pal Suranyi; Marly van Assen; Moritz H Albrecht; Carlo N De Cecco; Rob J van der Geest; Rayphael Hardy; Cesare Mantini; L Parkwood Griffith; Balazs Ruzsics; Akos Varga-Szemes

doi:10.1002/jmri.25973

Nonbinary quantification technique accounting for myocardial infarct heterogeneity: Feasibility of applying percent infarct mapping in patients

J Magn Reson Imaging. 2018 Feb 15. doi: 10.1002/jmri.25973. Online ahead of print.

Authors

Affiliations

¹ Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA.
² Department of Neuroscience and Imaging, Section of Diagnostic Imaging and Therapy - Radiology Division, SS. Annunziata Hospital, "G. d'Annunzio" University, Chieti, Italy.
³ Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA.
⁴ University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands, Groningen, The Netherlands.
⁵ Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt, Germany.
⁶ Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
⁷ Department of Cardiology, Royal Liverpool and Broadgreen University Hospital, Liverpool, UK.

PMID: 29446527
DOI: 10.1002/jmri.25973

Abstract

Background: Binary threshold-based quantification techniques ignore myocardial infarct (MI) heterogeneity, yielding substantial misquantification of MI.

Purpose: To assess the technical feasibility of MI quantification using percent infarct mapping (PIM), a prototype nonbinary algorithm, in patients with suspected MI.

Study type: Prospective cohort POPULATION: Patients (n = 171) with suspected MI referred for cardiac MRI.

Field strength/sequence: Inversion recovery balanced steady-state free-precession for late gadolinium enhancement (LGE) and modified Look-Locker inversion recovery (MOLLI) T₁ -mapping on a 1.5T system.

Assessment: Infarct volume (IV) and infarct fraction (IF) were quantified by two observers based on manual delineation, binary approaches (2-5 standard deviations [SD] and full-width at half-maximum [FWHM] thresholds) in LGE images, and by applying the PIM algorithm in T₁ and LGE images (PIM_T1 ; PIM_LGE ).

Statistical test: IV and IF were analyzed using repeated measures analysis of variance (ANOVA). Agreement between the approaches was determined with Bland-Altman analysis. Interobserver agreement was assessed by intraclass correlation coefficient (ICC) analysis.

Results: MI was observed in 89 (54.9%) patients, and 185 (38%) short-axis slices. IF with 2, 3, 4, 5SDs and FWHM techniques were 15.7 ± 6.6, 13.4 ± 5.6, 11.6 ± 5.0, 10.8 ± 5.2, and 10.0 ± 5.2%, respectively. The 5SD and FWHM techniques had the best agreement with manual IF (9.9 ± 4.8%) determination (bias 1.0 and 0.2%; P = 0.1426 and P = 0.8094, respectively). The 2SD and 3SD algorithms significantly overestimated manual IF (9.9 ± 4.8%; both P < 0.0001). PIM_LGE measured significantly lower IF (7.8 ± 3.7%) compared to manual values (P < 0.0001). PIM_LGE , however, showed the best agreement with the PIM_T1 reference (7.6 ± 3.6%, P = 0.3156). Interobserver agreement was rated good to excellent for IV (ICCs between 0.727-0.820) and fair to good for IF (0.589-0.736).

Data conclusion: The application of the PIM_LGE technique for MI quantification in patients is feasible. PIM_LGE , with its ability to account for voxelwise MI content, provides significantly smaller IF than any thresholding technique and shows excellent agreement with the T₁ -based reference.

Level of evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.

Keywords: T1 mapping; late gadolinium enhancement; magnetic resonance imaging; myocardial infarct heterogeneity; myocardial infarct quantification; percent infarct mapping.