JMIR Publications

ABSTRACT

Background:

Myocardial infarction (location and extent of infarction) can be determined by late enhancement cardiac magnetic resonance (CMR) imaging, which requires injection of potentially harmful gadolinium-based contrast agent (GBCA). Alternatively, emerging research in the area of myocardial strain, has shown a potential to identify myocardial infarction using strain values.

Objective:

To identify the location of myocardial infarction, by developing an applied algorithmic method of circumferential strain values, which are derived through a novel Hierarchical Template Matching (HTM) method.

Methods:

HTM-based circumferential strain (HTM-CS) H-spread from end-diastole to end-systole is used to develop an applied method. Grid-tagging magnetic resonance imaging is used to calculate strain values in left ventricular myocardium, and the 16-segment American heart association model is followed. The dataset is used in a k-fold cross-validation manner to estimate the percentage reduction of H-spread among infarcted and non-infarcted left ventricular segments. Forty-three subjects (38 myocardial infarction, 5 healthy) who underwent CMR imaging, are retrospectively selected. Infarcted segments, detected by this method, are validated by comparison with late enhancement CMR, and diagnostic performance of the applied algorithmic method is evaluated with receiver operating characteristics (ROC) curve test.

Results:

The H-spread of the circumferential strain is reduced in infarcted segments compared to non-infarcted segments of LV. The reductions are 30% in basal, 30% in mid-ventricular, and 20% in apical LV segments. The diagnostic accuracy of detections, using the reported method, is represented by the area under curve (AUC) values, which are 0.8551, 0.8263 and 0.8733 for basal, mid-ventricular, and apical slices, respectively, demonstrating good agreement with the late-gadolinium enhancement-based detections.

Conclusions:

The proposed applied algorithmic method has the potential to accurately identify the location of infarcted LV segments, without administration of late-gadolinium enhancement. Such an approach adds the potential to safely identify myocardial infarction, potentially reduce patient scanning time and extend the utility of CMR in patients, who are contraindicated to the use of GBCA.