¹³N-ammonia positron emission tomography-derived endocardial strain for the assessment of ischemia using feature-tracking in high-resolution cine imaging

Background: Assessing endocardial strain using a single ¹³N-ammonia positron emission tomography (PET) scan would be clinically useful, given the association between ischemia and myocardial deformation. However, no software has been developed for strain analysis using PET. We evaluated the clinical potential of feature tracking-derived strain values measured using PET, based on associations with the myocardial flow reserve (MFR).

Methods and results: This retrospective study included 95 coronary artery disease patients who underwent myocardial ¹³N-ammonia PET. Semi-automatic measurements were made using a feature-tracking technique during myocardial cine imaging, and values were calculated using a 16-segment model. Adenosine-stressed global circumferential strain (CS) and global longitudinal strain (LS) values were compared with global MFR values. Stressed and resting global strain values were also compared. Global strain values were significantly lower in 39 patients with abnormal MFRs [< 2.0] than in 56 patients with normal MFRs [≥ 2.0]. The global CS values in the stressed state were significantly decreased than the resting state values in patients with abnormal MFRs.

Conclusions: This study applied endocardial feature-tracking to ¹³N-ammonia PET, and the results suggested that blood flow and myocardial motility could be clinically assessed in ischemic patients using a single PET scan.