Myocardial Edema, Blood Flow, and Contractility in Takotsubo Syndrome: Comparative Evaluation with CMR and PET.

BACKGROUND: Takotsubo syndrome (TTS) features transient left ventricular (LV) dysfunction, often with myocardial edema and impaired coronary microcirculation. The relationships between myocardial edema, blood flow, and LV contractility remain unclear. We retrospectively examined these associations using cardiac magnetic resonance (CMR) and positron emission tomography (PET). METHODS: TTS patients were included if they underwent CMR and PET within 30 days of admission and ≤ 7 days apart. Correlations between CMR-derived T2 and PET-derived stress myocardial blood flow (MBF), myocardial flow reserve (MFR), and coronary vascular resistance (CVR) were analyzed regionally and globally. For regional analysis, LV was divided into basal, mid, and apical segments, each classified by wall motion (normal, hypokinesis, akinesis, dyskinesis) to compare T2, stress MBF, and CVR. Global analyses included correlations using global values and longitudinal gradients. Parameters were also compared with cine CMR-derived global longitudinal strain (GLS). RESULTS: Of 67 patients screened, 43 (mean age 69 years; 98% female) were included, yielding 129 regions: 62 normokinetic (48%), 14 hypokinetic (11%), 44 akinetic (34%), and 9 dyskinetic (7%). Regionally, higher T2 was associated with lower stress MBF and MFR and higher CVR. T2, stress MBF, and CVR varied stepwise with wall-motion severity. Globally, both T2 and longitudinal T2 gradients correlated with stress MBF and CVR. Longitudinal gradients of T2, stress MBF, and CVR were significantly associated with GLS. CONCLUSIONS: In TTS, myocardial edema is associated with reduced stress MBF and higher CVR, and these abnormalities track with LV contractility. Longitudinal gradients may provide greater clinical relevance than global measures.