Simultaneous Positron Emission Tomography/Magnetic Resonance Imaging Identifies Sustained Regional Abnormalities in Cardiac Metabolism and Function in Stress-Induced Transient Midventricular Ballooning Syndrome

Abstract

A 70-year-old white woman with a history of hyperlipidemia, hypertension, and former smoking and a family history of premature coronary artery disease presented with acute substernal chest pain. She complained of progressive exertional dyspnea during the preceding weeks and of being under personal stress during this time. Her initial ECG showed ST-segment elevation of a maximum 0.2 mV and a reduced R-wave progression in the anteroseptal leads (V1-3). Her troponin T level was moderately elevated (0.3 ng/mL), with normal creatine kinase (CK) and CK-myocardial band (CK-MB) fraction. Cardiac catheterization was performed and showed angiographically normal epicardial coronary arteries. However, the left ventriculogram demonstrated midventricular dilatation and akinesis with a hypercontractile apex and base compatible with midventricular ballooning syndrome, a variant of Takotsubo cardiomyopathy (TTC) ( Figure 1A and 1B and Movie I in the online-only Data Supplement). Transthoracic echocardiographic monitoring during the next couple of days revealed no substantial changes in midventricular akinesis. Six days after the onset of symptoms, the patient underwent a simultaneous positron emission tomography (PET)/magnetic resonance (MR) examination of the heart performed on a whole-body integrated PET/MR scanner (Biograph mMR; Siemens Healthcare, Erlangen, Germany) using F-18 fluorodeoxyglucose (FDG) as a tracer. For PET scanning, the patient was prepared with a high-fat, low-carbohydrate diet the entire day before and a 12-hour fasting period before the examination. On cine-MR imaging, left ventricular midventricular dysfunction was unimproved ( Figure 2 and Movie II in the online-only Data Supplement) and delayed-contrast MR imaging did not depict any myocardial hyperenhancement ( Figure 3A and 3B). On PET scanning, suppressed FDG uptake within normal myocardium was noted, but a markedly increased glucose metabolism within the dysfunctional midventricular segments was indicated as well ( Figure 3C and 3D). Thus, combined PET/MR findings are compatible with stunned but viable myocardium that typically emerge during the acute phase of TTC (Movie III in the online-only Data Supplement). The patient was initiated on an

Functional and Histological Assessment of an Experimental Model of Takotsubo's Cardiomyopathy

“…In TC patients, integrated information from positron emission tomography (PET) and magnetic resonance imaging (MRI) scanning of the akinetic region, has revealed the transient shift from β‐fatty acid (β‐FA) oxidation to increased glucose metabolism resulting in free FA accumulation due to reduced uptake and utilization. Similar changes have been observed in the stunned myocardium, which strengthens the possibility that the viable stunned myocytes could be responsible for the wall motion abnormality …”

Acute stress-induced (takotsubo) cardiomyopathy

“…Small studies appear to suggest that microvascular perfusion remains functional in the malfunctioning myocardium at least to the degree where it does not jeopardise myocyte integrity both in the acute state and at 4 months follow-up. However, both reduced49 and increased50 glucose uptake has been reported in the ballooning segments, raising the possibility that the takotsubo myocyte may either have different degrees of insulin sensitivity or a swift ability to switch between substrates. If either or both should be the case, this may be exploited from a therapeutic standpoint.…”

Clinical applications of PET/MRI: current status and future perspectives

“…However, a recent study and several case reports have proved the technical feasibility and good image quality of cardiac PET/ MRI with FDG on an integrated scanner (41)(42)(43)(44).…”