biostudies-literatureAbrahamson EENIA NIH HHSNHLBI NIH HHS169-187https://www.ebi.ac.uk/biostudies/studies/S-EPMC10199962biostudies-literatureUnknown30(2)<h4>Background</h4>[¹⁸F]flutemetamol is a PET radioligand used to image brain amyloid, but its detection of myocardial amyloid is not well-characterized. This histological study characterized binding of fluorescently labeled flutemetamol (cyano-flutemetamol) to amyloid deposits in myocardium.<h4>Methods</h4>Myocardial tissue was obtained post-mortem from 29 subjects with cardiac amyloidosis including transthyretin wild-type (ATTRwt), hereditary/variant transthyretin (ATTRv) and immunoglobulin light-chain (AL) types, and from 10 cardiac amyloid-free controls. Most subjects had antemortem electrocardiography, echocardiography, SPECT and cardiac MRI. Cyano-flutemetamol labeling patterns and integrated density values were evaluated relative to fluorescent derivatives of Congo red (X-34) and Pittsburgh compound-B (cyano-PiB).<h4>Results</h4>Cyano-flutemetamol labeling was not detectable in control subjects. In subjects with cardiac amyloidosis, cyano-flutemetamol labeling matched X-34- and cyano-PiB-labeled, and transthyretin- or lambda light chain-immunoreactive, amyloid deposits and was prevented by formic acid pre-treatment of myocardial sections. Cyano-flutemetamol mean fluorescence intensity, when adjusted for X-34 signal, was higher in the ATTRwt than the AL group. Cyano-flutemetamol integrated density correlated strongly with echocardiography measures of ventricular septal thickness and posterior wall thickness, and with heart mass.<h4>Conclusion</h4>The high selectivity of cyano-flutemetamol binding to myocardial amyloid supports the diagnostic utility of [¹⁸F]flutemetamol PET imaging in patients with ATTR and AL types of cardiac amyloidosis.Amyloid : the international journal of experimental and clinical investigation : the official journal of the International Society of AmyloidosisThe flutemetamol analogue cyano-flutemetamol detects myocardial AL and ATTR amyloid deposits: a post-mortem histofluorescence analysis.PMC10199962R01 HL130563K24 HL157648P01 AG025204R01 HL150342P01 AG014449R01 AG052528K24 HL152008Abrahamson EEIkonomovic MDPadera RFDorbala SDavies JFarrar GVillemagne VLfalseThe flutemetamol analogue cyano-flutemetamol detects myocardial AL and ATTR amyloid deposits: a post-mortem histofluorescence analysis.<h4>Background</h4>[¹⁸F]flutemetamol is a PET radioligand used to image brain amyloid, but its detection of myocardial amyloid is not well-characterized. This histological study characterized binding of fluorescently labeled flutemetamol (cyano-flutemetamol) to amyloid deposits in myocardium.<h4>Methods</h4>Myocardial tissue was obtained post-mortem from 29 subjects with cardiac amyloidosis including transthyretin wild-type (ATTRwt), hereditary/variant transthyretin (ATTRv) and immunoglobulin light-chain (AL) types, and from 10 cardiac amyloid-free controls. Most subjects had antemortem electrocardiography, echocardiography, SPECT and cardiac MRI. Cyano-flutemetamol labeling patterns and integrated density values were evaluated relative to fluorescent derivatives of Congo red (X-34) and Pittsburgh compound-B (cyano-PiB).<h4>Results</h4>Cyano-flutemetamol labeling was not detectable in control subjects. In subjects with cardiac amyloidosis, cyano-flutemetamol labeling matched X-34- and cyano-PiB-labeled, and transthyretin- or lambda light chain-immunoreactive, amyloid deposits and was prevented by formic acid pre-treatment of myocardial sections. Cyano-flutemetamol mean fluorescence intensity, when adjusted for X-34 signal, was higher in the ATTRwt than the AL group. Cyano-flutemetamol integrated density correlated strongly with echocardiography measures of ventricular septal thickness and posterior wall thickness, and with heart mass.<h4>Conclusion</h4>The high selectivity of cyano-flutemetamol binding to myocardial amyloid supports the diagnostic utility of [¹⁸F]flutemetamol PET imaging in patients with ATTR and AL types of cardiac amyloidosis.2023-01-01T00:00:00Z2023 Jun2026-03-17T16:11:23.201Z2025-08-18T09:53:06.125ZS-EPMC101999623641150010.1080/13506129.2022.2141623