Nuclear imaging in cardiac amyloidosis

Abstract

Amyloidosis is a disease characterized by depositions of amyloid in organs and tissues. It can be localized (in just one organ) or systemic. Cardiac amyloidosis is a debilitating disease and can lead to arrhythmias, deterioration of heart function and even sudden death. We reviewed PubMed/Medline, without time constraints, on the different nuclear imaging modalities that are used to visualize myocardial amyloid involvement. Several SPECT tracers have been used for this purpose. The results with these tracers in the evaluation of myocardial amyloidosis and their mechanisms of action are described. Most clinical evidence was found for the use of 123 I-MIBG. Myocardial defects in MIBG activity seem to correlate well with impaired cardiac sympathetic nerve endings due to amyloid deposits. 123 I-MIBG is an attractive option for objective evaluation of cardiac sympathetic level and may play an important role in the indirect measurement of the effect of amyloid myocardial infiltration. Other, less sensitive, options are 99m Tc-aprotinin for imaging amyloid deposits and perhaps 99m Tc-labelled phosphate derivatives, especially in the differential diagnosis of the aetiology of cardiac amyloidosis. PET tracers, despite the advantage of absolute quantification and higher resolution, are not yet well evaluated for the study of cardiac amyloidosis. Because of these advantages, there is still the need for further research in this field.

In vivo molecular imaging of peripheral amyloidosis using heparin-binding peptides

“…It provides images of amyloid load that can be used to compliment routine diagnosis by histochemical analysis of tissue biopsies, aid in prognostication, and document response to therapy (24,25). Although 123 I-SAP scintigraphy is the most common imaging technique for the detection of amyloid in the peripheral organs, other methods using 99m Tc-aprotinin and 99m Tc-3,3-diphosphon-1,2-propanodicarboxylic acid for imaging cardiac amyloid and ATTR, respectively, are also available (26)(27)(28)(29)(30). These methods are rarely used, however, because of the nonspecific nature of the interaction.…”

Nuclear Tracers for Transthyretin Cardiac Amyloidosis

“…14 Tc-DPD, widely used in Europe but unavailable in the United States, has had similarly excellent reported efficacy, showing ≈100% discrimination between amyloid type in small studies, whereas larger studies showed greater overlap. [15][16][17] That being said, Tc-DPD uptake is considered strongly suggestive of TTR.…”

Treatment of End Stage Heart Failure Related to Cardiac Amyloidosis

“…However its use in the heart is hampered by blood pool uptake [71] and it is available only in a few highly specialized centers. 99m-Tc-aprotinin may be fairly specific for cardiac amyloidosis but experience with this tecnique is limited [72].…”