Nuclear Imaging of Amyloidosis

Abstract

Summary

Amyloidosis is a clinical condition caused by deposition of various protein fibrills in extracellular space. The presented symptoms depend on the type of deposits and the organ or organs involved. The correct diagnosis is often difficult, due to lack of nonivasive imaging techniques and insufficiency of morphological imaging procedures delievered by radiology. We presented a list of potential radiopharmaceuticals that can be used in detecting various types of amyloidoses. ¹²³I-SAP proved to have high sensitivity in imaging of AA and AL amyloidosis in visceral organs. ^99mTc-Aprotinin was found to be useful in detecting cardiac amyloidosis. A couple of classical radiotracers, such as ²⁰¹Tl, ¹²³I-mIBG, together with ¹¹¹In-antimyosin were also tested for accuracy in cardiac imaging, however the main problem was low specificity. Potential applicability was also found in case of some bone-seeking agents and other radiotracers, e.g. ⁶⁷Ga-citrate and ^99mTc-penta-DMSA. High sensitivity and specificity was achieved with β2-microglobulin labeled with ¹³¹I or ¹¹¹In. Among PET tracers, ¹¹C-PIB deserves more attention, because it may have an important role in diagnosing of AD in the near future. Further clinical studies are expected to take place, because noninvasive diagnosing and monitoring of amyloidosis is still a challenge.