The definitive diagnosis of
amyloidosis is made histologically with
Congo red stain. Noninvasive imaging techniques for
amyloidosis are beneficial for early and definite diagnosis of
amyloid deposition in the body. (99m)Tc-aprotinin has the benefit of detecting
amyloid deposits mainly in the heart, but it can also detect a wide range of lesions in other locations. The usefulness and limitations of (99m)Tc-Aprotinin scintigraphy for
amyloid imaging were re-evaluated based on results from 25 patients (15 men and 10 women; median age, 62.9 y; range, 34-83 y). In addition, other nuclear tracers for imaging
amyloidosis are discussed. Of the 25 patients with suspected
amyloidosis, 19 patients were proven to have
amyloid deposits by histopathological diagnosis. Major (99m)Tc-aprotinin positive sites were confirmed in the myocardium, thyroid, large joints, vertebrae, colon, and lungs. If (99m)Tc-Aprotinin images showed positive findings, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of existing
amyloid deposits were 94.7, 33.3, 81.8, and 66.7%, respectively. For analysis based on biopsy region, the sensitivity, specificity, PPV, and NPV of existing
amyloid deposition were 30.6, 82.6, 73.3, and 43.2%, respectively. (99m)Tc-Aprotinin has a high potential for diagnosis of
amyloid deposition in body; however, due to its physiological uptake, its potential is limited for detection of
amyloid deposits in the liver, kidney, and spleen.